Mybatis入门案例
搭建Mybatis开发环境–基础CRUD操作实例
select
创建MySQL数据库和表
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| CREATE TABLE `student` (
`id` int(11) NOT NULL ,
`name` varchar(255) DEFAULT NULL,
`email` varchar(255) DEFAULT NULL,
`age` int(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
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创建Maven工程，并且在pom.xml中加入maven坐标
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<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.1</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.9</version>
</dependency>
</dependencies>
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加入maven插件
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| <build>
<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.properties</include>
<include>**/*.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
<build/>
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编写Student实体类
创建包com.bytedance.domain,包中创建Student类
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| package com.bjpowernode.domain;
public class Student {
private Integer id;
private String name;
private String email;
private Integer age;
}
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编写Dao接口 StudentDao
创建包com.bytedance.dao,创建StudentDao接口
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| package com.bjpowernode.dao;
import com.bjpowernode.domain.Student;
import java.util.List;
public interface StudentDao {
List<Student> selectStudents();
}
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编写Dao接口Mapper映射文件StudentDao.xml
要求：
- 在 dao 包中创建文件 StudentDao.xml
- 要 StudentDao.xml 文件名称和接口 StudentDao 一样，区分大小写的一样
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| <?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.bytedance.dao.StudentDao">
<select id="selectStudents" resultType="com.bytedance.domain.Student">
select id,name,email,age from student
</select>
</mapper>
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创建Mybatis主配置文件
项目 src/main 下创建 resources 目录，设置 resources 目录为 resources root 创建主配置文件：名称为 mybatis.xml 说明：主配置文件名称是自定义的，内容如下
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| <?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="mysql">
<environment id="mysql">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/ssm"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/bytedance/dao/StudentDao.xml"/>
</mappers>
</configuration>
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创建测试类
src/test/java/com/bytedance/ 创建 MyBatisTest.java 文件
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@Test
public void testStart() throws IOException {
String config = "mybatis-config.xml";
InputStream in = Resources.getResourceAsStream(config);
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
SqlSession session = factory.openSession();
List<Student> studentList = session.selectList("com.bytedance.dao.StudentDao.selectStudents");
studentList.forEach( student -> System.out.println(student));
session.close();
}
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配置日志功能
mybatis.xml 文件加入日志配置，可以在控制台输出执行的 sql 语句和参数
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| <settings>
<setting name="logImpl" value="STDOUT_LOGGING" />
</settings>
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insert
StudentDao 接口中增加方法
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| int insertStudent(Student student);
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StudentDao.xml中加入SQL语句
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| （2） StudentDao.xml 加入 sql 语句
<insert id="insertStudent">
insert into student(id,name,email,age)
values(#{id},#{name},#{email},#{age})
</insert>
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增加测试方法
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| @Test
public void testInsert() throws IOException {
String config = "mybatis-config.xml";
InputStream in = Resources.getResourceAsStream(config);
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
SqlSession session = factory.openSession();
Student student = new Student();
student.setId(1005);
student.setName("张丽");
student.setEmail("zhangli@163.com");
student.setAge(20);
int rows = session.insert(
"com.bytedance.dao.StudentDao.insertStudent",student);
session.commit();
System.out.println("增加记录的行数:"+rows);
session.close();
}
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update
StudentDao接口中增加方法
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| int updateStudent(Student student);
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StudentDao.xml文件中增加SQL语句
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| <update id="updateStudent">
update student set age = #{age} where id=#{id}
</update>
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增加测试方法
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| @Test
public void testUpdate() throws IOException {
String config = "mybatis-config.xml";
InputStream in = Resources.getResourceAsStream(config);
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
SqlSession session = factory.openSession();
Student student = new Student();
student.setId(1005);
student.setAge(30);
int rows = session.update(
"com.bytedance.dao.StudentDao.updateStudent",student);
session.commit();
System.out.println("修改记录的行数:"+rows);
session.close();
}
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delete
StudentDao接口中增加方法
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| int deleteStudent(int id);
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StudentDao.xml文件中增加SQL语句
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| <delete id="deleteStudent">
delete from student where id=#{studentId}
</delete>
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增加测试方法
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| @Test
public void testDelete() throws IOException {
String config = "mybatis-config.xml";
InputStream in = Resources.getResourceAsStream(config);
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
SqlSession session = factory.openSession();
int id = 1001;
int rows = session.delete(
"com.bytedance.dao.StudentDao.deleteStudent",id);
session.commit();
System.out.println("修改记录的行数:"+rows);
session.close();
}
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