java - 当我用户 Angular 发布数据时，我在 Spring Controller 中得到空值

Question

我使用 Angularjs 将数据发送到 spring Controller 。

像这样。

var user ={
    "userID" : "1",
    "username" : "hello",
    "password" : "123456"
};
console.log(user);
var response = $http.post("/login/signup",user);
response.success(function (data) {
    alert("success");
    alert(data);
});
response.error(function (data) {
    alert("error");
    alert(data);
});

我的模型

public class User {
    private long userID;
    private String username;
    private String password;

    public User(){

    }

    public User(long userID, String username, String password) {
        this.userID = userID;
        this.username = username;
        this.password = password;
    }


    public long getUserID() {
        return userID;
    }

    public void setUserID(long userID) {
        this.userID = userID;
    }

    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;
    }
}

还有我的 Controller 。

@Controller
@RequestMapping(value = "/login")
public class LoginController {

    @RequestMapping(value = "/signup",method = RequestMethod.POST)
    public String signUp(User user){
        String username = user.getUsername();// NULL!!
        System.out.println(username);
        return "login";
    }

}

我得到这样的空用户。

如果我将 @RequestBody 添加到我的 Controller 。我什至无法进入 Controller 并出现异常。

@RequestMapping(value = "/signup",method = RequestMethod.POST,produces = {MediaType.APPLICATION_JSON_VALUE})
    public String signUp(@RequestBody User user){
        String username = user.getUsername();
        System.out.println(username);
        return "login";
    }

异常

The server refused this request because the request entity is in a format not supported by the requested resource for the requested method.

Answer 1

当您将数据发布到服务器时，您可能需要在请求 header 中设置 Content-Type: application/json。

还可以使用:

@RequestMapping(value = "/signup",method = RequestMethod.POST,consumes = MediaType.APPLICATION_JSON_VALUE)

安装:

@RequestMapping(value = "/signup",method = RequestMethod.POST,produces = {MediaType.APPLICATION_JSON_VALUE})

编辑

有时(我不确定什么时候)，MappingJackson2HttpMessageConverter 不会向负责将请求参数转换为模型 bean 的 spring 上下文注册。如果未注册，手动注册可能会解决问题。