MyBatis如何入门以及实现一个简单的增删改查
1、首先新建一个MyBatis Maven项目
2、新建一个Employee类。
package com.gwolf.bean;
public class Employee implements java.io.Serializable{
private Integer empId;
private String empName;
private String email;
private String gender;
public Integer getEmpId() {
return empId;
}
public void setEmpId(Integer empId) {
this.empId = empId;
}
public String getEmpName() {
return empName;
}
public void setEmpName(String empName) {
this.empName = empName;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
@Override
public String toString() {
return "Employee [empId=" + empId + ", empName=" + empName + ", email="
+ email + ", gender=" + gender + "]";
}
}
3、在maven配置文件中添加mybatis和mysql数据库驱动的依赖包。并且为了能够看到sql的打印日志，我们还需要加入log4j依赖包。
<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.gwolf</groupId>
<artifactId>Mybatis3</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Mybatis3</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>4.12</version>
<scope>test</scope>
</dependency>
<!-- MyBatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.41</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
</project>
4、创建Employee映射的xml配置文件：EmployeeMapper.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.gwolf.dao.EmployeeMapper">
<!--
namespace:名称空间
id:唯一标识
resultType:返回值类型
#{empId}:从传递过来的参数取出empId值
-->
<select id="selectEmployee" resultType="com.gwolf.bean.Employee">
select * from tbl_emp where emp_id = #{empId}
</select>
</mapper>
5、创建一个mybatis-config.xml文件，用于创建SqlSessionFactory:
<?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"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/ssm_crud"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="EmployeeMapper.xml"/>
</mappers>
</configuration>
6、新建一个java测试类AppTest，用户测试mybatis的增删改查：创建一个SqlSessionFactory对象。
package com.gwolf;
import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;
public class AppTest {
@Test
public void test() throws Exception {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
}
7、下一步是从 SqlSessionFactory 中获取 SqlSession,能直接执行已经映射的sql语句。
package com.gwolf;
import java.io.InputStream;
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.Test;
import com.gwolf.bean.Employee;
public class AppTest {
@Test
public void test() throws Exception {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
try {
Employee employee = sqlSession.selectOne("com.gwolf.dao.EmployeeMapper.selectEmployee", 1);
System.out.println(employee);
}finally {
sqlSession.close();
}
}
}
8、执行单元测试，查看程序运行结果：
