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java常用工具类（java技术交流群57388149）

2024-07-09 22:11:52   223人阅读

package com.itjh.javaUtil;
 
import java.util.ArrayList;
import java.util.List;
 
/**
*
* String工具类. <br>
*
* @author 宋立君
* @date 2014年06月24日
*/
public class StringUtil {
 
    private static final int INDEX_NOT_FOUND = -1;
    private static final String EMPTY = "";
    /**
     * <p>
     * The maximum size to which the padding constant(s) can expand.
     * </p>
     */
    private static final int PAD_LIMIT = 8192;
 
    /**
     * 功能：将半角的符号转换成全角符号.(即英文字符转中文字符)
     *
     * @author 宋立君
     * @param str
     *            源字符串
     * @return String
     * @date 2014年06月24日
     */
    public static String changeToFull(String str) {
        String source = "1234567890!@#$%^&*()abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ-_=+\\|[];:‘\",<.>/?";
        String[] decode = { "１", "２", "３", "４", "５", "６", "７", "８", "９", "０",
                "！", "＠", "＃", "＄", "％", "︿", "＆", "＊", "（", "）", "ａ", "ｂ",
                "ｃ", "ｄ", "ｅ", "ｆ", "ｇ", "ｈ", "ｉ", "ｊ", "ｋ", "ｌ", "ｍ", "ｎ",
                "ｏ", "ｐ", "ｑ", "ｒ", "ｓ", "ｔ", "ｕ", "ｖ", "ｗ", "ｘ", "ｙ", "ｚ",
                "Ａ", "Ｂ", "Ｃ", "Ｄ", "Ｅ", "Ｆ", "Ｇ", "Ｈ", "Ｉ", "Ｊ", "Ｋ", "Ｌ",
                "Ｍ", "Ｎ", "Ｏ", "Ｐ", "Ｑ", "Ｒ", "Ｓ", "Ｔ", "Ｕ", "Ｖ", "Ｗ", "Ｘ",
                "Ｙ", "Ｚ", "－", "＿", "＝", "＋", "＼", "｜", "【", "】", "；", "：",
                "‘", "\"", "，", "〈", "。", "〉", "／", "？" };
        String result = "";
        for (int i = 0; i < str.length(); i++) {
            int pos = source.indexOf(str.charAt(i));
            if (pos != -1) {
                result += decode[pos];
            } else {
                result += str.charAt(i);
            }
        }
        return result;
    }
 
    /**
     * 功能：cs串中是否一个都不包含字符数组searchChars中的字符。
     *
     * @author 宋立君
     * @param cs
     *            字符串
     * @param searchChars
     *            字符数组
     * @return boolean 都不包含返回true，否则返回false。
     * @date 2014年06月24日
     */
    public static boolean containsNone(CharSequence cs, char... searchChars) {
        if (cs == null || searchChars == null) {
            return true;
        }
        int csLen = cs.length();
        int csLast = csLen - 1;
        int searchLen = searchChars.length;
        int searchLast = searchLen - 1;
        for (int i = 0; i < csLen; i++) {
            char ch = cs.charAt(i);
            for (int j = 0; j < searchLen; j++) {
                if (searchChars[j] == ch) {
                    if (Character.isHighSurrogate(ch)) {
                        if (j == searchLast) {
                            // missing low surrogate, fine, like
                            // String.indexOf(String)
                            return false;
                        }
                        if (i < csLast
                                && searchChars[j + 1] == cs.charAt(i + 1)) {
                            return false;
                        }
                    } else {
                        // ch is in the Basic Multilingual Plane
                        return false;
                    }
                }
            }
        }
        return true;
    }
 
    /**
     * <p>
     * 编码为Unicode，格式 ‘\u0020‘.
     * </p>
     *
     * @author 宋立君
     *
     *         <pre>
     *   CharUtils.unicodeEscaped(‘ ‘) = "\u0020"
     *   CharUtils.unicodeEscaped(‘A‘) = "\u0041"
     * </pre>
     *
     * @param ch
     *            源字符串
     * @return 转码后的字符串
     * @date 2014年06月24日
     */
    public static String unicodeEscaped(char ch) {
        if (ch < 0x10) {
            return "\\u000" + Integer.toHexString(ch);
        } else if (ch < 0x100) {
            return "\\u00" + Integer.toHexString(ch);
        } else if (ch < 0x1000) {
            return "\\u0" + Integer.toHexString(ch);
        }
        return "\\u" + Integer.toHexString(ch);
    }
 
    /**
     * <p>
     * 进行tostring操作，如果传入的是null，返回空字符串。
     * </p>
     *
     * <pre>
     * ObjectUtils.toString(null)         = ""
     * ObjectUtils.toString("")           = ""
     * ObjectUtils.toString("bat")        = "bat"
     * ObjectUtils.toString(Boolean.TRUE) = "true"
     * </pre>
     *
     * @param obj
     *            源
     * @return String
     */
    public static String toString(Object obj) {
        return obj == null ? "" : obj.toString();
    }
 
