用java修改文件的编码

1、将本地的文件转换成另外一种编码输出，主要逻辑代码如下：

 /**
     * 将本地文件以哪种编码输出
     * @param inputfile 输入文件的路径
     * @param outfile 输出文件的路径
     * @param code 输出文件的编码
     * @throws IOException
     */
    public  void convert(String inputfile,String outfile,String code) throws IOException {
        StringBuffer sb = new StringBuffer();
        //得到当前文件的编码
        String ch=getCharset(inputfile);
        InputStreamReader isr=null;
        OutputStreamWriter osw =null;
        //根据当前文件编码进行解码
        if(ch.equals("UTF8")){
            isr= new InputStreamReader(new FileInputStream(inputfile), "UTF-8");    
        }else if(ch.equals("Unicode")){
            isr= new InputStreamReader(new FileInputStream(inputfile), "Unicode");    
        }else {
            isr= new InputStreamReader(new FileInputStream(inputfile), "GB2312");    
        }
        //将字符串存入StringBuffer中
        BufferedReader br = new BufferedReader(isr);        
        String line = null;
        while ((line = br.readLine()) != null) {
            sb.append(line + "
");
        }        
        br.close();
        isr.close();

        //以哪种方式写入文件
        if("UTF-8".equals(code)){
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "UTF-8");
        }else if("GB2312".equals(code)){
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "GB2312");
        }else if("Unicode".equals(code)){
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "Unicode");
        }else{
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "UTF-8");
        }
        BufferedWriter bw = new BufferedWriter(osw);
        bw.write(sb.toString());
        bw.close();
        osw.close();
    }

/**
     * 根据文件路径判断编码
     * @param str
     * @return
     * @throws IOException
     */
    private String getCharset(String str) throws IOException{ 
        BytesEncodingDetect s = new BytesEncodingDetect();   
        String code = BytesEncodingDetect.javaname[s.detectEncoding(new File(str))];  
        return code;  
    } 

2、将远程的文件转换成自己想要的编码，然后写入本地

/**
     * 将远程文件以哪种编码输出到本地
     * @param fileurl 远程文件的URL
     * @param outfile 输出文件的路径
     * @param code 以哪种编码输出
     * @throws Exception
     */
    public void Remote(String fileurl,String outfile,String code) throws Exception{ 
        //        String str="http://172.18.1.103:8080/kms/text.txt";
        URL url =new URL(fileurl);
        HttpURLConnection urlCon = (HttpURLConnection)url.openConnection();
        //设置连接超时和读取超时
        urlCon.setConnectTimeout(5000);
        urlCon.setReadTimeout(5000);
        //得到远程文件的编码
        String ch=getCharset_Remote(fileurl);
        //文件写入流
        OutputStreamWriter osw =null;
        BufferedReader br=null;
        //将字符串保存到临时的StringBuffer中
        StringBuffer sb = new StringBuffer();
        if(ch.equals("UTF8")){
            br =new BufferedReader(new InputStreamReader( urlCon.getInputStream(),"UTF-8"));
            String line = null;
            while ((line = br.readLine()) != null) {
                sb.append(line + "
");
            }
        }
        else if(ch.equals("Unicode")){
            br =new BufferedReader(new InputStreamReader( urlCon.getInputStream(),"Unicode"));
            String line = null;
            while ((line = br.readLine()) != null) {
                sb.append(line + "
");
            }
        }
        else{
            br =new BufferedReader(new InputStreamReader( urlCon.getInputStream(),"GB2312"));
            String line = null;
            while ((line = br.readLine()) != null) {
                sb.append(line + "
");
            }
        }
        br.close();    

        //以哪种方式写入文件
        if("UTF-8".equals(code)){
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "UTF-8");
        }else if("GB2312".equals(code)){
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "GB2312");
        }else if("Unicode".equals(code)){
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "Unicode");
        }else{
            osw = new OutputStreamWriter(new FileOutputStream(outfile), "UTF-8");
        }
        BufferedWriter bw = new BufferedWriter(osw);
        bw.write(sb.toString());
        bw.close();
        osw.close();
    } 

/**
     * 根据文件路径判断远程文件编码
     * @param str
     * @return
     * @throws IOException
     */
    private String getCharset_Remote(String str) throws IOException{  
        URL url =new URL(str);
        BytesEncodingDetect s = new BytesEncodingDetect();   
        String fileCode = BytesEncodingDetect.javaname[s.detectEncoding(url)];  
        return fileCode;
    }

3、测试代码：

package com.zhang.test;

public class test {
    public static void main(String[] args) {
        String inputfile="D:/gbk.txt";
        String outfile="D:/utf8.txt";
        String outfileurl="D:/utf8url.txt";
        String fileurl="http://127.0.0.1:8080/jsp/gbk.txt";
//        String file="D:/unicode.txt";
        Convert_Code code=new Convert_Code();
        try {
            code.convert(inputfile,outfile,"UTF-8");
            code.Remote(fileurl, outfileurl, "UTF-8");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

注意：这两个方法引用了BytesEncodingDetect.java文件

此案例的下载链接：http://download.csdn.net/detail/u013865056/9908100