使用mybatis3--注解方式
1.pom.xml文件搭建mybatis3环境
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.xuebaosoft.mybatis3</groupId> <artifactId>mybatis-annotation</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>mybatis-annotation</name> <url>http://maven.apache.org</url> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>3.8.1</version> <scope>test</scope> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.1.1</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.6</version> </dependency> </dependencies> </project>
2.这里是用MyEclipse10建的一个Java-Maven工程，结构如下，
3.先看一下配置文件mybatis-config.xml（仅仅配置了datasource）
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//ibatis.apache.org//DTD Config 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-config.dtd"> <configuration> <environments default="environment"> <environment id="environment"> <transactionManager type="JDBC" /> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://192.168.191.1:3306/xuebaodb?characterEncoding=UTF-8" /> <property name="username" value="root" /> <property name="password" value="root" /> </dataSource> </environment> </environments> <!-- <mappers> <mapper resource="User.xml" /> </mappers> --> </configuration>
4.为了节省篇幅，仅给出*ServiceImpl源码，源码中仅涉及基本的增删改查操作
package com.xuebaosoft.mybatis3.mybatis_annotation.service.impl;
import java.util.ArrayList;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import com.xuebaosoft.mybatis3.mybatis_annotation.dao.UserDao;
import com.xuebaosoft.mybatis3.mybatis_annotation.model.User;
import com.xuebaosoft.mybatis3.mybatis_annotation.service.UserService;
import com.xuebaosoft.mybatis3.mybatis_annotation.util.SqlSessionFactoryUtil;
public class UserServiceImpl implements UserService {
public void add(String id, String username, String password) {
SqlSession session = SqlSessionFactoryUtil.getInstance().openSession();
try {
session.getMapper(UserDao.class).add(id, username, password);
session.commit();// 提交事务
} catch (Exception e) {
e.printStackTrace();
} finally {
session.close();
}
}
public void delete(String id) {
SqlSession session = SqlSessionFactoryUtil.getInstance().openSession();
try {
session.getMapper(UserDao.class).delete(id);
session.commit();// 提交事务
} catch (Exception e) {
e.printStackTrace();
} finally {
session.close();
}
}
public int update(String username, String password, String id) {
int count = 0;
SqlSession session = SqlSessionFactoryUtil.getInstance().openSession();
try {
count = session.getMapper(UserDao.class).update(username, password, id);
session.commit();// 提交事务
} catch (Exception e) {
count = 0;
e.printStackTrace();
} finally {
session.close();
}
return count;
}
public List<User> getUsers(int offset, int pageSize) {
List<User> users = new ArrayList<User>();
SqlSession session = SqlSessionFactoryUtil.getInstance().openSession();
try {
users = session.getMapper(UserDao.class).getUsersByPage(offset, pageSize);
} catch (Exception e) {
e.printStackTrace();
} finally {
session.close();
}
return users;
}
}
5.给出本人封装的一个util工具用于获取SqlSessionFactory，即SqlSessionFactoryUtil.java，
package com.xuebaosoft.mybatis3.mybatis_annotation.util;
import java.io.IOException;
import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import com.xuebaosoft.mybatis3.mybatis_annotation.dao.UserDao;
public class SqlSessionFactoryUtil {
private static SqlSessionFactory sqlSessionFactory = null;
public static SqlSessionFactory getInstance() {
if (sqlSessionFactory == null) {
String resource = "mybatis-config.xml";
InputStream inputStream = null;
try {
inputStream = Resources.getResourceAsStream(resource);
} catch (IOException e) {
e.printStackTrace();
}
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
// 注解方式查询时需要注册MAPPER
sqlSessionFactory.getConfiguration().addMapper(UserDao.class);
}
return sqlSessionFactory;
}
}
6.给出model--User.java,
package com.xuebaosoft.mybatis3.mybatis_annotation.model;
public class User {
private String id;
private String username;
private String password;
//省略getter和setter。。。
}
7.给出注解的最终实现形式--UserDao.java，这也就是所谓的mybatis的注解使用方式，注解的语法比较通俗易懂，但是还是得自己花时间去熟悉才能运用自如，本篇不作介绍
package com.xuebaosoft.mybatis3.mybatis_annotation.dao;
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import com.xuebaosoft.mybatis3.mybatis_annotation.model.User;
public interface UserDao {
@Insert(" insert into users (id,username,password) values (#{id},#{username},#{password})")
public void add(@Param("id") String id, @Param("username") String username,
@Param("password") String password);
@Delete(" delete from users where id=#{id}")
public void delete(String id);
@Update(" update users set username=#{username},password=#{password} where id=#{id}")
public int update(@Param("username") String username,
@Param("password") String password, @Param("id") String id);
@Select(" select * from users where id=#{id}")
public User getUser(String id);
@Select(" select * from users order by id asc ")
public List<User> getUsers();
@Select(" select * from users order by id asc limit #{pageSize} offset #{offset} ")
public List<User> getUsersByPage(@Param("offset") int offset,
@Param("pageSize") int pageSize);// offset=pageSize*(page-1)
}
解释下@Param ，例如
@Param("username") String username
是让String username对应sql中#{username}，如果Java代码里的参数名字跟sql里的参数名字一致则不需要写@Param注解
8.用junit测试一下，
package com.xuebaosoft.mybatis3.mybatis_annotation;
import java.util.List;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import com.xuebaosoft.mybatis3.mybatis_annotation.model.User;
import com.xuebaosoft.mybatis3.mybatis_annotation.service.UserService;
import com.xuebaosoft.mybatis3.mybatis_annotation.service.impl.UserServiceImpl;
public class AppTest extends TestCase {
public AppTest(String testName) {
super(testName);
}
public static Test suite() {
return new TestSuite(AppTest.class);
}
public void testApp() {
UserService userService = new UserServiceImpl();
userService.add("1002", "张三", "112");
List<User> list = userService.getUsers(0, 1);//分页查询
System.out.println(list);
}
}
9.备注，如果增加一个业务，如图，
即增加了T_UserMapper.java这个业务，那么需要增加的配置如下，
