本次环境MySQL5.7.20+MyBatis3.4.1+JDK9.0，用到的插件有：
1.创建一个数据库mybatis和表格tbl_employee：
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CREATE DATABASE mybatis DEFAULT CHARSET utf8;
USE mybatis;
CREATE TABLE tbl_employee1(
id INT(11) PRIMARY KEY AUTO_INCREMENT,
last_name VARCHAR(255),
gender CHAR(1),
email VARCHAR(255)
);2.创建一个MyBatis java工程，编写与数据库中对应字段的Employee类：
package com.atguigu.mybatis.bean;
import org.apache.ibatis.type.Alias;
@Alias("emp")
public class Employee {
private Integer id;
private String lastName;
private String email;
private String gender;
public Employee() {
super();
}
public Employee(Integer id, String lastName, String email, String gender) {
super();
this.id = id;
this.lastName = lastName;
this.email = email;
this.gender = gender;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
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 [id=" + id + ", lastName=" + lastName + ", email=" + email + ", gender=" + gender + "]";
}
}3.创建EmployeeMapper接口,添加增删改查方法，此接口中的方法可以与映射到xml文件
package com.atguigu.mybatis.dao;
import com.atguigu.mybatis.bean.Employee;
public interface EmployeeMapper {
//查询
public Employee getEmpById(Integer id);
//插入
public Long addEmp(Employee employee);
//修改
public boolean updateEmp(Employee employee);
//删除
public void deleteEmpById(Integer id);
}
4.创建dbconfig.properties文件,存放的是JDBC信息
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://10.0.0.40:3306/mybatis
jdbc.username=chendan
jdbc.password=1234565.创建mybatis-config.xml主配置文件，定义了数据库相关信息
6.创建EmployeeMapper.xml映射文件，存放的主要是SQL语句：
insert into tbl_employee1(last_name,email,gender)
values(#{lastName},#{email},#{gender})
update tbl_employee1
set last_name=#{lastName},email=#{email},gender=#{gender}
where id=#{id}
delete from tbl_employee1 where id=#{id}
7.创建测试类，主要用于JUnit测试使用
package com.atguigu.mybatis.test;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Method;
import java.lang.reflect.Field;
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.atguigu.mybatis.bean.Employee;
import com.atguigu.mybatis.dao.EmployeeMapper;
public class MyBatisTest {
public SqlSessionFactory getSqlSessionFactory() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
return new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void test01() throws IOException {
// 1、获取sqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
// 2、获取sqlSession对象
SqlSession openSession = sqlSessionFactory.openSession();
try {
// 3、获取接口的实现类对象
// 会为接口自动的创建一个代理对象，代理对象去执行增删改查方法
EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
Employee employee = mapper.getEmpById(1);
System.out.println(mapper.getClass());
System.out.println(employee);
} finally {
openSession.close();
}
}
@Test
public void test02() throws IOException {
SqlSessionFactory sqlSessionFactory = getSqlSessionFactory();
SqlSession openSession = sqlSessionFactory.openSession();
try {
EmployeeMapper mapper = openSession.getMapper(EmployeeMapper.class);
Employee employee = new Employee(null,"Jack","Jack@atguigu.com","0");
mapper.addEmp(employee);
// Employee employee = new Employee(5,"Jack","Jack@atguigu.com","1");
// boolean isupdate = mapper.updateEmp(employee);
// System.out.println(isupdate);
// mapper.deleteEmpById(4);
openSession.commit();
} finally {
openSession.close();
}
}
}运行结果如下：
1、执行查询操作,可以看到数据库中只有一条数据：
Employee employee = mapper.getEmpById(1);
System.out.println(employee);
Employee [id=1, lastName=Jack, email=Jack@atguigu.com, gender=0]
查询成功2、执行增加一条数据，执行查询结果如下：
Employee employee = new Employee(null,"Peter","Peter@atguigu.com","1");
mapper.addEmp(employee);
openSession.commit();
Employee employee = mapper.getEmpById(2);
System.out.println(employee);
DEBUG 08-01 15:11:13,512 <== Updates: 1 (BaseJdbcLogger.java:145)
Employee [id=2, lastName=Peter, email=Peter@atguigu.com, gender=1]
添加成功3.修改数据库中的数据，执行结果如下：
Employee employee = new Employee(2,"Jack","Jack@atguigu.com","1");
boolean isupdate = mapper.updateEmp(employee);
openSession.commit();
Employee employee = mapper.getEmpById(2);
System.out.println(employee);
DEBUG 08-01 15:18:02,625 <== Updates: 1 (BaseJdbcLogger.java:145)
Employee [id=2, lastName=Jack, email=Jack@atguigu.com, gender=1]
修改成功4.删除数据库中的数据，执行结果如下：
mapper.deleteEmpById(2);
openSession.commit();
Employee employee = mapper.getEmpById(2);
System.out.println(employee);
DEBUG 08-01 15:23:09,434 <== Updates: 1 (BaseJdbcLogger.java:145)
null
查询数据删除成功总结：MyBatis操作数据库简单快捷，将代码与sql语句分离出来，非常好！
