前端传json对象(包含json数组在里面)的时候,后台为Java,用SSM时候如何接收

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前端JS代码 如下:

var url = "web";
var postdata = 
"history":[
                          
                             "time":"2017-10-18 10:10:10", //time 字段:时间
                            "option":"human" //option 字段:用户human,机器machine
                           ,
                          
                            "time":"2017-10-19 99:99:99",
                            "option":"machine"
                           
                         ],
               "openid":"abcdefghijklmn",  
               "type":"家庭"
              ;
$.ajax(
type:"POST",

url:url,

//JSON.stringify(),将postdata对象转换成字符串形式
data:"postdata":JSON.stringify(postdata), //调用ajax的时候,data属性必须这样写。必须
dataType:"json",
success:function(data)




);

Java代码如下

//@RequestParam("postdata") 这句话是关键,跟前端的 data:"postdata":JSON.stringify(postdata) 对应,属性名要一致

@RequestMapping("/addQuestionIntelligence")
public @ResponseBody ResponseResult addQuestionIntelligence(@RequestParam("postdata") String postdata, HttpServletRequest request,HttpSession session)throws Exception

org.json.JSONObject json = new org.json.JSONObject(postdata);



【前端向后端传 

问题背景:
我要在一个表单里同时一次性提交多名乘客的个人信息到SpringMVC,前端html和SpringMVC Controller里该如何处理?

    第1种方法:表单提交,以字段数组接收;
    第2种方法:表单提交,以BeanListModel接收;
    第3种方法:将Json对象序列化成Json字符串提交,以List接收;
    第4种方法:将表单对象序列化成Json字符串提交,以List接收;
    第4种方法其实是第3种方法的升级,就是将表单转成Json对象,再转成Json字符串提交;
    然而,第4种方法还不支持含有多选控件表单的提交,故应该还有第5种加强版的方法。

以上4种方法都共用同一个User实体类,代码如下:

    public class User
     
        private Integer id;
        private String name;
        private String pwd;
     
        @Override
        public String toString()
            return "User" +
                    "id=" + id +
                    ", name=‘" + name + ‘\‘‘ +
                    ", pwd=‘" + pwd + ‘\‘‘ +
                    ‘‘;
       
        // .......后面还有getter、setter方法,省略了
    

第1种方法:表单提交,以字段数组接收
HTML代码如下:

    <form action="/user/submitUserList_1" method="post">
            ID:<input type="text" name="id"><br/>
            Username:<input type="text" name="name"><br/>
            Password:<input type="text" name="pwd"><br/><br/>
     
            ID:<input type="text" name="id"><br/>
            Username:<input type="text" name="name"><br/>
            Password:<input type="text" name="pwd"><br/><br/>
            <input type="submit" value="submit">
        </form>

Java代码如下:

    @RequestMapping(value = "/submitUserList_1", method =RequestMethod.POST)
        @ResponseBody
        public String submitUserList_1(HttpServletResponse response,Integer[] id, String[] name, String[] pwd)
                                throws Exception
            String result = "";
            if(id == null || id.length <= 0) return "No any ID.中文";
            List<User> userList = new ArrayList<User>();
            for (int i = 0; i < id.length; i++ )
                User user = new User();
                user.setId(id[i]);
                user.setName(name[i]);
                user.setPwd(pwd[i]);
                userList.add(user);
           
            result = this.showUserList(userList);
            return result;
       

第2种方法:表单提交,以BeanListModel接收
HTML代码如下:

    <form action="/user/submitUserList_2" method="post">
            ID:<input type="text" name="users[0].id"><br/>
            Username:<input type="text" name="users[0].name"><br/>
            Password:<input type="text" name="users[0].pwd"><br/><br/>
     
            ID:<input type="text" name="users[2].id"><br/>
            Username:<input type="text" name="users[2].name"><br/>
            Password:<input type="text" name="users[2].pwd"><br/><br/>
            <input type="submit" value="Submit">
        </form>

Java代码:
除了刚才公用的User类,还要封装一个User的容器类UserModel:

    public class UserModel
        private List<User> users;
     
        public List<User> getUsers()
            return users;
       
     
        public void setUsers(List<User> users)
            this.users = users;
       
     
        public UserModel(List<User> users)
            super();
            this.users = users;
       
     
        public UserModel()
            super();
       
     
   

SpringMVC Controller方法:

    @RequestMapping(value = "/submitUserList_2", method =RequestMethod.POST)
        @ResponseBody
        public String submitUserList_2(UserModel users)
                throws Exception
            String result = "";
            List<User> userList = users.getUsers();
            if(userList == null || userList.size() <= 0) return "No any ID.中文";
            result = this.showUserList(userList);
            return result;
       

第3种方法:将Json对象序列化成Json字符串提交,以List接收
HTML代码:

