Java字符转码之UTF-8互转GBK具体实现

package string;
import java.nio.charset.Charset;
public class UTF82GBK {
    public static void main(String[] args) throws Exception {
        //系统的默认编码是GBK
        System.out.println("Default Charset=" + Charset.defaultCharset());
        String t = "hfjkds中国中国中国中国中国中国中国中国中国中国中国中国中国中国中国中国中国中国中国中国hfsdkj<img src=‘sasa‘ /> fjldsajflkdsjaflkdsjalf <img src=‘sada‘ ait=‘‘/>sfdsfadas";  
        //思路：先转为Unicode，然后转为GBK
        String utf8 = new String(t.getBytes( "UTF-8"));
        //等同于:
//        String utf8 = new String(t.getBytes( "UTF-8"),Charset.defaultCharset());
        System.out.println(utf8);  
        String unicode = new String(utf8.getBytes(),"UTF-8");   
        //等同于:
//        String unicode = new String(utf8.getBytes(Charset.defaultCharset()),"UTF-8");   
        System.out.println(unicode);  
        String gbk = new String(unicode.getBytes("GBK"));  
        //等同于:
//        String gbk = new String(unicode.getBytes("GBK"),Charset.defaultCharset());  
        System.out.println(gbk);  
    }
}

package com.mkyong;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class UTF8ToGBK {
    public static void main(String[] args) throws Exception {
        File fileDir = new File("/home/user/Desktop/Unsaved Document 1");
        BufferedReader in = new BufferedReader(new InputStreamReader(
                new FileInputStream(fileDir), "UTF-8"));
        String str;
        while ((str = in.readLine()) != null) {
            System.out.println(str);// java内部只有unicode编码 所以str是unicode编码
            String str2 = new String(str.getBytes("GBK"), "GBK");// str.getBytes("GBK")是gbk编码，但是str2是unicode编码
            System.out.println(str2);
        }
        in.close();
    }
}

String fullStr = new String(str.getBytes("UTF-8"), "UTF-8");//正常
String fullStr2 = new String(str.getBytes("UTF-8"), "GBK");//不正常，java内置的编码->utf8  被当成GBK编码转换成java内置的编码

public String(byte[] bytes,
      Charset charset)

String str3 = new String(str.getBytes("GBK"),"ISO-8859-1");
System.out.println(new String(str3.getBytes("ISO-8859-1"),"GBK"));

FileInputStream fileInputStream = new FileInputStream("gbk.txt");
    InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "GBK");
    FileOutputStream fileOutputStream = new FileOutputStream("utf-8.txt");
    OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fileOutputStream, "UTF-8");
    int length = 0;
    char[] buffer = new char[1024];
    while ((length = inputStreamReader.read(buffer)) != -1) {
        outputStreamWriter.write(buffer, 0, length);
    }
    outputStreamWriter.close();
    fileOutputStream.close();
    inputStreamReader.close();
    fileInputStream.close();

String strGBK = "这是一段GBK编码的字符串";
    byte[] bytes = strGBK.getBytes("GBK");
    String strUTF = new String(bytes,"UTF-8");
    System.out.println(strUTF);

String strGBK = "这是一段GBK编码的字符串";
    Charset gbkCharset = Charset.forName("GBK");
    Charset utf8Charset = Charset.forName("UTF-8");
    ByteBuffer byteBuffer = gbkCharset .encode(strGBK);
    CharBuffer charBuffer = utf8Charset .decode(byteBuffer);
    System.out.println(charBuffer.toString());