Mybatis入门案例

于 2019-12-20 16:53:41 发布
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分类专栏： Mybatis 文章标签： mybatis maven项目 mybatis简单用例
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本文链接：https://blog.youkuaiyun.com/qq_41629684/article/details/103634257
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一、认识MyBatis

MyBatis 是一款优秀的持久层框架，是一个访问数据库的Java组件。它支持定制化 SQL、存储过程以及高级映射。

二、在哪儿使用Mybatis？

三、使用Ｍybatis

1.在数据库中建一个库为mybatis_db，再建立一个emp表。

create database mybatis_db;
create table emp(
    e_id varchar(20) primary key,
    e_name varchar(50) not null,
    e_sal decimal(8,2) not null,
    e_date date not null
);
insert into emp values('001','emp1','8000',date_sub(now(),interval 50 day) );
insert into emp values('002','emp2','7000',date_sub(now(),interval 30 day) );
insert into emp values('003','emp3','8600',date_sub(now(),interval 150 day) );
insert into emp values('004','emp4','5700',date_sub(now(),interval 350 day) );
insert into emp values('005','emp5','6600',date_sub(now(),interval 850 day) );
insert into emp values('006','emp6','9876',date_sub(now(),interval 500 day) );
insert into emp values('007','emp7','8988',date_sub(now(),interval 660 day) );
insert into emp values('008','emp8','5632',date_sub(now(),interval 550 day) );
insert into emp values('009','emp9','3688',date_sub(now(),interval 510 day) );

2.建一个maven项目,名为mybatis01,在pom文件中导入响应的jar包。mysql驱动包，mybatis包，junit测试,log4j日志。

pom文件如下：

<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>ztt.mybatis</groupId>
	<artifactId>mybatis01</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<dependencies>
	<!-- mysql驱动 -->
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>8.0.18</version>
		</dependency>
		<!-- mybatis包 -->
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.5.3</version>
		</dependency>
		<!-- junit测试 -->
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>
		<!-- log4j日志输出 -->
		<dependency>
			<groupId>org.apache.logging.log4j</groupId>
			<artifactId>log4j-core</artifactId>
			<version>2.13.0</version>
		</dependency>

	</dependencies>
	<build>
		<plugins>
			<plugin>
				<!-- 编译器配置 -->
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-compiler-plugin</artifactId>
				<version>3.8.1</version>
				<configuration>
					<source>1.8</source>
					<target>1.8</target>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

３．创建mybatis.xml和log4j.xml文件,在src/main/resources文件下,文件内容分别为：

mybatis.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>
<!-- 默认数据环境 -->
  <environments default="development">
  <!-- 其中的一个数据环境 -->
    <environment id="development">
<!-- 通过jdbc管理事务 -->
      <transactionManager type="JDBC"/>
      <!-- 数据环境采用数据池 -->
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/mybatis_db"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
  <!-- 映射器所在包名 -->
    <package name="ztt.mybatis.Mapper"/>
  </mappers>
</configuration>

log4j2.xml:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
    </Console>
  </Appenders>
  <Loggers>
  <!-- 映射器的包名 -->
    <Logger name="ztt.mybatis.Mapper" level="trace" additivity="false">
      <AppenderRef ref="Console"/>
    </Logger>
    <Root level="error">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

４．创建JavaBean,在ztt.mybatis.model包下,文件如下：

package ztt.mybatis.model;

import java.util.Date;

public class Employee {
	private String e_id;
	private String e_name;
	private Double e_sal;
	private Date e_date;
	public Employee() {
		super();
		// TODO Auto-generated constructor stub
	}
	public Employee(String e_id, String e_name, Double e_sal, Date e_date) {
		super();
		this.e_id = e_id;
		this.e_name = e_name;
		this.e_sal = e_sal;
		this.e_date = e_date;
	}
	public String getE_id() {
		return e_id;
	}
	public void setE_id(String e_id) {
		this.e_id = e_id;
	}
	public String getE_name() {
		return e_name;
	}
	public void setE_name(String e_name) {
		this.e_name = e_name;
	}
	public Double getE_sal() {
		return e_sal;
	}
	public void setE_sal(Double e_sal) {
		this.e_sal = e_sal;
	}
	public Date getE_date() {
		return e_date;
	}
	public void setE_date(Date e_date) {
		this.e_date = e_date;
	}
}

package ztt.mybatis.model;

public class EmployeeDto {

	private Double start_sal;
	private Double end_sal;
	public EmployeeDto(Double start_sal, Double end_sal) {
		super();
		this.start_sal = start_sal;
		this.end_sal = end_sal;
	}
	public Double getStart_sal() {
		return start_sal;
	}
	public void setStart_sal(Double start_sal) {
		this.start_sal = start_sal;
	}
	public Double getEnd_sal() {
		return end_sal;
	}
	public void setEnd_sal(Double end_sal) {
		this.end_sal = end_sal;
	}
	

}

5.创建Mapper接口，在ztt.mybatis.mapper包下

package ztt.mybatis.Mapper;

