java.lang.ClassCastException：java.util.LinkedHashMap无法强制转换为com.ipl.model.User

Question

我有一个REST呼叫

List<User> userList = (List<User>) iplUtil.getResult(user, mongoGetURL);

System.out.println("userList === "+userList);

输出为

 userList = [{_id={$oid=571903dae4b085317593a0d3}, nickName=aa, email=aa, password=aa, userId=1}]

没有合并时间错误.. 但这条线在运行时失败

User u =userList.get(0);

在此行获取异常

    java.lang.ClassCastException: java.util.LinkedHashMap cannot be cast to com.ipl.model.User

和模型为

package com.ipl.model;

import java.io.Serializable;
import java.util.Map;

@SuppressWarnings("serial")
public class User implements Serializable {
    private Map<String, String> _id;
    private String nickName;
    private String email;
    private String password;
    private int userId;


    public User(String nickName,String password) {
        this.nickName=nickName;
        this.password=password;
    }
    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public User() {
        // TODO Auto-generated constructor stub
    }

    public String getNickName() {
        return nickName;
    }

    public void setNickName(String nickName) {
        this.nickName = nickName;
    }

    public Map<String, String> get_id() {
        return _id;
    }

    public void set_id(Map<String, String> _id) {
        this._id = _id;
    }

    public String getPassword() {
        return password;
    }

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

    @Override
    public String toString() {
        return "User [_id=" + _id + ", nickName=" + nickName + ", email=" + email + ", password=" + password
                + ", userId=" + userId + "]";
    }

}

我没有得到任何complie时间错误..为什么它在运行时失败