java取汉字区位码 java 获取字符串编码

public 
 
       String encode = "GB2312";
         
            //  将str转换成gb2312编码的字节，并转换成gb2312编码的字符串
             if (str.equals(new String(str.getBytes(encode), encode))) {
                 String s = encode;
                 return s;
             }
         } catch (Exception exception) {
         }
         encode = "ISO-8859-1";
         try {
             if (str.equals(new String(str.getBytes(encode), encode))) {
                 String s1 = encode;
                 return s1;
             }
         } catch (Exception exception1) {
         }
         encode = "UTF-8";
         try {
             if (str.equals(new String(str.getBytes(encode), encode))) {
                 String s2 = encode;
                 return s2;
             }
         } catch (Exception exception2) {
         }
         encode = "GBK";
         try {
             if (str.equals(new String(str.getBytes(encode), encode))) {
                 String s3 = encode;
                 return s3;
             }
         } catch (Exception exception3) {
         }
         return "";