Java EE数据持久化框架mybatis练习——获取id值为1的角色信息。

你的名字 2023-01-13 04:21 112阅读 0赞

### 实现要求： ###

获取id值为1的角色信息。

### 实现思路： ###

创建角色表sys\_role所对应的实体类sysRole。

package entity;
    
    public class SysRole {
    	private long id;
    	private String roleName;
    	private int enabled;
    	private String createBy;
    	private String createTime;
    	public SysRole() {
    		super();
    	}
    	public SysRole(long id, String roleName, int enabled, String createBy, String createTime) {
    		super();
    		this.id = id;
    		this.roleName = roleName;
    		this.enabled = enabled;
    		this.createBy = createBy;
    		this.createTime = createTime;
    	}
    	@Override
    	public String toString() {
    		return "SysRole [id=" + id + ", roleName=" + roleName + ", enabled=" + enabled + ", createBy=" + createBy
    				+ ", createTime=" + createTime + "]";
    	}
    	public long getId() {
    		return id;
    	}
    	public void setId(long id) {
    		this.id = id;
    	}
    	public String getRoleName() {
    		return roleName;
    	}
    	public void setRoleName(String roleName) {
    		this.roleName = roleName;
    	}
    	public int getEnabled() {
    		return enabled;
    	}
    	public void setEnabled(int enabled) {
    		this.enabled = enabled;
    	}
    	public String getCreateBy() {
    		return createBy;
    	}
    	public void setCreateBy(String createBy) {
    		this.createBy = createBy;
    	}
    	public String getCreateTime() {
    		return createTime;
    	}
    	public void setCreateTime(String createTime) {
    		this.createTime = createTime;
    	}
    	
    }

创建操作sysRole的映射器接口RoleMapper，并在其中定义SysRole selectById(Long id)方法。

package mapper;
    
    import entity.SysRole;
    
    public interface RoleMapper {
    	SysRole selectById(long id);
    }

定义RoleMapper.xml，在其中定义<select>标签，注意返回结果的resultMap映射说明。

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    	"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
    
    <mapper namespace="mapper.RoleMapper">
    	<resultMap type="SysRole" id="RoleMap">
    		<id property="id" column="id"/>
    		<result property="roleName" column="role_name"/>
    		<result property="enabled" column="enabled"/>
    		<result property="cretaBy" column="creta_by"/>
    		<result property="createTime" column="create_time" jdbcType="TIMESTAMP"/>
    	</resultMap>
    	<select id="selectById" resultMap="RoleMap">
    		select * from sys_role where id=#{id}
    	</select>
    </mapper>

编写测试类测试方法调用。

package test;
    
    import java.io.IOException;
    import java.io.Reader;
    import java.util.List;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    import org.junit.BeforeClass;
    import org.junit.Test;
    
    import mapper.RoleMapper;
    
    public class RoleMapperTest {
    	private static SqlSessionFactory sqlSessionFactory;
    
    	/* 完成mybatis配置的加载，创建得到SqlSessionFactory */
    	@BeforeClass
    	public static void init() {
    		try {
    			Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
    			sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
    			reader.close();
    		} catch (IOException e) {
    			e.printStackTrace();
    		}
    	}
    
    	/* 获取SqlSession对象，用于调用方法得到数据 */
    	@Test
    	public void testSelectAll() {
    		SqlSession sqlSession = sqlSessionFactory.openSession();
    		try {
    			RoleMapper roleMapper = sqlSession.getMapper(RoleMapper.class);
    			roleMapper.selectById(1L);
    		} finally {
    			// 不要忘记关闭sqlSession
    			sqlSession.close();
    		}
    	}
    }

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