一.工程结构
二.在类路径下创建mybatis的配置文件Configuration.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><!-- 别名 --> <typeAlias alias="User" type="com.bijian.study.model.User" /> </typeAliases> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"><!-- 数据源 --> <property name="driver" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://10.60.222.65:3306/test" /> <property name="username" value="test" /> <property name="password" value="test" /> </dataSource> </environment> </environments> <mappers><!-- ORM映射文件 --> <mapper resource="com/bijian/study/model/User.xml" /> </mappers> </configuration>
三.执行创建数据库和表的sql
-- Create the database named 'hbatis'.
-- It's OK to use `, not OK to use ' or " surrounding the database name to prevent it from being interpreted as a keyword if possible.
CREATE DATABASE IF NOT EXISTS `hbatis`
DEFAULT CHARACTER SET = `UTF8`;
-- Create a table named 'User'
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(50) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
`address` varchar(200) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
-- Insert a test record
Insert INTO `user` VALUES ('1', 'bijian', '120', 'hangzhou,westlake');
-- drop table
drop table `user`;
四.User类
package com.bijian.study.model;
public class User {
private int id;
private String name;
private int age;
private String address;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
// 如果有带参数的构造器,编译器不会自动生成无参构造器。当查询需要返回对象时,ORM框架用反射来调用对象的无参构造函数,导致异常:java.lang.NoSuchMethodException: com.bijian.study.model.User.<init>()
// 这时需要明确写出:
public User() {
}
public User(int id, String address) {
this.id = id;
this.address = address;
}
public User(String name, int age, String address) {
this.name = name;
this.age = age;
this.address = address;
}
}
User.java对应的User.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.bijian.study.model.UserMapper"> <select id="getUserById" parameterType="int" resultType="User"> select * from `user` where id = #{id} </select> </mapper>
五.测试类
package com.bijian.study.test;
import java.io.IOException;
import java.io.Reader;
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 org.junit.BeforeClass;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.bijian.study.model.User;
public class MyBatisBasicTest {
private static final Logger log = LoggerFactory.getLogger(MyBatisBasicTest.class);
private static SqlSessionFactory sqlSessionFactory;
private static Reader reader;
@BeforeClass
public static void initial() {
try {
reader = Resources.getResourceAsReader("Configuration.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
log.error("Error thrown while reading the configuration: {}", e);
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
log.error("Error thrown while closing the reader: {}", e);
}
}
}
}
@Test
public void queryTest() {
SqlSession session = sqlSessionFactory.openSession();
User user = (User) session.selectOne("com.bijian.study.model.UserMapper.getUserById", 1);
log.info("{}: {}", user.getName(), user.getAddress());
}
}
运行单元测试结果:
00:28:18.710 [main] INFO com.bijian.study.test.MyBatisBasicTest - bijian: hangzhou,westlake