标签:entity sessionFactory person session statement reader MyBatis
1.config.xml文件的基本配置信息
2.选择数据源
3.mybatis约定
(1)parameterType和resultType 只能传一个参数,但是我们可以传一个数组或者集合,达到传多个参数的目的
(2)输入参数:如果是(8种常用数据类型+String),是可以使用任何占位符#{xxxx};如果是对象类型,则必须是对象的属性名#{属性名}
(3)输出类型:返回到Java实体类
4.增、删、改、查
(1)mapper.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="entity.personMapper"> <!-- 查询 --> <select id="select" resultType="entity.Person" parameterType="int"> select * from Person </select> <!--增加 --> <insert id="insert" parameterType="entity.Person"> insert into Person values(#{id},#{name},#{age}) </insert> <!--删除 --> <delete id="delete" parameterType="int"> delete from Person where id=#{id} </delete> <!--改 --> <update id="update" parameterType="entity.Person"> update Person set name=#{name},age=#{age} where id=#{id} </update> </mapper>
(2)Java主函数
package entity; 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; public class starts { public static void main(String[] args) throws IOException { //insert(); //delete(); update(); select(); } public static void select() throws IOException { Reader reader = Resources.getResourceAsReader("entity/config.xml"); SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader,"development1"); SqlSession session = sessionFactory.openSession(); String statement = "entity.personMapper."+"select"; List<Person> person = session.selectList(statement); System.out.println(person); session.close(); } public static void insert() throws IOException { Reader reader = Resources.getResourceAsReader("entity/config.xml"); SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader,"development1"); SqlSession session = sessionFactory.openSession(); Person person = new Person(4,"赵帅",36); String statement = "entity.personMapper."+"insert"; int count = session.insert(statement,person); session.commit(); System.out.println("增加"+count+"记录"); session.close(); } public static void delete() throws IOException { Reader reader = Resources.getResourceAsReader("entity/config.xml"); SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader,"development1"); SqlSession session = sessionFactory.openSession(); String statement = "entity.personMapper."+"delete"; int count = session.insert(statement,2); session.commit(); System.out.println("删除"+count+"记录"); session.close(); } public static void update() throws IOException { Reader reader = Resources.getResourceAsReader("entity/config.xml"); SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader,"development1"); SqlSession session = sessionFactory.openSession(); String statement = "entity.personMapper."+"update"; Person person = new Person(); person.setId(2); person.setName("李志明"); person.setAge(36); int count = session.update(statement,person);//注意:这里应该传实体类,不是person.getId(),不然会报错 session.commit(); System.out.println("更新"+count+"记录"); session.close(); } }
5.总结
(1)java的实体类,在创建有参构造器后,必须同时创建无参构造器,否则在Java程序中将无法进行实例化。
标签:entity,sessionFactory,person,session,statement,reader,MyBatis 来源: https://www.cnblogs.com/ibear/p/10777876.html
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