Here you can find the source of decodeBase64String(String str)
public static String decodeBase64String(String str) throws IOException
//package com.java2s; import sun.misc.BASE64Decoder; import java.io.IOException; public class Main { public static String decodeBase64String(String str) throws IOException { BASE64Decoder encoder = new BASE64Decoder(); return new String(encoder.decodeBuffer(str)); }/*from w w w . jav a 2s .c o m*/ }