java转换字符串编码格式的方法

import java.io.UnsupportedEncodingException;

public class ConvertEncodingFormat {

  /**
   * 将一段错误解码的字符串重新解码
   */
  public static String convertEncodingFormat(String str, String formatFrom, String FormatTo) {
    String result = null;
    if (!(str == null || str.length() == 0)) {
      try {
        result = new String(str.getBytes(formatFrom), FormatTo);
      } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
      }
    }
    return result;
  }

  /**
   * test
   */
  public static void main(String[] args) {
　　　　 // utf-8编码
    String str = "你好，少年！";

    // UTF-8编码的byte流强行用iso-8859-1解码，毫无疑问的乱码了
    String str1 = convertEncodingFormat(str, "UTF-8", "iso-8859-1");
    System.out.println(str1);

    // 将str1再转化为byte流,重新用UTF-8解码，乱码问题解决
    String str2 = convertEncodingFormat(str1, "iso-8859-1", "UTF-8");
    System.out.println(str2);
  }

}

import java.io.UnsupportedEncodingException; 
 
/** 
 * 转换字符串的编码 
 */ 
public class ChangeCharset { 
 /** 7位ASCII字符，也叫作ISO646-US、Unicode字符集的基本拉丁块 */ 
 public static final String US_ASCII = "US-ASCII"; 
 
 /** ISO 拉丁字母表 No.1，也叫作 ISO-LATIN-1 */ 
 public static final String ISO_8859_1 = "ISO-8859-1"; 
 
 /** 8 位 UCS 转换格式 */ 
 public static final String UTF_8 = "UTF-8"; 
 
 /** 16 位 UCS 转换格式，Big Endian（最低地址存放高位字节）字节顺序 */ 
 public static final String UTF_16BE = "UTF-16BE"; 
 
 /** 16 位 UCS 转换格式，Little-endian（最高地址存放低位字节）字节顺序 */ 
 public static final String UTF_16LE = "UTF-16LE"; 
 
 /** 16 位 UCS 转换格式，字节顺序由可选的字节顺序标记来标识 */ 
 public static final String UTF_16 = "UTF-16"; 
 
 /** 中文超大字符集 */ 
 public static final String GBK = "GBK"; 
 
 /** 
 * 将字符编码转换成US-ASCII码 
 */ 
 public String toASCII(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, US_ASCII); 
 } 
 /** 
 * 将字符编码转换成ISO-8859-1码 
 */ 
 public String toISO_8859_1(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, ISO_8859_1); 
 } 
 /** 
 * 将字符编码转换成UTF-8码 
 */ 
 public String toUTF_8(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, UTF_8); 
 } 
 /** 
 * 将字符编码转换成UTF-16BE码 
 */ 
 public String toUTF_16BE(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, UTF_16BE); 
 } 
 /** 
 * 将字符编码转换成UTF-16LE码 
 */ 
 public String toUTF_16LE(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, UTF_16LE); 
 } 
 /** 
 * 将字符编码转换成UTF-16码 
 */ 
 public String toUTF_16(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, UTF_16); 
 } 
 /** 
 * 将字符编码转换成GBK码 
 */ 
 public String toGBK(String str) throws UnsupportedEncodingException{ 
 return this.changeCharset(str, GBK); 
 } 
  
 /** 
 * 字符串编码转换的实现方法 
 * @param str 待转换编码的字符串 
 * @param newCharset 目标编码 
 * @return 
 * @throws UnsupportedEncodingException 
 */ 
 public String changeCharset(String str, String newCharset) 
  throws UnsupportedEncodingException { 
 if (str != null) { 
  //用默认字符编码解码字符串。 
  byte[] bs = str.getBytes(); 
  //用新的字符编码生成字符串 
  return new String(bs, newCharset); 
 } 
 return null; 
 } 
 /** 
 * 字符串编码转换的实现方法 
 * @param str 待转换编码的字符串 
 * @param oldCharset 原编码 
 * @param newCharset 目标编码 
 * @return 
 * @throws UnsupportedEncodingException 
 */ 
 public String changeCharset(String str, String oldCharset, String newCharset) 
  throws UnsupportedEncodingException { 
 if (str != null) { 
  //用旧的字符编码解码字符串。解码可能会出现异常。 
  byte[] bs = str.getBytes(oldCharset); 
  //用新的字符编码生成字符串 
  return new String(bs, newCharset); 
 } 
 return null; 
 } 
 
 public static void main(String[] args) throws UnsupportedEncodingException { 
 ChangeCharset test = new ChangeCharset(); 
 String str = "This is a 中文的 String!"; 
 System.out.println("str: " + str); 
 String gbk = test.toGBK(str); 
 System.out.println("转换成GBK码: " + gbk); 
 System.out.println(); 
 String ascii = test.toASCII(str); 
 System.out.println("转换成US-ASCII码: " + ascii); 
 gbk = test.changeCharset(ascii,ChangeCharset.US_ASCII, ChangeCharset.GBK); 
 System.out.println("再把ASCII码的字符串转换成GBK码: " + gbk); 
 System.out.println(); 
 String iso88591 = test.toISO_8859_1(str); 
 System.out.println("转换成ISO-8859-1码: " + iso88591); 
 gbk = test.changeCharset(iso88591,ChangeCharset.ISO_8859_1, ChangeCharset.GBK); 
 System.out.println("再把ISO-8859-1码的字符串转换成GBK码: " + gbk); 
 System.out.println(); 
 String utf8 = test.toUTF_8(str); 
 System.out.println("转换成UTF-8码: " + utf8); 
 gbk = test.changeCharset(utf8,ChangeCharset.UTF_8, ChangeCharset.GBK); 
 System.out.println("再把UTF-8码的字符串转换成GBK码: " + gbk); 
 System.out.println(); 
 String utf16be = test.toUTF_16BE(str); 
 System.out.println("转换成UTF-16BE码:" + utf16be); 
 gbk = test.changeCharset(utf16be,ChangeCharset.UTF_16BE, ChangeCharset.GBK); 
 System.out.println("再把UTF-16BE码的字符串转换成GBK码: " + gbk); 
 System.out.println(); 
 String utf16le = test.toUTF_16LE(str); 
 System.out.println("转换成UTF-16LE码:" + utf16le); 
 gbk = test.changeCharset(utf16le,ChangeCharset.UTF_16LE, ChangeCharset.GBK); 
 System.out.println("再把UTF-16LE码的字符串转换成GBK码: " + gbk); 
 System.out.println(); 
 String utf16 = test.toUTF_16(str); 
 System.out.println("转换成UTF-16码:" + utf16); 
 gbk = test.changeCharset(utf16,ChangeCharset.UTF_16LE, ChangeCharset.GBK); 
 System.out.println("再把UTF-16码的字符串转换成GBK码: " + gbk); 
 String s = new String("中文".getBytes("UTF-8"),"UTF-8"); 
 System.out.println(s); 
 } 
}