    /**
     * <p>
     * 进行tostring操作，如果传入的是null，返回指定的默认值。
     * </p>
     *
     * <pre>
     * ObjectUtils.toString(null, null)           = null
     * ObjectUtils.toString(null, "null")         = "null"
     * ObjectUtils.toString("", "null")           = ""
     * ObjectUtils.toString("bat", "null")        = "bat"
     * ObjectUtils.toString(Boolean.TRUE, "null") = "true"
     * </pre>
     *
     * @param obj
     *            源
     * @param nullStr
     *            如果obj为null时返回这个指定值
     * @return String
     */
    public static String toString(Object obj, String nullStr) {
        return obj == null ? nullStr : obj.toString();
    }
 
    /**
     * <p>
     * 只从源字符串中移除指定开头子字符串.
     * </p>
     *
     * <pre>
     * StringUtil.removeStart(null, *)      = null
     * StringUtil.removeStart("", *)        = ""
     * StringUtil.removeStart(*, null)      = *
     * StringUtil.removeStart("www.domain.com", "www.")   = "domain.com"
     * StringUtil.removeStart("domain.com", "www.")       = "domain.com"
     * StringUtil.removeStart("www.domain.com", "domain") = "www.domain.com"
     * StringUtil.removeStart("abc", "")    = "abc"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param remove
     *            将要被移除的子字符串
     * @return String
     */
    public static String removeStart(String str, String remove) {
        if (isEmpty(str) || isEmpty(remove)) {
            return str;
        }
        if (str.startsWith(remove)) {
            return str.substring(remove.length());
        }
        return str;
    }
 
    /**
     * <p>
     * 只从源字符串中移除指定结尾的子字符串.
     * </p>
     *
     * <pre>
     * StringUtil.removeEnd(null, *)      = null
     * StringUtil.removeEnd("", *)        = ""
     * StringUtil.removeEnd(*, null)      = *
     * StringUtil.removeEnd("www.domain.com", ".com.")  = "www.domain.com"
     * StringUtil.removeEnd("www.domain.com", ".com")   = "www.domain"
     * StringUtil.removeEnd("www.domain.com", "domain") = "www.domain.com"
     * StringUtil.removeEnd("abc", "")    = "abc"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param remove
     *            将要被移除的子字符串
     * @return String
     */
    public static String removeEnd(String str, String remove) {
        if (isEmpty(str) || isEmpty(remove)) {
            return str;
        }
        if (str.endsWith(remove)) {
            return str.substring(0, str.length() - remove.length());
        }
        return str;
    }
 
    /**
     * <p>
     * 将一个字符串重复N次
     * </p>
     *
     * <pre>
     * StringUtil.repeat(null, 2) = null
     * StringUtil.repeat("", 0)   = ""
     * StringUtil.repeat("", 2)   = ""
     * StringUtil.repeat("a", 3)  = "aaa"
     * StringUtil.repeat("ab", 2) = "abab"
     * StringUtil.repeat("a", -2) = ""
     * </pre>
     *
     * @param str
     *            源字符串
     * @param repeat
     *            重复的次数
     * @return String
     */
    public static String repeat(String str, int repeat) {
        // Performance tuned for 2.0 (JDK1.4)
 
        if (str == null) {
            return null;
        }
        if (repeat <= 0) {
            return EMPTY;
        }
        int inputLength = str.length();
        if (repeat == 1 || inputLength == 0) {
            return str;
        }
        if (inputLength == 1 && repeat <= PAD_LIMIT) {
            return repeat(str.charAt(0), repeat);
        }
 
        int outputLength = inputLength * repeat;
        switch (inputLength) {
        case 1:
            return repeat(str.charAt(0), repeat);
        case 2:
            char ch0 = str.charAt(0);
            char ch1 = str.charAt(1);
            char[] output2 = new char[outputLength];
            for (int i = repeat * 2 - 2; i >= 0; i--, i--) {
                output2[i] = ch0;
                output2[i + 1] = ch1;
            }
            return new String(output2);
        default:
            StringBuilder buf = new StringBuilder(outputLength);
            for (int i = 0; i < repeat; i++) {
                buf.append(str);
            }
            return buf.toString();
        }
    }
 
    /**
     * <p>
     * 将一个字符串重复N次，并且中间加上指定的分隔符
     * </p>
     *
     * <pre>
     * StringUtil.repeat(null, null, 2) = null
     * StringUtil.repeat(null, "x", 2)  = null
     * StringUtil.repeat("", null, 0)   = ""
     * StringUtil.repeat("", "", 2)     = ""
     * StringUtil.repeat("", "x", 3)    = "xxx"
     * StringUtil.repeat("?", ", ", 3)  = "?, ?, ?"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param separator
     *            分隔符
     * @param repeat
     *            重复次数
     * @return String
     */
    public static String repeat(String str, String separator, int repeat) {
        if (str == null || separator == null) {
            return repeat(str, repeat);
        } else {
            // given that repeat(String, int) is quite optimized, better to rely
            // on it than try and splice this into it
            String result = repeat(str + separator, repeat);
            return removeEnd(result, separator);
        }
    }
 
    /**
     * <p>
     * 将某个字符重复N次.
     * </p>
     *
     * @param ch
     *            某个字符
     * @param repeat
     *            重复次数
     * @return String
     */
    public static String repeat(char ch, int repeat) {
        char[] buf = new char[repeat];
        for (int i = repeat - 1; i >= 0; i--) {
            buf[i] = ch;
        }
        return new String(buf);
    }
 
