springMVC的controller接受ajax的post請求

剛剛學習SpringMVC ，ajax發送post請求出現了一些問題，記錄一下。

@RequestBody 接收客戶端發送的ajax請求中的json字符串,后端自動轉換為User對象

前端

var username = $('#username').val();
var password = $('#password').val();
var data = {username : username , password: password};
if(username != "" && password != ""){
    $.ajax({
        type: "post",
        url: "${pageContext.request.contextPath}/user/login",
        dataType: "json",
        contentType: "application/json",//設置類型為json
        data: JSON.stringify(data),//數據要經過這個進行處理轉為json字符串
        //JSON.stringify() 方法用於將 JavaScript 值轉換為 JSON 字符串
        success: function (msg) {
            //處理
        },
        error:function () {
            alert("錯誤")
        }
    });
}else {
    alert('請輸入賬號密碼')
}

controller

    @PostMapping(value = "/login")
    @ResponseBody
    public String login(@RequestBody User pass_user,HttpSession session){
        User user = userService.login(pass_user.getUsername(), pass_user.getPassword());

        if (user != null) {
            session.setAttribute("user",user);
            return "1";
        }
        return "0";
    }

也可以用map接收

    @PostMapping(value = "/login")
    @ResponseBody
    public String login(@RequestBody Map<String,Object> pass_user,HttpSession session){
        User user = userService.login(pass_user.get("username").toString(), pass_user.get("password").toString());

        if (user != null) {
            session.setAttribute("user",user);
            return "1";
        }
        return "0";
    }

json字符串和JavaBean對象互相轉換的過程中，需要使用jackson的jar包

maven加入的依賴

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.11.0</version>
</dependency>