将字符串的编码格式转换为utf-8

方式一：

/**
 * 将字符串的编码格式转换为utf-8
 *
 * @param str
 * @return Name = new
 * String(Name.getBytes("ISO-8859-1"), "utf-8");
 */
public static String toUTF8(String str) {
	if (isEmpty(str)) {
		return "";
	}
	try {
		if (str.equals(new String(str.getBytes("GB2312"), "GB2312"))) {
			str = new String(str.getBytes("GB2312"), "utf-8");
			return str;
		}
	} catch (Exception exception) {
	}
	try {
		if (str.equals(new String(str.getBytes("ISO-8859-1"), "ISO-8859-1"))) {
			str = new String(str.getBytes("ISO-8859-1"), "utf-8");
			return str;
		}
	} catch (Exception exception1) {
	}
	try {
		if (str.equals(new String(str.getBytes("GBK"), "GBK"))) {
			str = new String(str.getBytes("GBK"), "utf-8");
			return str;
		}
	} catch (Exception exception3) {
	}
	return str;
}

/**
 * 判断是否为空
 *
 * @param str
 * @return
 */
public static boolean isEmpty(String str) {
	// 如果字符串不为null，去除空格后值不与空字符串相等的话，证明字符串有实质性的内容
	if (str != null && !str.trim().isEmpty()) {
		return false;// 不为空
	}
	return true;// 为空
}

方式二：

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);
 }
}