java字符转码的三种方法总结及实例

java字符转码:三种方法

转码成功的前提:解码后无乱码

转码流程:文件(gbk)-->解码-->编码--->文件(utf-8)

注:如有问题请留言

下面具体的实例

 方法一:Java.lang.String

//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);
  }

方法二:java.io.InputStreamReader/OutputStreamWriter:桥转换 

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();
    }
  }
}

方法三:java.nio.Charset

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();
    }
  } 

}

感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！