    /**
     * <p>
     * 字符串长度达不到指定长度时，在字符串右边补指定的字符.
     * </p>
     *
     * <pre>
     * StringUtil.rightPad(null, *, *)     = null
     * StringUtil.rightPad("", 3, ‘z‘)     = "zzz"
     * StringUtil.rightPad("bat", 3, ‘z‘)  = "bat"
     * StringUtil.rightPad("bat", 5, ‘z‘)  = "batzz"
     * StringUtil.rightPad("bat", 1, ‘z‘)  = "bat"
     * StringUtil.rightPad("bat", -1, ‘z‘) = "bat"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            指定的长度
     * @param padChar
     *            进行补充的字符
     * @return String
     */
    public static String rightPad(String str, int size, char padChar) {
        if (str == null) {
            return null;
        }
        int pads = size - str.length();
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (pads > PAD_LIMIT) {
            return rightPad(str, size, String.valueOf(padChar));
        }
        return str.concat(repeat(padChar, pads));
    }
 
    /**
     * <p>
     * 扩大字符串长度，从左边补充指定字符
     * </p>
     *
     * <pre>
     * StringUtil.rightPad(null, *, *)      = null
     * StringUtil.rightPad("", 3, "z")      = "zzz"
     * StringUtil.rightPad("bat", 3, "yz")  = "bat"
     * StringUtil.rightPad("bat", 5, "yz")  = "batyz"
     * StringUtil.rightPad("bat", 8, "yz")  = "batyzyzy"
     * StringUtil.rightPad("bat", 1, "yz")  = "bat"
     * StringUtil.rightPad("bat", -1, "yz") = "bat"
     * StringUtil.rightPad("bat", 5, null)  = "bat  "
     * StringUtil.rightPad("bat", 5, "")    = "bat  "
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            扩大后的长度
     * @param padStr
     *            在右边补充的字符串
     * @return String
     */
    public static String rightPad(String str, int size, String padStr) {
        if (str == null) {
            return null;
        }
        if (isEmpty(padStr)) {
            padStr = " ";
        }
        int padLen = padStr.length();
        int strLen = str.length();
        int pads = size - strLen;
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (padLen == 1 && pads <= PAD_LIMIT) {
            return rightPad(str, size, padStr.charAt(0));
        }
 
        if (pads == padLen) {
            return str.concat(padStr);
        } else if (pads < padLen) {
            return str.concat(padStr.substring(0, pads));
        } else {
            char[] padding = new char[pads];
            char[] padChars = padStr.toCharArray();
            for (int i = 0; i < pads; i++) {
                padding[i] = padChars[i % padLen];
            }
            return str.concat(new String(padding));
        }
    }
 
    /**
     * <p>
     * 扩大字符串长度，从左边补充空格
     * </p>
     *
     * <pre>
     * StringUtil.leftPad(null, *)   = null
     * StringUtil.leftPad("", 3)     = "   "
     * StringUtil.leftPad("bat", 3)  = "bat"
     * StringUtil.leftPad("bat", 5)  = "  bat"
     * StringUtil.leftPad("bat", 1)  = "bat"
     * StringUtil.leftPad("bat", -1) = "bat"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            扩大后的长度
     * @return String
     */
    public static String leftPad(String str, int size) {
        return leftPad(str, size, ‘ ‘);
    }
 
    /**
     * <p>
     * 扩大字符串长度，从左边补充指定的字符
     * </p>
     *
     * <pre>
     * StringUtil.leftPad(null, *, *)     = null
     * StringUtil.leftPad("", 3, ‘z‘)     = "zzz"
     * StringUtil.leftPad("bat", 3, ‘z‘)  = "bat"
     * StringUtil.leftPad("bat", 5, ‘z‘)  = "zzbat"
     * StringUtil.leftPad("bat", 1, ‘z‘)  = "bat"
     * StringUtil.leftPad("bat", -1, ‘z‘) = "bat"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            扩大后的长度
     * @param padStr
     *            补充的字符
     * @return String
     */
    public static String leftPad(String str, int size, char padChar) {
        if (str == null) {
            return null;
        }
        int pads = size - str.length();
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (pads > PAD_LIMIT) {
            return leftPad(str, size, String.valueOf(padChar));
        }
        return repeat(padChar, pads).concat(str);
    }
 
    /**
     * <p>
     * 扩大字符串长度，从左边补充指定的字符
     * </p>
     *
     * <pre>
     * StringUtil.leftPad(null, *, *)      = null
     * StringUtil.leftPad("", 3, "z")      = "zzz"
     * StringUtil.leftPad("bat", 3, "yz")  = "bat"
     * StringUtil.leftPad("bat", 5, "yz")  = "yzbat"
     * StringUtil.leftPad("bat", 8, "yz")  = "yzyzybat"
     * StringUtil.leftPad("bat", 1, "yz")  = "bat"
     * StringUtil.leftPad("bat", -1, "yz") = "bat"
     * StringUtil.leftPad("bat", 5, null)  = "  bat"
     * StringUtil.leftPad("bat", 5, "")    = "  bat"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            扩大后的长度
     * @param padStr
     *            补充的字符串
     * @return String
     */
    public static String leftPad(String str, int size, String padStr) {
        if (str == null) {
            return null;
        }
        if (isEmpty(padStr)) {
            padStr = " ";
        }
        int padLen = padStr.length();
        int strLen = str.length();
        int pads = size - strLen;
        if (pads <= 0) {
            return str; // returns original String when possible
        }
        if (padLen == 1 && pads <= PAD_LIMIT) {
            return leftPad(str, size, padStr.charAt(0));
        }
 
        if (pads == padLen) {
            return padStr.concat(str);
        } else if (pads < padLen) {
            return padStr.substring(0, pads).concat(str);
        } else {
            char[] padding = new char[pads];
            char[] padChars = padStr.toCharArray();
            for (int i = 0; i < pads; i++) {
                padding[i] = padChars[i % padLen];
            }
            return new String(padding).concat(str);
        }
    }
 