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 ztt.mybatis.model.Employee;
import ztt.mybatis.model.EmployeeDto;

public interface EmployeeMapper {
	// 1.查询表中所有的数据
	@Select("select * from emp")
	public List<Employee> findEmployeeList();

	// 2.根据名称查询
	@Select("select * from emp where e_name like concat('%',#{name},'%')")
	public List<Employee> findEmployeeList1(String name);

	// 3.根据工资范围来查(两个参数)
	@Select("select * from emp where e_sal >=#{start_sal} and e_sal <=#{end_sal}")
	public List<Employee> findEmployeeList２(@Param("start_sal") Double start_sal, @Param("end_sal") Double end_sal);

	// 4.根据工资范围来查(两个参数),通过javaBean,占位符
	@Select("select * from emp where e_sal >=#{start_sal} and e_sal <=#{end_sal}")
	public List<Employee> findEmployeeList3(EmployeeDto dto);

	// 5.根据工资范围来查(两个参数),通过javaBean，$
	@Select("select * from emp where e_sal >=${start_sal} and e_sal <=${end_sal}")
	public List<Employee> findEmployeeList4(EmployeeDto dto);
	
	// 6.插入数据
		@Insert("insert into emp(e_id,e_name,e_sal,e_date) values (#{e_id},#{e_name},#{e_sal},#{e_date})")
		public int insertEmployeeList5(Employee emp);
		
		//7.删除数据（全删）
		@Delete("delete from emp")
		public int deleteAllEmployeeList6();
		
		//8.删除数据（根据名称删除）
		@Delete("delete from emp where e_name like concat('%',#{name},'%')")
		public List<Employee> deleteEmployeeList7(String name);
		
		// 9.根据工资范围来删除(两个参数)
		@Delete("delete from emp where e_sal >=#{start_sal} and e_sal <=#{end_sal}")
		public List<Employee> deleteEmployeeList8(@Param("start_sal") Double start_sal, @Param("end_sal") Double end_sal);

		//10.更新工资,全部加３３３３
		@Update("update emp set e_sal=e_sal+3333 ")
		public List<Employee> updateEmployeeList9();
		
}

６．创建Junit测试,在ztt.mybatis.test包下。

package ztt.mybatis.test;

import static org.junit.Assert.*;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.ExecutorType;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

import ztt.mybatis.Mapper.EmployeeMapper;
import ztt.mybatis.model.Employee;
import ztt.mybatis.model.EmployeeDto;

public class EmployeeTest {
	private static SqlSessionFactory sqlSessionFactory;

	@BeforeClass // 所有测试开始之前需要需要一次性执行的代码
	public static void setUpBeforeClass() throws Exception {
		// 加载配置文件
		InputStream is = Resources.getResourceAsStream("mybatis.xml");
		// 创建ＳqlSessionFactory
		sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
	}

	@AfterClass // 所有测试结束之后需要需要一次性执行的代码
	public static void tearDownAfterClass() throws Exception {
	}

	private SqlSession session;
	private EmployeeMapper mapper;

	@Before
	public void setUp() throws Exception {
		session = sqlSessionFactory.openSession(ExecutorType.REUSE);
		mapper = session.getMapper(EmployeeMapper.class);
	}

	@After // 每一个测试方法执行之后都需要执行的代码
	public void tearDown() throws Exception {
		session.commit();
		session.close();
	}

	@Test // 全查
	public void test() {
		List<Employee> list = mapper.findEmployeeList();
		// for(Employee e:list) {
		// System.out.println(e.getE_id()+","+e.getE_name()+","+e.getE_sal()+","+e.getE_date());
		// }
	}

	@Test // 根据名称查询
	public void test1() {
		mapper.findEmployeeList1("8");
	}

	@Test // 根据工资范围来查查询
	public void test２() {
		mapper.findEmployeeList２(3000.0, 5000.0);
	}

	@Test // 根据工资范围来查查询,javabean的形式
	public void test3() {
		mapper.findEmployeeList3(new EmployeeDto(3000.0, 5000.0));
	}

	@Test // 根据工资范围来查查询,javabean的形式
	public void test４() {
		mapper.findEmployeeList4(new EmployeeDto(3000.0, 5000.0));
	}

	@Test // ５．插入数据
	public void test5() {
		for (int i = 201; i < 302; i++) {
			mapper.insertEmployeeList5(
					new Employee(String.valueOf(i), "新员工" + i, Math.random() * 5000 + 2000, new Date()));
		}
	}
	@Test // ６．删除数据
	public void test６() {
		mapper.deleteAllEmployeeList6();
	}
	@Test // ７．根据名称删除
	public void test7() {
		mapper.deleteEmployeeList7("8");
	}
	@Test // 8.根据工资范围来删除
	public void test8() {
		mapper.deleteEmployeeList8(3000.0, 5000.0);
	}
	@Test // 10.更新工资,全部加３３３３
	public void test9() {
		mapper.updateEmployeeList9();
	}
}

7.运行junit文件或其中的一个方法。

８．运行结果

 

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