HttpServletRequest request = ServletActionContext.getRequest();

        request.setCharacterEncoding("gb2312");
        String str = request.getParameter("msgContent");
        System.out.println(str);
        System.out
                .println(new String(this.getMsgContent().getBytes(), "utf-8"));
        System.out
                .println(new String(this.getMsgContent().getBytes(), "gb2312"));
        System.out.println(new String(this.getMsgContent().getBytes(), "gbk"));
        System.out.println("可以正常么1：" + this.getMsgContent());// 1
        System.out.println("可以正常么2：" + this.getMsgContent().getBytes());// 2
        System.out.println("可以正常么3：" + this.getMsgContent().getBytes("GB2312"));// 3
        System.out.println("可以正常么4："
                + this.getMsgContent().getBytes("ISO-8859-1"));// 4
        System.out.println("可以正常么5："
                + new String(this.getMsgContent().getBytes()));// 5
        System.out.println("可以正常么6："
                + new String(this.getMsgContent().getBytes(), "GB2312"));// 6
        System.out.println("可以正常么7："
                + new String(this.getMsgContent().getBytes(), "ISO-8859-1"));// 7
        System.out.println("可以正常么8："
                + new String(this.getMsgContent().getBytes("GB2312")));// 8
        System.out
                .println("可以正常么9："
                        + new String(this.getMsgContent().getBytes("GB2312"),
                                "GB2312"));// 9
        System.out.println("可以正常么10："
                + new String(this.getMsgContent().getBytes("GB2312"),
                        "ISO-8859-1"));// 10
        System.out.println("可以正常么11："
                + new String(this.getMsgContent().getBytes("ISO-8859-1")));// 11
        System.out
                .println("====================================12=====================");
        System.out.println("可以正常么12："
                + new String(this.getMsgContent().getBytes("ISO-8859-1"),
                        "GB2312"));// 12
        System.out
                .println("====================================13=====================");
        System.out.println("可以正常么1："
                + new String(this.getMsgContent().getBytes("ISO-8859-1"),
                        "ISO-8859-1"));// 13
        String stra = URLDecoder.decode(this.getMsgContent(), "utf-8");//
        String stra1 = URLDecoder.decode(this.getMsgContent(), "gbk");//
        String stra2 = URLDecoder.decode(this.getMsgContent(), "gb2312");//
        System.out.println(stra);
        System.out.println(stra1);
        System.out.println(stra2);


//运行结果如下：
?????????????
?????????????
?????????????
?????????????
可以正常么1：?????????????
可以正常么2：[B@1cf806b
可以正常么3：[B@11272ec
可以正常么4：[B@36fc18
可以正常么5：?????????????
可以正常么6：?????????????
可以正常么7：?????????????
可以正常么8：?????????????
可以正常么9：?????????????
可以正常么10：?????????????
可以正常么11：?????????????
====================================12=====================
可以正常么12：?????????????
====================================13=====================
可以正常么1：?????????????
?????????????
?????????????
?????????????