    /**
     * <p>
     * 扩大字符串长度并将现在的字符串居中，被扩大部分用空格填充。
     * <p>
     *
     * <pre>
     * StringUtil.center(null, *)   = null
     * StringUtil.center("", 4)     = "    "
     * StringUtil.center("ab", -1)  = "ab"
     * StringUtil.center("ab", 4)   = " ab "
     * StringUtil.center("abcd", 2) = "abcd"
     * StringUtil.center("a", 4)    = " a  "
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            扩大后的长度
     * @return String
     */
    public static String center(String str, int size) {
        return center(str, size, ‘ ‘);
    }
 
    /**
     * <p>
     * 将字符串长度修改为指定长度，并进行居中显示。
     * </p>
     *
     * <pre>
     * StringUtil.center(null, *, *)     = null
     * StringUtil.center("", 4, ‘ ‘)     = "    "
     * StringUtil.center("ab", -1, ‘ ‘)  = "ab"
     * StringUtil.center("ab", 4, ‘ ‘)   = " ab"
     * StringUtil.center("abcd", 2, ‘ ‘) = "abcd"
     * StringUtil.center("a", 4, ‘ ‘)    = " a  "
     * StringUtil.center("a", 4, ‘y‘)    = "yayy"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            指定的长度
     * @param padStr
     *            长度不够时补充的字符串
     * @return String
     * @throws IllegalArgumentException
     *             如果被补充字符串为 null或者 empty
     */
    public static String center(String str, int size, char padChar) {
        if (str == null || size <= 0) {
            return str;
        }
        int strLen = str.length();
        int pads = size - strLen;
        if (pads <= 0) {
            return str;
        }
        str = leftPad(str, strLen + pads / 2, padChar);
        str = rightPad(str, size, padChar);
        return str;
    }
 
    /**
     * <p>
     * 将字符串长度修改为指定长度，并进行居中显示。
     * </p>
     *
     * <pre>
     * StringUtil.center(null, *, *)     = null
     * StringUtil.center("", 4, " ")     = "    "
     * StringUtil.center("ab", -1, " ")  = "ab"
     * StringUtil.center("ab", 4, " ")   = " ab"
     * StringUtil.center("abcd", 2, " ") = "abcd"
     * StringUtil.center("a", 4, " ")    = " a  "
     * StringUtil.center("a", 4, "yz")   = "yayz"
     * StringUtil.center("abc", 7, null) = "  abc  "
     * StringUtil.center("abc", 7, "")   = "  abc  "
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            指定的长度
     * @param padStr
     *            长度不够时补充的字符串
     * @return String
     * @throws IllegalArgumentException
     *             如果被补充字符串为 null或者 empty
     */
    public static String center(String str, int size, String padStr) {
        if (str == null || size <= 0) {
            return str;
        }
        if (isEmpty(padStr)) {
            padStr = " ";
        }
        int strLen = str.length();
        int pads = size - strLen;
        if (pads <= 0) {
            return str;
        }
        str = leftPad(str, strLen + pads / 2, padStr);
        str = rightPad(str, size, padStr);
        return str;
    }
 
    /**
     * <p>
     * 检查字符串是否全部为小写.
     * </p>
     *
     * <pre>
     * StringUtil.isAllLowerCase(null)   = false
     * StringUtil.isAllLowerCase("")     = false
     * StringUtil.isAllLowerCase("  ")   = false
     * StringUtil.isAllLowerCase("abc")  = true
     * StringUtil.isAllLowerCase("abC") = false
     * </pre>
     *
     * @param cs
     *            源字符串
     * @return String
     */
    public static boolean isAllLowerCase(String cs) {
        if (cs == null || isEmpty(cs)) {
            return false;
        }
        int sz = cs.length();
        for (int i = 0; i < sz; i++) {
            if (Character.isLowerCase(cs.charAt(i)) == false) {
                return false;
            }
        }
        return true;
    }
 
    /**
     * <p>
     * 检查是否都是大写.
     * </p>
     *
     * <pre>
     * StringUtil.isAllUpperCase(null)   = false
     * StringUtil.isAllUpperCase("")     = false
     * StringUtil.isAllUpperCase("  ")   = false
     * StringUtil.isAllUpperCase("ABC")  = true
     * StringUtil.isAllUpperCase("aBC") = false
     * </pre>
     *
     * @param cs
     *            源字符串
     * @return String
     */
    public static boolean isAllUpperCase(String cs) {
        if (cs == null || StringUtil.isEmpty(cs)) {
            return false;
        }
        int sz = cs.length();
        for (int i = 0; i < sz; i++) {
            if (Character.isUpperCase(cs.charAt(i)) == false) {
                return false;
            }
        }
        return true;
    }
 
