调用web服务时，参数中=号变成%3D，导致Base64解码失败。

import java.io.UnsupportedEncodingException;
/**
 * url转码、解码
 */
public class UrlUtil {

    private final static String ENCODE = "UTF-8";
    /** URL 解码*/
    public static String getURLDecoderString(String str) {
        String result = "";
        if (null == str) {
            return "";
        }
        try {
            result = java.net.URLDecoder.decode(str, ENCODE);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return result;
    }

    /** URL 转码*/
    public static String getURLEncoderString(String str) {
        String result = "";
        if (null == str) {
            return "";
        }
        try {
            result = java.net.URLEncoder.encode(str, ENCODE);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
        return result;
    }

}