Java工具箱之字符编码工具类

Posted 2022-06-20 Trigl

涉及到文件的字符编码问题一般需要知道两个内容：
1、文件本身的字符编码是什么？
2、如何将文件的字符编码集转换为另一种？
这个工具类就解决这两个问题

package com.trigl.util;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.URLDecoder;
import java.net.URLEncoder;

/**
 * 字符编码工具类
 * @author 白鑫
 *  2016年7月26日 下午7:18:01
 */
public class EncodingUtil 

    /**
     * 获取指定文件的字符编码类型
     * @param filePath
     * @return
     */
    @SuppressWarnings("resource")
    public static String getFileCharset(String filePath) 
        String charset = "GBK";
        byte[] f3b = new byte[3];
        try 
            boolean check = false;
            BufferedInputStream bis = new BufferedInputStream(
                    new FileInputStream(filePath));
            bis.mark(0);
            int read = bis.read(f3b, 0, 3);
            if (read == -1) 
                return charset;
             else if (f3b[0] == (byte) 0xFF && f3b[1] == (byte) 0xFE) 
                charset = "UTF-16LE";
                check = true;
             else if (f3b[0] == (byte) 0xEF && f3b[1] == (byte) 0xBB
                    && f3b[2] == (byte) 0xBF) 
                charset = "UTF-8";
                check = true;
            
            bis.reset();
            if (!check) 
                while ((read = bis.read()) != -1) 
                    if (read >= 0xF0)
                        break;

                    if (0x80 <= read && read <= 0xBF)
                        break;// GBK

                    if (0xC0 <= read && read <= 0xDF) 
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF)
                            continue;
                        else
                            break;

                     else if (0xE0 <= read && read <= 0xEF) 
                        read = bis.read();
                        if (0x80 <= read && read <= 0xBF) 
                            read = bis.read();
                            if (0x80 <= read && read <= 0xBF) 
                                charset = "UTF-8";
                                break;
                             else
                                break;
                         else
                            break;
                    
                
            
            bis.close();
         catch (Exception e) 
            e.printStackTrace();
        
        return charset;
    

    /**
     * 转换文件字符编码
     * 步骤是先读取源文件的内容，存放到StringBuffer里面，
     * 然后删除源文件，再重新new一个与源文件名一样的文件，再以另一种编码形式存放。
     * @param path 文件绝对路径
     * @param desCharset 想要转换的编码
     * @throws Exception
     */
    public static void convertEncoding (String path,String desCharset) throws Exception 
        File srcFile = new File(path);
        String srcCharset = getFileCharset(path); // 获取文件本来的字符编码
        System.out.println(path + "的字符编码是" + srcCharset + "，要转成的字符编码是" + desCharset);
        if(srcCharset.equalsIgnoreCase(desCharset)) 
            System.out.println("编码相同，无需转换");
         else 
            System.out.println("编码不同，需要转换");
            InputStream in = new FileInputStream(path);
            BufferedReader br = new BufferedReader(new InputStreamReader(in, srcCharset));
            StringBuffer sb = new StringBuffer();
            String s1;
            while((s1 = br.readLine()) != null) 
                String s = URLEncoder.encode(s1, desCharset);
                sb.append(s + "\\r\\n"); // 一行+回车
            
            br.close();
            srcFile.delete(); // 删除原来的文件
            // 重新以新编码写入文件并返回值
            File desFile = new File(path); // 重新建原来的文件
            desFile.createNewFile();
            OutputStream out = new FileOutputStream(desFile);
            OutputStreamWriter writer = new OutputStreamWriter(out, desCharset);
            BufferedWriter bw = new BufferedWriter(writer);
            bw.write(URLDecoder.decode(sb.toString(), desCharset));
            bw.flush(); // 刷新到文件中
            bw.close();
        
    

    public static void main(String[] args) 
        try 
            String charset = getFileCharset("C:/Users/三浪/Desktop/99701200000_KFDB_DSMC_0402_20160304_I_4321_0001.XML");
            System.out.println(charset);
            convertEncoding("C:/Users/三浪/Desktop/1.txt", "utf-16");
         catch (Exception e) 
            // TODO Auto-generated catch block
            e.printStackTrace();
        
    

---

Men were born to be suffering, the pain of struggle, or the pain of regret?