    /**
     * <p>
     * 反转字符串.
     * </p>
     *
     * <pre>
     * StringUtil.reverse(null)  = null
     * StringUtil.reverse("")    = ""
     * StringUtil.reverse("bat") = "tab"
     * </pre>
     *
     * @param str
     *            源字符串
     * @return String
     */
    public static String reverse(String str) {
        if (str == null) {
            return null;
        }
        return new StringBuilder(str).reverse().toString();
    }
 
    /**
     * <p>
     * 字符串达不到一定长度时在右边补空白.
     * </p>
     *
     * <pre>
     * StringUtil.rightPad(null, *)   = null
     * StringUtil.rightPad("", 3)     = "   "
     * StringUtil.rightPad("bat", 3)  = "bat"
     * StringUtil.rightPad("bat", 5)  = "bat  "
     * StringUtil.rightPad("bat", 1)  = "bat"
     * StringUtil.rightPad("bat", -1) = "bat"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param size
     *            指定的长度
     * @return String
     */
    public static String rightPad(String str, int size) {
        return rightPad(str, size, ‘ ‘);
    }
 
    /**
     * 从右边截取字符串.</p>
     *
     * <pre>
     * StringUtil.right(null, *)    = null
     * StringUtil.right(*, -ve)     = ""
     * StringUtil.right("", *)      = ""
     * StringUtil.right("abc", 0)   = ""
     * StringUtil.right("abc", 2)   = "bc"
     * StringUtil.right("abc", 4)   = "abc"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param len
     *            长度
     * @return String
     */
    public static String right(String str, int len) {
        if (str == null) {
            return null;
        }
        if (len < 0) {
            return EMPTY;
        }
        if (str.length() <= len) {
            return str;
        }
        return str.substring(str.length() - len);
    }
 
    /**
     * <p>
     * 截取一个字符串的前几个.
     * </p>
     *
     * <pre>
     * StringUtil.left(null, *)    = null
     * StringUtil.left(*, -ve)     = ""
     * StringUtil.left("", *)      = ""
     * StringUtil.left("abc", 0)   = ""
     * StringUtil.left("abc", 2)   = "ab"
     * StringUtil.left("abc", 4)   = "abc"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param len
     *            截取的长度
     * @return the String
     */
    public static String left(String str, int len) {
        if (str == null) {
            return null;
        }
        if (len < 0) {
            return EMPTY;
        }
        if (str.length() <= len) {
            return str;
        }
        return str.substring(0, len);
    }
 
    /**
     * <p>
     * 得到tag字符串中间的子字符串，只返回第一个匹配项。
     * </p>
     *
     * <pre>
     * StringUtil.substringBetween(null, *)            = null
     * StringUtil.substringBetween("", "")             = ""
     * StringUtil.substringBetween("", "tag")          = null
     * StringUtil.substringBetween("tagabctag", null)  = null
     * StringUtil.substringBetween("tagabctag", "")    = ""
     * StringUtil.substringBetween("tagabctag", "tag") = "abc"
     * </pre>
     *
     * @param str
     *            源字符串。
     * @param tag
     *            标识字符串。
     * @return String 子字符串, 如果没有符合要求的，返回{@code null}。
     */
    public static String substringBetween(String str, String tag) {
        return substringBetween(str, tag, tag);
    }
 
    /**
     * <p>
     * 得到两个字符串中间的子字符串，只返回第一个匹配项。
     * </p>
     *
     * <pre>
     * StringUtil.substringBetween("wx[b]yz", "[", "]") = "b"
     * StringUtil.substringBetween(null, *, *)          = null
     * StringUtil.substringBetween(*, null, *)          = null
     * StringUtil.substringBetween(*, *, null)          = null
     * StringUtil.substringBetween("", "", "")          = ""
     * StringUtil.substringBetween("", "", "]")         = null
     * StringUtil.substringBetween("", "[", "]")        = null
     * StringUtil.substringBetween("yabcz", "", "")     = ""
     * StringUtil.substringBetween("yabcz", "y", "z")   = "abc"
     * StringUtil.substringBetween("yabczyabcz", "y", "z")   = "abc"
     * </pre>
     *
     * @param str
     *            源字符串
     * @param open
     *            起字符串。
     * @param close
     *            末字符串。
     * @return String 子字符串, 如果没有符合要求的，返回{@code null}。
     */
    public static String substringBetween(String str, String open, String close) {
        if (str == null || open == null || close == null) {
            return null;
        }
        int start = str.indexOf(open);
        if (start != INDEX_NOT_FOUND) {
            int end = str.indexOf(close, start + open.length());
            if (end != INDEX_NOT_FOUND) {
                return str.substring(start + open.length(), end);
            }
        }
        return null;
    }
 
