一、简介
MyBatis 是一款优秀的持久层框架,它支持定制化 SQL、存储过程以及高级映射。
二、入门使用
1、添加依赖
a、使用maven管理依赖,以我本次使用的版本为例
<dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.2.3</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.38</version> </dependency> </dependencies>
b、也可以使用gradle管理依赖
dependencies { testCompile group: ‘junit‘, name: ‘junit‘, version: ‘4.12‘ compile ‘org.mybatis:mybatis:3.2.3‘ compile ‘mysql:mysql-connector-java:5.1.38‘ }
c、也可以去官网下载,官网地址:http://www.mybatis.org/mybatis-3/
2、初始化数据库和初始数据,以数据库moy_mybatis和表t_test为例
## 创建数据库 CREATE DATABASE moy_mybatis; ## 创建一个测试表 CREATE TABLE t_test( id INT(11) AUTO_INCREMENT, create_time DATE COMMENT ‘创建时间‘, modify_time DATE COMMENT ‘修改时间‘, content VARCHAR (50) COMMENT ‘内容‘, PRIMARY KEY (id) );
3、新建实体类TestEntity
package com.moy.mybatis3.entity; import java.util.Date; /** * [Project]:moy-gradle-project <br/> * [Email]:moy25@foxmail.com <br/> * [Date]:2018/2/20 <br/> * [Description]: <br/> * * @author YeXiangYang */ public class TestEntity { private Integer id; private Date createTime; private Date modifyTime; private String content; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public Date getCreateTime() { return createTime; } public void setCreateTime(Date createTime) { this.createTime = createTime; } public Date getModifyTime() { return modifyTime; } public void setModifyTime(Date modifyTime) { this.modifyTime = modifyTime; } public String getContent() { return content; } public void setContent(String content) { this.content = content; } @Override public String toString() { return "TestEntity{" + "id=" + id + ", createTime=" + createTime + ", modifyTime=" + modifyTime + ", content=‘" + content + ‘\‘‘ + ‘}‘; } }
4、新建接口TestMapper
package com.moy.mybatis3.mapper; import com.moy.mybatis3.entity.TestEntity; import java.io.Serializable; import java.util.List; /** * [Project]:moy-gradle-project <br/> * [Email]:moy25@foxmail.com <br/> * [Date]:2018/2/20 <br/> * [Description]: <br/> * * @author YeXiangYang */ public interface TestMapper { List<TestEntity> list(); TestEntity get(Serializable id); int insert(TestEntity TestEntity); int update(TestEntity TestEntity); int delete(Serializable id); int count(); }
5、新建实体映射文件Test.xml
<?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="com.moy.mybatis3.mapper.TestMapper"> <select id="list" resultType="TestEntity"> SELECT * FROM t_test </select> <select id="count" resultType="int"> SELECT count(*) FROM t_test </select> <select id="get" parameterType="int" resultType="TestEntity"> SELECT id,create_time as createTime,modify_time as modifyTime ,content FROM t_test WHERE id=#{id} </select> <insert id="insert" parameterType="TestEntity"> INSERT INTO t_test (create_time,modify_time,content) VALUES (#{createTime},#{modifyTime},#{content}) </insert> <update id="update" parameterType="TestEntity"> UPDATE t_test SET modify_time=#{modifyTime},content=#{content} WHERE id = #{id} </update> <delete id="delete" parameterType="int"> DELETE FROM t_test WHERE id = #{id} </delete> </mapper>
6、新建mybatis配置信息文件mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <typeAliases> <!--项目实体类对应的包名--> <package name="com.moy.mybatis3.entity"/> </typeAliases> <!--myql数据库连接信息--> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/moy_mybatis?useSSL=false"/> <property name="username" value="root"/> <property name="password" value="123"/> </dataSource> </environment> </environments> <!--配置实体映射xml路径--> <mappers> <mapper resource="mapper/Test.xml"></mapper> </mappers> </configuration>
7、为了方便测试,编写一个获取SqlSession的工具类Mybatis3Utils
package com.moy.mybatis3.utils; 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 java.io.IOException; import java.io.Reader; import java.util.Objects; /** * [Project]:moy-gradle-project <br/> * [Email]:moy25@foxmail.com <br/> * [Date]:2018/2/19 <br/> * [Description]: <br/> * * @author YeXiangYang */ public abstract class Mybatis3Utils { public static final SqlSessionFactory sqlSessionFactory; public static final ThreadLocal<SqlSession> sessionThread = new ThreadLocal<>(); static { try { Reader reader = Resources.getResourceAsReader("mybatis-config.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); } catch (IOException e) { throw new RuntimeException(e); } } public static SqlSession getCurrentSqlSession() { SqlSession sqlSession = sessionThread.get(); if (Objects.isNull(sqlSession)) { sqlSession = sqlSessionFactory.openSession(); sessionThread.set(sqlSession); } return sqlSession; } public static void closeCurrentSession() { SqlSession sqlSession = sessionThread.get(); if (Objects.nonNull(sqlSession)) { sqlSession.close(); } sessionThread.set(null); } }
8、新建测试类TestMapperTest测试
package com.moy.mybatis3.mapper; import com.moy.mybatis3.entity.TestEntity; import com.moy.mybatis3.utils.Mybatis3Utils; import org.apache.ibatis.session.SqlSession; import org.junit.After; import org.junit.Before; import org.junit.Test; import java.util.Arrays; import java.util.Date; import java.util.List; import static org.junit.Assert.*; /** * [Project]:moy-gradle-project <br/> * [Email]:moy25@foxmail.com <br/> * [Date]:2018/2/20 <br/> * [Description]: <br/> * * @author YeXiangYang */ public class TestMapperTest { SqlSession sqlSession; TestMapper testMapper; @Before public void before() { sqlSession = Mybatis3Utils.getCurrentSqlSession(); testMapper = sqlSession.getMapper(TestMapper.class); } @After public void after() { Mybatis3Utils.closeCurrentSession(); } @Test public void insert() { TestEntity entity = new TestEntity(); entity.setCreateTime(new Date()); entity.setModifyTime(new Date()); entity.setContent("我是内容"); System.out.println(testMapper.insert(entity)); sqlSession.commit(); } @Test public void count() { System.out.println(testMapper.count()); } @Test public void list() { List<TestEntity> list = testMapper.list(); System.out.println(Arrays.toString(list.toArray())); } @Test public void get() { System.out.println(testMapper.get(1)); } @Test public void update() { TestEntity entity = new TestEntity(); entity.setId(1); entity.setModifyTime(new Date()); entity.setContent("我是修改后内容"); testMapper.update(entity); sqlSession.commit(); } @Test public void delete() { testMapper.delete(1); sqlSession.commit(); } }
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