Java的将任意格式转换为JSON数据格式的工具类

package org.sjw.utils;

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class JsonUtils {
    public static String stringToJson(String s) {
        if (s == null) {
            return nullToJson();
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            switch (ch) {
            case '"':
                sb.append("\\\"");
                break;
            case '\\':
                sb.append("\\\\");
                break;
            case '\b':
                sb.append("\\b");
                break;
            case '\f':
                sb.append("\\f");
                break;
            case '\n':
                sb.append("\\n");
                break;
            case '\r':
                sb.append("\\r");
                break;
            case '\t':
                sb.append("\\t");
                break;
            case '/':
                sb.append("\\/");
                break;
            default:
                if (ch >= '\u0000' && ch <= '\u001F') {
                    String ss = Integer.toHexString(ch);
                    sb.append("\\u");
                    for (int k = 0; k < 4 - ss.length(); k++) {
                        sb.append('0');
                    }
                    sb.append(ss.toUpperCase());
                } else {
                    sb.append(ch);
                }
            }
        }
        return sb.toString();
    }

    public static String nullToJson() {
        return "";
    }

    public static String objectToJson(Object obj) {
        StringBuilder json = new StringBuilder();
        if (obj == null) {
            json.append("\"\"");
        } else if (obj instanceof Number) {
            json.append(numberToJson((Number) obj));
        } else if (obj instanceof Boolean) {
            json.append(booleanToJson((Boolean) obj));
        } else if (obj instanceof String) {
            json.append("\"").append(stringToJson(obj.toString())).append("\"");
        } else if (obj instanceof Object[]) {
            json.append(arrayToJson((Object[]) obj));
        } else if (obj instanceof List) {
            json.append(listToJson((List<?>) obj));
        } else if (obj instanceof Map) {
            json.append(mapToJson((Map<?, ?>) obj));
        } else if (obj instanceof Set) {
            json.append(setToJson((Set<?>) obj));
        } else {
            json.append(beanToJson(obj));
        }
        return json.toString();
    }

    public static String numberToJson(Number number) {
        return number.toString();
    }

    public static String booleanToJson(Boolean bool) {
        return bool.toString();
    }

    /**
     * @param bean
     *            bean对象
     * @return String
     */
    public static String beanToJson(Object bean) {
        StringBuilder json = new StringBuilder();
        json.append("{");
        PropertyDescriptor[] props = null;
        try {
            props = Introspector.getBeanInfo(bean.getClass(), Object.class)
                    .getPropertyDescriptors();
        } catch (IntrospectionException e) {
        }
        if (props != null) {
            for (int i = 0; i < props.length; i++) {
                try {
                    String name = objectToJson(props[i].getName());
                    String value = http://www.mamicode.com/objectToJson(props[i].getReadMethod()>

将任意格式转换为JSON数据格式的工具类