import java.io.File;import java.io.FileInputStream;/** * 读取一个字符 */public class MyReadChar {    public static void main(String[] args) {        try {            File f = new File("D:\\labs\\test.txt");            FileInputStream fis = new FileInputStream(f);            System.out.println((char)fis.read());        } catch (Exception e) {        }    }}

import java.io.File;import java.io.FileInputStream;public class MyReadFile {    public static void main(String[] args) {        try {            File f = new File("D:\\labs\\test.txt");            FileInputStream fis = new FileInputStream(f);            int length = fis.available();            for (int i = 0; i <length; ++i) {                System.out.print((char)fis.read());            }        } catch (Exception e) {        }    }}

import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;public class MyCopyFile {    public static void main(String[] args) {        try {            File in = new File("D:\\labs\\test.txt");            File out = new File("D:\\labs\\another_test.txt");            FileInputStream fis = new FileInputStream(in);            FileOutputStream fos = new FileOutputStream(out);            int length = fis.available();            for (int i = 0; i < length; ++i) {                fos.write(fis.read());            }        } catch (Exception e) {        }    }}

import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;public class MyCopyBigFile {    public static void main(String[] args) {        try {            File in = new File("D:\\labs\\test.txt");            File out = new File("D:\\labs\\another_test.txt");            FileInputStream fis = new FileInputStream(in);            FileOutputStream fos = new FileOutputStream(out);            byte[] tmp = new byte[8192];            // 处理大部分内容            int length = fis.available()/8192;            for (int i = 0; i < length; ++i) {                fis.read(tmp);                fos.write(tmp);            }            int size = fis.read(tmp);            fos.write(tmp, 0, size);        } catch (Exception e) {        }    }}

import java.io.File;import java.io.FileOutputStream;public class MyKey {    public static void main(String[] args) {        try {            File f = new File("D:\\labs\\key.key");            FileOutputStream fos = new FileOutputStream(f);            for (int i = 0; i < 128; ++i) {                fos.write((int)(Math.random()*128));            }        } catch (Exception e) {        }    }}

import java.io.File;import java.io.FileInputStream;import java.io.FileOutputStream;public class MyEncryp {    public static void main(String[] args) {        try {            int key[] = new int[128];            File keyFile = new File("D:\\labs\\key.key");            FileInputStream keyFis = new FileInputStream(keyFile);            for (int i = 0; i < 128; ++i) {                key[i] = keyFis.read();            }            File in = new File("D:\\labs\\test.txt");            File out = new File("D:\\labs\\another_test.txt");            FileInputStream fis = new FileInputStream(in);            FileOutputStream fos = new FileOutputStream(out);            int length = fis.available();            for (int i = 0; i < length; ++i) {                fos.write(fis.read() + key[i%128]);            }        } catch (Exception e) {}    }}