    /**
     * <p>
     * 得到两个字符串中间的子字符串，所有匹配项组合为数组并返回。
     * </p>
     *
     * <pre>
     * StringUtil.substringsBetween("[a][b][c]", "[", "]") = ["a","b","c"]
     * StringUtil.substringsBetween(null, *, *)            = null
     * StringUtil.substringsBetween(*, null, *)            = null
     * StringUtil.substringsBetween(*, *, null)            = null
     * StringUtil.substringsBetween("", "[", "]")          = []
     * </pre>
     *
     * @param str
     *            源字符串
     * @param open
     *            起字符串。
     * @param close
     *            末字符串。
     * @return String 子字符串数组, 如果没有符合要求的，返回{@code null}。
     */
    public static String[] substringsBetween(String str, String open,
            String close) {
        if (str == null || isEmpty(open) || isEmpty(close)) {
            return null;
        }
        int strLen = str.length();
        if (strLen == 0) {
            return new String[0];
        }
        int closeLen = close.length();
        int openLen = open.length();
        List<String> list = new ArrayList<String>();
        int pos = 0;
        while (pos < strLen - closeLen) {
            int start = str.indexOf(open, pos);
            if (start < 0) {
                break;
            }
            start += openLen;
            int end = str.indexOf(close, start);
            if (end < 0) {
                break;
            }
            list.add(str.substring(start, end));
            pos = end + closeLen;
        }
        if (list.isEmpty()) {
            return null;
        }
        return list.toArray(new String[list.size()]);
    }
 
    /**
     * 功能：切换字符串中的所有字母大小写。<br/>
     *
     * <pre>
     * StringUtil.swapCase(null)                 = null
     * StringUtil.swapCase("")                   = ""
     * StringUtil.swapCase("The dog has a BONE") = "tHE DOG HAS A bone"
     * </pre>
     *
     *
     * @param str
     *            源字符串
     * @return String
     */
    public static String swapCase(String str) {
        if (StringUtil.isEmpty(str)) {
            return str;
        }
        char[] buffer = str.toCharArray();
 
        boolean whitespace = true;
 
        for (int i = 0; i < buffer.length; i++) {
            char ch = buffer[i];
            if (Character.isUpperCase(ch)) {
                buffer[i] = Character.toLowerCase(ch);
                whitespace = false;
            } else if (Character.isTitleCase(ch)) {
                buffer[i] = Character.toLowerCase(ch);
                whitespace = false;
            } else if (Character.isLowerCase(ch)) {
                if (whitespace) {
                    buffer[i] = Character.toTitleCase(ch);
                    whitespace = false;
                } else {
                    buffer[i] = Character.toUpperCase(ch);
                }
            } else {
                whitespace = Character.isWhitespace(ch);
            }
        }
        return new String(buffer);
    }
 
    /**
     * 功能：截取出最后一个标志位之后的字符串.<br/>
     * 如果sourceStr为empty或者expr为null，直接返回源字符串。<br/>
     * 如果expr长度为0，直接返回sourceStr。<br/>
     * 如果expr在sourceStr中不存在，直接返回sourceStr。<br/>
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param sourceStr
     *            被截取的字符串
     * @param expr
     *            分隔符
     * @return String
     */
    public static String substringAfterLast(String sourceStr, String expr) {
        if (isEmpty(sourceStr) || expr == null) {
            return sourceStr;
        }
        if (expr.length() == 0) {
            return sourceStr;
        }
 
        int pos = sourceStr.lastIndexOf(expr);
        if (pos == -1) {
            return sourceStr;
        }
        return sourceStr.substring(pos + expr.length());
    }
 
    /**
     * 功能：截取出最后一个标志位之前的字符串.<br/>
     * 如果sourceStr为empty或者expr为null，直接返回源字符串。<br/>
     * 如果expr长度为0，直接返回sourceStr。<br/>
     * 如果expr在sourceStr中不存在，直接返回sourceStr。<br/>
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param sourceStr
     *            被截取的字符串
     * @param expr
     *            分隔符
     * @return String
     */
    public static String substringBeforeLast(String sourceStr, String expr) {
        if (isEmpty(sourceStr) || expr == null) {
            return sourceStr;
        }
        if (expr.length() == 0) {
            return sourceStr;
        }
        int pos = sourceStr.lastIndexOf(expr);
        if (pos == -1) {
            return sourceStr;
        }
        return sourceStr.substring(0, pos);
    }
 
    /**
     * 功能：截取出第一个标志位之后的字符串.<br/>
     * 如果sourceStr为empty或者expr为null，直接返回源字符串。<br/>
     * 如果expr长度为0，直接返回sourceStr。<br/>
     * 如果expr在sourceStr中不存在，直接返回sourceStr。<br/>
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param sourceStr
     *            被截取的字符串
     * @param expr
     *            分隔符
     * @return String
     */
    public static String substringAfter(String sourceStr, String expr) {
        if (isEmpty(sourceStr) || expr == null) {
            return sourceStr;
        }
        if (expr.length() == 0) {
            return sourceStr;
        }
 
        int pos = sourceStr.indexOf(expr);
        if (pos == -1) {
            return sourceStr;
        }
        return sourceStr.substring(pos + expr.length());
    }
 
