mybaits 中的配置，应和查询到的参数 一一对应，才可以映射到pojo类中

在 mybaits 的mapper 配置应该和类中的参数一一对应

import java.io.Serializable;public class User implements Serializable{private int id;private String name;private int age;<strong>private int roleId;//和hibernate的不同点，就是需要添加查询到的参数，</strong>private Role role;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public int getRoleId() {return roleId;}public void setRoleId(int roleId) {this.roleId = roleId;}public Role getRole() {return role;}public void setRole(Role role) {this.role = role;}}

import java.io.Serializable;public class Role  implements Serializable{private int id;private String name;public int getId() {return id;}public void setId(int id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}}