ajax jquery 向服务端发请求中文乱码

1 现象

浏览器客户端页面charset是GBK

<meta http-equiv="content-type" content="text/html; charset=GBK" />

服务端收到乱码

String roleName = request.getParameter(ROLE_NAME_PARAM);

获得的编码是UTF-8 

String charset = request.getCharacterEncoding();

2 修改后，解决乱码

    jQuery.ajax({
        url: path,
        type: "POST",
        dataType:'json',
        contentType: "application/x-www-form-urlencoded; charset=utf-8", // 增加这一行
	data:{'type' : type, 'roleName' : roleName, 'roleId' : roleId},
        success:function(json) {
         
        },
        error:function(er){
           var err = eval("(" + xhr.responseText + ")");
           alert(err.Message);
        }
    });