MyBatis是一个支持 普通 SQL 查询 , 存储过程 和 高级映射 的优秀 持久层框架 。MyBatis消除了几乎所有的JDBC代码和参数的手工设置以及对结果集的检索封装。MyBatis可以使用简单的 XML或注解 用于配置和原始映射,将接口和Java的POJO(Plain Old Java Objects,普通的Java对象)映射成数据库中的记录。
【MyBatis】
<!-- mybatis begin --> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.2.3</version> </dependency> <!-- mybatis end -->
<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.31</version> </dependency>
CREATE DATABASE mybatis_test; USE mybatis_test; CREATE TABLE user ( name varchar(50) CHARACTER SET utf8 DEFAULT NULL, age int(11) DEFAULT NULL, UNIQUE KEY name (name) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
package cn.jxufe.web.mybatis; public class User { private String name; private Integer age; public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public User(String name, Integer age) { super(); this.name = name; this.age = age; } public User() { super(); } }
<?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">
<!-- 为这个mapper指定一个唯一的namespace,namespace的值习惯上设置成包名+sql映射文件名,这样就能够保证namespace的值是唯一的 -->
<mapper namespace="cn.jxufe.web.mybatis.UserMapper"> <!-- 这里namespace必须是UserMapper接口的路径,不然要运行的时候要报错 “is not known to the MapperRegistry” --> <insert id="insertUser" parameterType="User"> insert into user(name,age) values(#{name},#{age}) <!-- 这里sql结尾不能加分号,否则报“ORA-00911”的错误 --> </insert> <!-- 在select标签中编写查询的SQL语句, 设置select标签的id属性为getUser,id属性值必须是唯一的,
不能够重复使用parameterType属性指明查询时使用的参数类型,resultType属性指明查询返回的结果集类型 --> <!-- 这里的id必须和UserMapper接口中的接口方法名相同,不然运行的时候也要报错 --> <select id="getUser" resultType="User" parameterType="java.lang.String"> select * from user where name=#{name} </select> </mapper>
package cn.jxufe.web.mybatis; public interface UserMapper { public void insertUser(User user); public User getUser(String name); }
<?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> <settings> <!-- changes from the defaults for testing --> <setting name="cacheEnabled" value="false" /> <setting name="useGeneratedKeys" value="true" /> <setting name="defaultExecutorType" value="REUSE" /> </settings> <typeAliases> <typeAlias alias="User" type="cn.jxufe.web.mybatis.User"/> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="jdbc"/>
<!-- 配置数据库连接信息 --> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis_test"/> <property name="username" value="root"/> <property name="password" value="123456"/> </dataSource> </environment> </environments> <mappers> <!-- 注册UserMapper.xml文件--> <mapper resource="mappers/UserMapper.xml" /> </mappers> </configuration>
package cn.jxufe.web.mybatis; import java.io.IOException; import java.io.Reader; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MyBatisUtil { private final static SqlSessionFactory sqlSessionFactory; static { String resource = "mybatis-config.xml"; Reader reader = null; try { reader = Resources.getResourceAsReader(resource); } catch (IOException e) { System.out.println(e.getMessage()); } sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); } public static SqlSessionFactory getSqlSessionFactory() { return sqlSessionFactory; } }
package cn.jxufe.web.mybatis; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; public class TestMyBatis { static SqlSessionFactory sqlSessionFactory = null; static { sqlSessionFactory = MyBatisUtil.getSqlSessionFactory(); } // public static void main(String[] args) { // testAdd(); // getUser(); // } public static void testAdd() { SqlSession sqlSession = sqlSessionFactory.openSession(); try { UserMapper userMapper = sqlSession.getMapper(UserMapper.class); User user = new User("lisi", new Integer(25)); userMapper.insertUser(user); sqlSession.commit();// 这里一定要提交,不然数据进不去数据库中 } finally { sqlSession.close(); } } public static void getUser() { SqlSession sqlSession = sqlSessionFactory.openSession(); try { UserMapper userMapper = sqlSession.getMapper(UserMapper.class); User user = userMapper.getUser("lisi"); System.out.println("name: " + user.getName() + "|age: " + user.getAge()); } finally { sqlSession.close(); } } }
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