    <head>
        <title>submitUserList_3</title>
        <meta http-equiv="content-type" content="text/html; charset=utf-8">
        <script language="javascript" src="/js/jquery.min.js" ></script>
        <script language="JavaScript" src="/js/jquery.json.min.js" ></script>
        <script type="text/javascript" language="JavaScript">
            function submitUserList_3() alert("ok");
                var customerArray = new Array();
                customerArray.push(id: "1", name: "李四", pwd: "123");
                customerArray.push(id: "2", name: "张三", pwd: "332");
                $.ajax(
                    url: "/user/submitUserList_3",
                    type: "POST",
                    contentType : ‘application/json;charset=utf-8‘, //设置请求头信息
                    dataType:"json",
                    //data: JSON.stringify(customerArray),    //将Json对象序列化成Json字符串,JSON.stringify()原生态方法
                    data: $.toJSON(customerArray),            //将Json对象序列化成Json字符串,toJSON()需要引用jquery.json.min.js
                    success: function(data)
                        alert(data);
                    ,
                    error: function(res)
                        alert(res.responseText);
                   
                );
           
        </script>
    </head>
     
    <body>
        <h1>submitUserList_3</h1>
        <input id="submit" type="button" value="Submit" onclick="submitUserList_3();">
    </body>

Java代码:

    @RequestMapping(value = "/submitUserList_3", method =RequestMethod.POST)
        @ResponseBody
        public String submitUserList_3(@RequestBody List<User> users)
                throws Exception
            String result = "";
            if(users == null || users.size() <= 0) return "No any ID.中文";
            result = this.showUserList(users);
            return result;
       

第4种方法:将表单对象序列化成Json字符串提交,以List接收
HTML代码:

    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
            "http://www.w3.org/TR/html4/loose.dtd">
    <html>
    <head>
        <title>submitUserList_4</title>
        <meta http-equiv="content-type" content="text/html; charset=utf-8">
        <script language="JavaScript" src="/js/jquery.min.js" ></script>
        <script type="text/javascript" language="JavaScript">
            //将表单序列化成json格式的数据(但不适用于含有控件的表单,例如复选框、多选的select)
            (function($)
                $.fn.serializeJson = function()
                    var jsonData1 = ;
                    var serializeArray = this.serializeArray();
                    // 先转换成"id": ["12","14"], "name": ["aaa","bbb"], "pwd":["pwd1","pwd2"]这种形式
                    $(serializeArray).each(function ()
                        if (jsonData1[this.name])
                            if ($.isArray(jsonData1[this.name]))
                                jsonData1[this.name].push(this.value);
                            else
                                jsonData1[this.name] = [jsonData1[this.name], this.value];
                           
                        else
                            jsonData1[this.name] = this.value;
                       
                    );
                    // 再转成["id": "12", "name": "aaa", "pwd":"pwd1","id": "14", "name": "bb", "pwd":"pwd2"]的形式
                    var vCount = 0;
                    // 计算json内部的数组最大长度
                    for(var item in jsonData1)
                        var tmp = $.isArray(jsonData1[item]) ? jsonData1[item].length : 1;
                        vCount = (tmp > vCount) ? tmp : vCount;
                   
     
                    if(vCount > 1)
                        var jsonData2 = new Array();
                        for(var i = 0; i < vCount; i++)
                            var jsonObj = ;
                            for(var item in jsonData1)
                                jsonObj[item] = jsonData1[item][i];
                           
                            jsonData2.push(jsonObj);
                       
                        return JSON.stringify(jsonData2);
                    else
                        return "[" + JSON.stringify(jsonData1) + "]";
                   
                ;
            )(jQuery);
     
            function submitUserList_4() alert("ok");
                var jsonStr = $("#form1").serializeJson();
                //console.log("jsonStr:\r\n" + jsonStr);
                //alert(jsonStr);
                $.ajax(
                    url: "/user/submitUserList_4",
                    type: "POST",
                    contentType : ‘application/json;charset=utf-8‘, //设置请求头信息
                    dataType:"json",
                    data: jsonStr,
                    success: function(data)
                        alert(data);
                    ,
                    error: function(res)
                        alert(res.responseText);
                   
                );
           
        </script>
    </head>
     
    <body>
        <h1>submitUserList_4</h1>
        <form id="form1">
            ID:<input type="text" name="id"><br/>
            Username:<input type="text" name="name"><br/>
            Password:<input type="text" name="pwd"><br/><br/>
     
            ID:<input type="text" name="id"><br/>
            Username:<input type="text" name="name"><br/>
            Password:<input type="text" name="pwd"><br/><br/>
            <input type="button" value="submit" onclick="submitUserList_4();">
        </form>
    </body>
    </html>

Java代码:

    @RequestMapping(value = "/submitUserList_4", method =RequestMethod.POST)
        @ResponseBody
        public String submitUserList_4(@RequestBody List<User> users)
                throws Exception
            String result = "";
            if(users == null || users.size() <= 0) return "No any ID.中文";
            result = this.showUserList(users);
            return result;
       

总结:
第1、2种方法其实都有一个共同的BUG:假如提交三条记录时,前面两条记录的某些字段不填值的话,在SpringMVC里接收不准确了。而且,每2种方法在HMTL中需要给name属性添加[下标],如果下标有跨度的话(比如第一组控件下标是0,第二组下标是2),那么SpringMVC里其实的是0到2三个对象的,默认下标是1的那个对象全为null值。
第3、4种方法最实用。

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