Mybatis查询结果ResultMap的继承

￡神魔★判官ぃ 2021-06-24 16:09 481阅读 0赞

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

<resultMap id="BaseResultMap" type="User" >
        <id column="id" property="id" jdbcType="VARCHAR" />
        <result column="name" property="name" jdbcType="VARCHAR" />
        <result column="role_id" property="roleId" jdbcType="VARCHAR" />
      </resultMap>
    
     <resultMap id="ViewMap" type="UserView" extends="BaseResultMap">
        <result column="role_name" property="roleName" jdbcType="VARCHAR" />
     </resultMap>
        
     <select id="queryList" resultMap="ViewMap" parameterType="UserView">
        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 
    </select>