前后端数据传输问题:spring/ajax

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前后端数据传输问题:spring/ajax

ajax调用接口415错误

前后端数据传输问题:spring/ajax

  • ajax调用接口415错误的时候，很可能是你忘记在ajax中加入
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contentType: "application/json;charset=UTF-8"

下方有完整实例。

问题描述

参数有问题,不能解析成json对象

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Caused by: com.fasterxml.jackson.core.JsonParseException: Unrecognized token 'name': was expecting ('true', 'false' or 'null')

解决方案

ajax提交添加下面两行代码

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contentType:'application/json;charset=utf-8'
data:JSON.stringify(数据)

补充说明

后端如果用 SpringMVC 的@RequestBody 注解，则只能 JSON 对象的字符串，不能接收 JSON 对象，用 JSON.stringify(data) 的方式将对象变成字符串，同时 ajax请求也要指定 dataType: “json”,contentType:”application/json” ，这样就能用@RequestBody注解绑定对象或者List集合.

完整登录实例：

前台：

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<!DOCTYPE html>
<html>
<head>
<title>login.html</title>
<meta charset="utf-8">
</head>

<script type="text/javascript" src="jquery-3.5.1.min.js"></script>
<script type="text/javascript">
    $(function(){
        $("#submit").click(function(){
        var url = "http://localhost:8080/api/login";
        var users = {"username":$("input[type='text']").val(), "password":$("input[type='password']").val()};

        $.ajax({
                "url" : url,
                "data" :users,
                "type" : "post",
                dataType: "json",
                data:JSON.stringify(users),
                contentType: "application/json;charset=UTF-8",
                "success" : function(data) {
                    // 参数为json类型的对象
                    alert(data.id)
                },
                "error" : function() {
                    alert("用户名或者密码错误");
                }
            });

        });
    });
</script>

<body>
    <form action="#">
        username:<input type="text" name="username"><br>
        password:<input type="password" name="password"><br>
        <input type="button" value="submit" id="submit">
    </form>
</body>
</html>

后台：

LoginController 类：

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import com.felixcai.movie.api.domain.User;
import com.felixcai.movie.api.repository.LoginRepository;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiImplicitParam;
import io.swagger.annotations.ApiImplicitParams;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletResponse;

/**
 * @author  蔡济阳 FelixCai
 */
@CrossOrigin
@Api(value="用户登录controller",tags={"用户登录操作接口"})
@Controller
@RequestMapping(value = "/api")
public class LoginController {

    @Autowired
    LoginRepository loginRepository;

    @RequestMapping(value = "/login",method = RequestMethod.POST)
    @ResponseBody
    public User userLogin(HttpServletResponse response, @RequestBody User users) {
        User user = loginRepository.login(users.getUsername(), users.getPassword());
        if (user == null) {
            return new User(0,"404","404");
        }
        return user;
    }
}

LoginRepository 类：

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import com.felixcai.movie.api.domain.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;
import org.springframework.data.jpa.repository.Query;

public interface LoginRepository extends JpaRepository<User,Integer>, JpaSpecificationExecutor<User> {
    //登录
    @Query(value = "select * from user where username = ? and password = ?",nativeQuery = true)
    User login(String username,String password);
}

User 类：

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import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import javax.persistence.Entity;
import javax.persistence.Id;

/**
 * @author  蔡济阳 FelixCai
 */

@Entity
public class User {

    @Id
    private Integer id;

    private String username;
    private String password;

    public User() {
    }

    public User(Integer id, String username, String password) {
        this.id = id;
        this.username = username;
        this.password = password;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}