Mybatis查询结果ResultMap的继承

需求：在查询用户表的同时，关联角色表查出角色名称(假设每个用户只有一个角色)

//用户类
public class User {
	
    private String id;
	
    private String name;
    
    private String roleId;

	public String getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	public String getRoleId() {
		return roleId;
	}

	public void setRoleId(String roleId) {
		this.roleId = roleId;
	}
    
}
//角色类
public class Role {
	
	private String id;
	
	private String name;

	public String getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
	
}
//接收查询结果的用户类
public class UserView extends User{

    private String roleName;

    public String getRoleName() {
		return roleName;
	}

	public void setRoleName(String roleName) {
		this.roleName= roleName;
	}
}

XML文件

  
    
    
    
  

 
    
 
    
 
    select
        u.id,
        u.name,
        u.role_id,
        r.name as role_name
    from user u
    left join role r
    on u.role_id = r.id