Mybatis注解方法操作数据库
Java中使用Mybatis操作数据库主要有两种方法：注解和xml配置，注解相对比较简单和方便，两种方式的效果一致。本文以注解的方式说明用Mybatis访问数据库的方法
一、创建数据表(MySql)
1 2 3 4 5 6 7 8 9 | -- ------------------------------ Table structure for admininfo-- ----------------------------DROP TABLE IF EXISTS `admininfo`;CREATE TABLE `admininfo` ( `ID` int(11) NOT NULL AUTO_INCREMENT, `AdminName` varchar(20) NOT NULL, PRIMARY KEY (`ID`)) ENGINE=InnoDB AUTO_INCREMENT=25 DEFAULT CHARSET=latin1; |
二、创建mybatis的配置文件：mybatisConf.xml，由于使用maven进行管理，所以放在java-->resources文件夹下，其它位置也可以，只有最终在\target\classes\mybatisConf.xml生成文件即可
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 | <?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> <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="username" value="root" /> <property name="password" value="root" /> </dataSource> </environment> </environments> <mappers> <!-- 注册映射接口，该接口文件包含了数据访问方法和SQL --> <mapper class="dal.dataaccess.IAdminInfoMapper" /> </mappers></configuration> |
三、创建IAdminInfoMapper文件（本文中包名为dal.dataaccess)
该接口的功能主要是提供对AdminInfo表的数据操作
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 | package dal.dataaccess;import java.util.List;import org.apache.ibatis.annotations.Delete;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.annotations.Update;import dal.beans.AdminInfo;import dal.beans.AdminRightInfo;public interface IAdminInfoMapper { //使用@Select注解指明getById方法要执行的SQL @Select("select * from admininfo where id=#{id}") public AdminInfo getById(int id); //使用@Select注解指明getAll方法要执行的SQL @Select("select * from admininfo") public List<AdminInfo> getAll(); //使用@Insert注解指明add方法要执行的SQL @Insert("insert into admininfo(adminName) values(#{adminName})") public int add(AdminInfo user); //使用@Update注解指明update方法要执行的SQL @Update("update admininfo set adminName=#{adminName} where id=#{id}") public int update(AdminInfo user); //使用@Delete注解指明deleteById方法要执行的SQL @Delete("delete from admininfo where id=#{id}") public int deleteById(int id);} |
四、定义操作数据库的公共方法
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | package framework.utils;import java.io.InputStream;import org.apache.ibatis.session.SqlSession;import org.apache.ibatis.session.SqlSessionFactory;import org.apache.ibatis.session.SqlSessionFactoryBuilder;public class MyBatisUtil { /** * 获取SqlSessionFactory * * @return SqlSessionFactory */ public static SqlSessionFactory getSqlSessionFactory() { String resource = "mybatisConf.xml"; InputStream is = MyBatisUtil.class.getClassLoader().getResourceAsStream(resource); SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is); return factory; } /** * 获取SqlSession * * @return SqlSession */ public static SqlSession getSqlSession() { return getSqlSessionFactory().openSession(); } /** * 获取SqlSession * * @param isAutoCommit * true 表示创建的SqlSession对象在执行完SQL之后会自动提交事务 false * 表示创建的SqlSession对象在执行完SQL之后不会自动提交事务，这时就需要我们手动调用sqlSession. * commit()提交事务 * @return SqlSession */ public static SqlSession getSqlSession(boolean isAutoCommit) { return getSqlSessionFactory().openSession(isAutoCommit); }} |
五、对adminInfo表进行增删改查
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 | package test;import java.util.List;import org.apache.ibatis.session.SqlSession;import org.junit.Test;import dal.beans.*;import framework.utils.MyBatisUtil;import dal.dataaccess.*;public class MybatisAnnotationTest { @Test public void Select() { SqlSession sqlSession = MyBatisUtil.getSqlSession(); // 得到AdminInfoMapper接口的实现类对象，IAdminInfoMapper接口的实现类对象由sqlSession.getMapper(IAdminInfoMapper.class)动态构建出来 IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class); // 执行查询操作，将查询结果自动封装成User返回 AdminInfo bean = mapper.getById(13); // 使用SqlSession执行完SQL之后需要关闭SqlSession sqlSession.close(); System.out.println(bean.getId()); System.out.println(bean.getAdminName()); } @Test public void SelectAll() { SqlSession sqlSession = MyBatisUtil.getSqlSession(); IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class); List<AdminInfo> bean = mapper.getAll(); sqlSession.close(); System.out.println(bean.size()); } @Test public void Insert() { SqlSession sqlSession = MyBatisUtil.getSqlSession(); IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class); AdminInfo bean = new AdminInfo(); bean.setAdminName("Admin" + System.currentTimeMillis()); int result = mapper.add(bean); sqlSession.commit(); sqlSession.close(); System.out.println(result); } @Test public void Update() { SqlSession sqlSession = MyBatisUtil.getSqlSession(); IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class); AdminInfo bean = new AdminInfo(); bean.setId(12); bean.setAdminName("Admin" + System.currentTimeMillis()); int result = mapper.update(bean); sqlSession.commit(); sqlSession.close(); System.out.println(result); } @Test public void Delete() { SqlSession sqlSession = MyBatisUtil.getSqlSession(); IAdminInfoMapper mapper = sqlSession.getMapper(IAdminInfoMapper.class); int result = mapper.deleteById(12); sqlSession.commit(); sqlSession.close(); System.out.println(result); }} |
六、由于使用了maven进行依赖管理，pom.xml还需要添加
1 2 3 4 5 6 7 8 9 10 | <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.38</version> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.3.0</version> </dependency> |