    /**
     * 功能：截取出第一个标志位之前的字符串.<br/>
     * 如果sourceStr为empty或者expr为null，直接返回源字符串。<br/>
     * 如果expr长度为0，直接返回sourceStr。<br/>
     * 如果expr在sourceStr中不存在，直接返回sourceStr。<br/>
     * 如果expr在sourceStr中存在不止一个，以第一个位置为准。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param sourceStr
     *            被截取的字符串
     * @param expr
     *            分隔符
     * @return String
     */
    public static String substringBefore(String sourceStr, String expr) {
        if (isEmpty(sourceStr) || expr == null) {
            return sourceStr;
        }
        if (expr.length() == 0) {
            return sourceStr;
        }
        int pos = sourceStr.indexOf(expr);
        if (pos == -1) {
            return sourceStr;
        }
        return sourceStr.substring(0, pos);
    }
 
    /**
     * 功能：检查这个字符串是不是空字符串。<br/>
     * 如果这个字符串为null或者trim后为空字符串则返回true，否则返回false。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param chkStr
     *            被检查的字符串
     * @return boolean
     */
    public static boolean isEmpty(String chkStr) {
        if (chkStr == null) {
            return true;
        } else {
            return "".equals(chkStr.trim()) ? true : false;
        }
    }
 
    /**
     * 如果字符串没有超过最长显示长度返回原字符串，否则从开头截取指定长度并加...返回。
     *
     * @param str
     *            原字符串
     * @param length
     *            字符串最长显示的长度
     * @return 转换后的字符串
     */
    public static String trimString(String str, int length) {
        if (str == null) {
            return "";
        } else if (str.length() > length) {
            return str.substring(0, length - 3) + "...";
        } else {
            return str;
        }
    }
 
}

二、MD5

 
 
 
 
 
Java
 
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package com.itjh.javaUtil;
 
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
 
/**
*
* String工具类. <br>
*
* @author 宋立君
* @date 2014年06月24日
*/
public class MD5Util {
 
    protected static char hexDigits[] = { ‘0‘, ‘1‘, ‘2‘, ‘3‘, ‘4‘, ‘5‘, ‘6‘,
            ‘7‘, ‘8‘, ‘9‘, ‘a‘, ‘b‘, ‘c‘, ‘d‘, ‘e‘, ‘f‘ };
 
    protected static MessageDigest messagedigest = null;
 
    static {
        try {
            messagedigest = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException nsaex) {
            System.err.println(MD5Util.class.getName()
                    + "初始化失败，MessageDigest不支持MD5Util。");
            nsaex.printStackTrace();
        }
    }
 
    /**
     * 功能：加盐版的MD5.返回格式为MD5(密码+{盐值})
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param password
     *            密码
     * @param salt
     *            盐值
     * @return String
     */
    public static String getMD5StringWithSalt(String password, String salt) {
        if (password == null) {
            throw new IllegalArgumentException("password不能为null");
        }
        if (StringUtil.isEmpty(salt)) {
            throw new IllegalArgumentException("salt不能为空");
        }
        if ((salt.toString().lastIndexOf("{") != -1)
                || (salt.toString().lastIndexOf("}") != -1)) {
            throw new IllegalArgumentException("salt中不能包含 { 或者 }");
        }
        return getMD5String(password + "{" + salt.toString() + "}");
    }
 
    /**
     * 功能：得到文件的md5值。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param file
     *            文件。
     * @return String
     * @throws IOException
     *             读取文件IO异常时。
     */
    public static String getFileMD5String(File file) throws IOException {
        FileInputStream in = new FileInputStream(file);
        FileChannel ch = in.getChannel();
        MappedByteBuffer byteBuffer = ch.map(FileChannel.MapMode.READ_ONLY, 0,
                file.length());
        messagedigest.update(byteBuffer);
        return bufferToHex(messagedigest.digest());
    }
 
    /**
     * 功能：得到一个字符串的MD5值。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param str
     *            字符串
     * @return String
     */
    public static String getMD5String(String str) {
        return getMD5String(str.getBytes());
    }
 
    private static String getMD5String(byte[] bytes) {
        messagedigest.update(bytes);
        return bufferToHex(messagedigest.digest());
    }
 
    private static String bufferToHex(byte bytes[]) {
        return bufferToHex(bytes, 0, bytes.length);
    }
 
    private static String bufferToHex(byte bytes[], int m, int n) {
        StringBuffer stringbuffer = new StringBuffer(2 * n);
        int k = m + n;
        for (int l = m; l < k; l++) {
            appendHexPair(bytes[l], stringbuffer);
        }
        return stringbuffer.toString();
    }
 
    private static void appendHexPair(byte bt, StringBuffer stringbuffer) {
        char c0 = hexDigits[(bt & 0xf0) >> 4];
        char c1 = hexDigits[bt & 0xf];
        stringbuffer.append(c0);
        stringbuffer.append(c1);
    }
}

三、File工具类

 
 
 
 
 
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package com.itjh.javaUtil;
 
import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
 
/**
* 文件相关操作辅助类。
*
* @author 宋立君
* @date 2014年06月24日
*/
public class FileUtil {
    private static final String FOLDER_SEPARATOR = "/";
    private static final char EXTENSION_SEPARATOR = ‘.‘;
 
    /**
     * 功能：复制文件或者文件夹。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param inputFile
     *            源文件
     * @param outputFile
     *            目的文件
     * @param isOverWrite
     *            是否覆盖(只针对文件)
     * @throws IOException
     */
    public static void copy(File inputFile, File outputFile, boolean isOverWrite)
            throws IOException {
        if (!inputFile.exists()) {
            throw new RuntimeException(inputFile.getPath() + "源目录不存在!");
        }
        copyPri(inputFile, outputFile, isOverWrite);
    }
 
