java字符转码的三种方法总结及实例

//用于解码的构造器: String(byte[] bytes, int offset, int length, String charsetName)  String(byte[] bytes, String charsetName)   用于编码的方法: byte[] getBytes(String charsetName) //使用指定字符集进行编码  byte[] getBytes() //使用系统默认字符集进行编码 

public void convertionString() throws UnsupportedEncodingException{     String s = "清山";     byte[] b = s.getBytes("gbk");//编码     String sa = new String(b, "gbk");//解码:用什么字符集编码就用什么字符集解码     System.out.println(sa);          b = sa.getBytes("utf-8");//编码     sa = new String(b, "utf-8");//解码     System.err.println(sa);   } 

package com.qingshan.io;  import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.UnsupportedEncodingException;  /**  * <pre>  * 使用java.io桥转换:对文件进行转码  * </pre>  * <hr Color="green" ></hr>  * 2012 Qingshan Group 版权所有  * <hr Color="green" ></hr>  * @author thetopofqingshan  * @version 1.0.0  * @since  JDK 1.5  * @date  2012-4-28  */ public class CharsetConvertion {   private FileInputStream fis;// 文件输入流:读取文件中内容   private InputStream is;   private InputStreamReader isr;   private OutputStream os;   private OutputStreamWriter osw;//写入   private char[] ch = new char[1024];   public void convertionFile() throws IOException{     is = new FileInputStream("C:/项目进度跟踪.txt");//文件读取     isr = new InputStreamReader(is, "gbk");//解码     os = new FileOutputStream("C:/项目进度跟踪_utf-8.txt");//文件输出     osw = new OutputStreamWriter(os, "utf-8");//开始编码     char[] c = new char[1024];//缓冲     int length = 0;     while(true){       length = isr.read(c);       if(length == -1){         break;       }       System.out.println(new String(c, 0, length));       osw.write(c, 0, length);       osw.flush();     }        }      public void convertionString() throws UnsupportedEncodingException{     String s = "清山集团";     byte[] b = s.getBytes("gbk");//编码     String sa = new String(b, "gbk");//解码:用什么字符集编码就用什么字符集解码     System.out.println(sa);          b = sa.getBytes("utf-8");//编码     sa = new String(b, "utf-8");//解码     System.err.println(sa);   }          /**    * <pre>    * 关闭所有流    * </pre>    *    */   public void close(){     if(isr != null){       try {         isr.close();       } catch (IOException e) {         e.printStackTrace();       }     }     if(is != null){       try {         is.close();       } catch (IOException e) {         // TODO Auto-generated catch block         e.printStackTrace();       }     }          if(osw != null){       try {         osw.close();       } catch (IOException e) {         // TODO Auto-generated catch block         e.printStackTrace();       }     }          if(os != null){       try {         os.close();       } catch (IOException e) {         // TODO Auto-generated catch block         e.printStackTrace();       }     }   }      /**    * <pre>    * 用io读取文件内容    * </pre>    *    * @throws IOException    *       读取过程中发生错误    *    */      /**    * <pre>    *    * </pre>    * @param path    * @param charset    * @throws IOException    *    */   public void read(String path, String charset) throws IOException {     fis = new FileInputStream(path);     isr = new InputStreamReader(fis, charset);     while (fis.available() > 0) {       int length = isr.read(ch);        System.out.println(new String(ch));     }   }       public static void main(String[] args) {     try {       CharsetConvertion cc = new CharsetConvertion();       cc.convertionFile();       cc.convertionString();       cc.close();     } catch (IOException e) {       e.printStackTrace();     }   } } 

package com.qingshan.nio;  import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStreamReader; import java.nio.ByteBuffer; import java.nio.CharBuffer; import java.nio.channels.FileChannel; import java.nio.charset.Charset; import java.nio.charset.CharsetDecoder; import java.nio.charset.CharsetEncoder;  /**  * <pre>  * 使用nio中的Charset转换字符:整个流程是文件读取-->byte-->解码(正确)-->编码--->byte-->写入文件  * </pre>  * <hr Color="green" >  * </hr>  * 2012 Qingshan Group 版权所有  * <hr Color="green" >  * </hr>  *  * @author thetopofqingshan  * @version 1.0.0  * @since JDK 1.5  * @date 2012-4-27  */ public class CharsetConvertion {   private FileInputStream fis;// 文件输入流:读取文件中内容   private FileChannel in;// 文件通道:双向,流从中而过   private FileChannel out;// 文件通道:双向,流从中而过   private FileOutputStream fos;// 文件输出流:向文件中写入内容   private ByteBuffer b = ByteBuffer.allocate(1024 * 3);// 设置缓存区的大小   private Charset inSet;// 解码字符集   private Charset outSet;// 编码字符集   private CharsetDecoder de;// 解码器   private CharsetEncoder en;// 编码器   private CharBuffer convertion;// 中间的字符数据   private ByteBuffer temp = ByteBuffer.allocate(1024 * 3);// 设置缓存区的大小:临时   private byte[] by = new byte[1024];   private InputStreamReader isr;   private char[] ch = new char[1024];    /**    * <pre>    *    * </pre>    *    * @param src    * @param dest    * @throws IOException    *    */   public void convertionFile_nio(String src, String dest) throws IOException {     fis = new FileInputStream(src);     in = fis.getChannel();     fos = new FileOutputStream(dest);     out = fos.getChannel();     inSet = Charset.forName("gbk");     outSet = Charset.forName("utf-8");     de = inSet.newDecoder();     en = outSet.newEncoder();     while (fis.available() > 0) {       b.clear();// 清除标记       in.read(b); // 将文件内容读入到缓冲区内:将标记位置从0-b.capacity(),             // 读取完毕标记在0-b.capacity()之间       b.flip();// 调节标记,下次读取从该位置读起       convertion = de.decode(b);// 开始编码        temp.clear();// 清除标记       temp = en.encode(convertion);       b.flip(); // 将标记移到缓冲区的开始,并保存其中所有的数据:将标记移到开始0       out.write(temp); // 将缓冲区内的内容写入文件中:从标记处开始取出数据     }   }    /**    * <pre>    * 测试转码是否成功, 指定字符集读取文件    * </pre>    *    * @param src    *      被复制文件全路径    * @param charset 解码字符集    *    * @throws IOException 读取过程中的发生的异常    *    */   public void read(String path, String charset) throws IOException {     fis = new FileInputStream(path);     isr = new InputStreamReader(fis, charset);     while (fis.available() > 0) {       int length = isr.read(ch);       System.out.println(new String(ch));     }   }    /**    * <pre>    * 关闭所有流或通道    * </pre>    *    */   public void close() {     try {       if (in != null) {         in.close();       }     } catch (IOException e) {       e.printStackTrace();     }      try {       if (out != null) {         out.close();       }     } catch (IOException e) {       e.printStackTrace();     }      try {       if (fis != null) {         fis.close();       }     } catch (IOException e) {       e.printStackTrace();     }      try {       if (fos != null) {         fos.close();       }     } catch (IOException e) {       e.printStackTrace();     }   }    public static void main(String[] args) {     CharsetConvertion n = new CharsetConvertion();     try {        n.convertionFile_nio("C:/项目进度跟踪.txt", "C:/nio_write.txt"); //     n.read("C:/nio_write.txt", "utf-8");// 正确       // n.read("C:/nio_write.txt", "gbk");//乱码     } catch (IOException e) {       e.printStackTrace();     } finally {       n.close();     }   }  }