    /**
     * 功能：为copy 做递归使用。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param inputFile
     * @param outputFile
     * @param isOverWrite
     * @throws IOException
     */
    private static void copyPri(File inputFile, File outputFile,
            boolean isOverWrite) throws IOException {
        // 是个文件。
        if (inputFile.isFile()) {
            copySimpleFile(inputFile, outputFile, isOverWrite);
        } else {
            // 文件夹
            if (!outputFile.exists()) {
                outputFile.mkdir();
            }
            // 循环子文件夹
            for (File child : inputFile.listFiles()) {
                copy(child,
                        new File(outputFile.getPath() + "/" + child.getName()),
                        isOverWrite);
            }
        }
    }
 
    /**
     * 功能：copy单个文件
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param inputFile
     *            源文件
     * @param outputFile
     *            目标文件
     * @param isOverWrite
     *            是否允许覆盖
     * @throws IOException
     */
    private static void copySimpleFile(File inputFile, File outputFile,
            boolean isOverWrite) throws IOException {
        // 目标文件已经存在
        if (outputFile.exists()) {
            if (isOverWrite) {
                if (!outputFile.delete()) {
                    throw new RuntimeException(outputFile.getPath() + "无法覆盖！");
                }
            } else {
                // 不允许覆盖
                return;
            }
        }
        InputStream in = new FileInputStream(inputFile);
        OutputStream out = new FileOutputStream(outputFile);
        byte[] buffer = new byte[1024];
        int read = 0;
        while ((read = in.read(buffer)) != -1) {
            out.write(buffer, 0, read);
        }
        in.close();
        out.close();
    }
 
    /**
     * 功能：删除文件
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param file
     *            文件
     */
    public static void delete(File file) {
        deleteFile(file);
    }
 
    /**
     * 功能：删除文件，内部递归使用
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param file
     *            文件
     * @return boolean true 删除成功，false 删除失败。
     */
    private static void deleteFile(File file) {
        if (file == null || !file.exists()) {
            return;
        }
        // 单文件
        if (!file.isDirectory()) {
            boolean delFlag = file.delete();
            if (!delFlag) {
                throw new RuntimeException(file.getPath() + "删除失败！");
            } else {
                return;
            }
        }
        // 删除子目录
        for (File child : file.listFiles()) {
            deleteFile(child);
        }
        // 删除自己
        file.delete();
    }
 
    /**
     * 从文件路径中抽取文件的扩展名, 例如. "mypath/myfile.txt" -> "txt". * @author 宋立君
     *
     * @date 2014年06月24日
     * @param 文件路径
     * @return 如果path为null，直接返回null。
     */
    public static String getFilenameExtension(String path) {
        if (path == null) {
            return null;
        }
        int extIndex = path.lastIndexOf(EXTENSION_SEPARATOR);
        if (extIndex == -1) {
            return null;
        }
        int folderIndex = path.lastIndexOf(FOLDER_SEPARATOR);
        if (folderIndex > extIndex) {
            return null;
        }
        return path.substring(extIndex + 1);
    }
 
    /**
     * 从文件路径中抽取文件名, 例如： "mypath/myfile.txt" -> "myfile.txt"。 * @author 宋立君
     *
     * @date 2014年06月24日
     * @param path
     *            文件路径。
     * @return 抽取出来的文件名, 如果path为null，直接返回null。
     */
    public static String getFilename(String path) {
        if (path == null) {
            return null;
        }
        int separatorIndex = path.lastIndexOf(FOLDER_SEPARATOR);
        return (separatorIndex != -1 ? path.substring(separatorIndex + 1)
                : path);
    }
 
    /**
     * 功能：保存文件。
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param content
     *            字节
     * @param file
     *            保存到的文件
     * @throws IOException
     */
    public static void save(byte[] content, File file) throws IOException {
        if (file == null) {
            throw new RuntimeException("保存文件不能为空");
        }
        if (content == null) {
            throw new RuntimeException("文件流不能为空");
        }
        InputStream is = new ByteArrayInputStream(content);
        save(is, file);
    }
 
    /**
     * 功能：保存文件
     *
     * @author 宋立君
     * @date 2014年06月24日
     * @param streamIn
     *            文件流
     * @param file
     *            保存到的文件
     * @throws IOException
     */
    public static void save(InputStream streamIn, File file) throws IOException {
        if (file == null) {
            throw new RuntimeException("保存文件不能为空");
        }
        if (streamIn == null) {
            throw new RuntimeException("文件流不能为空");
        }
        // 输出流
        OutputStream streamOut = null;
        // 文件夹不存在就创建。
        if (!file.getParentFile().exists()) {
            file.getParentFile().mkdirs();
        }
        streamOut = new FileOutputStream(file);
        int bytesRead = 0;
        byte[] buffer = new byte[8192];
        while ((bytesRead = streamIn.read(buffer, 0, 8192)) != -1) {
            streamOut.write(buffer, 0, bytesRead);
        }
        streamOut.close();
        streamIn.close();
    }
}

转载于IT江湖


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