Mybatis基础
1.结构图
2.配置文件
-
jdbc
driver=com.mysql.jdbc.Driver url=jdbc:mysql://localhost:3306/db1 username=root password=root -
log4j(不是必须)
# Global logging configuration # ERROR WARN INFO DEBUG log4j.rootLogger=DEBUG, stdout # Console output... log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n -
MyBatisConfig
<?xml version="1.0" encoding="UTF-8" ?> <!--MyBatis的DTD约束--> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <!--configuration 核心根标签--> <configuration> <!--引入数据库连接的配置文件--> <properties resource="jdbc.properties"/> <!--配置LOG4J--> <settings> <setting name="logImpl" value="log4j"/> </settings> <!--起别名--> <typeAliases> <typeAlias type="com.ding.bean.Student" alias="student"/> <!--<package name="com.ding.bean"/>--> </typeAliases> <!--environments配置数据库环境，环境可以有多个。default属性指定使用的是哪个--> <environments default="mysql"> <!--environment配置数据库环境 id属性唯一标识--> <environment id="mysql"> <!-- transactionManager事务管理。 type属性，采用JDBC默认的事务--> <transactionManager type="JDBC"></transactionManager> <!-- dataSource数据源信息 type属性 连接池--> <dataSource type="POOLED"> <!-- property获取数据库连接的配置信息 --> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <!-- mappers引入映射配置文件 --> <mappers> <!-- mapper 引入指定的映射配置文件 resource属性指定映射配置文件的名称 --> <mapper resource="StudentMapper.xml"/> </mappers> </configuration> -
StudentMapper
<?xml version="1.0" encoding="UTF-8" ?> <!--MyBatis的DTD约束--> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <!-- mapper：核心根标签 namespace属性：名称空间 --> <mapper namespace="StudentMapper"> <!-- select：查询功能的标签 id属性：唯一标识 resultType属性：指定结果映射对象类型 parameterType属性：指定参数映射对象类型 --> <select id="selectAll" resultType="student"> select * from student </select> <select id="selectById" resultType="student" parameterType="int"> select * from student where id=#{id} </select> <insert id="insert" parameterType="student"> insert into student values(#{id},#{name},#{age}) </insert> <update id="update" parameterType="student"> update student set name=#{name},age=#{age} where id=#{id} </update> <delete id="delete" parameterType="int"> delete from student where id=#{id} </delete> </mapper>
3.实体类
package com.ding.bean;
public class Student {
private Integer id;
private String name;
private Integer age;
public Student() {
}
public Student(Integer id, String name, Integer age) {
this.id = id;
this.name = name;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name=‘" + name + ‘\‘‘ +
", age=" + age +
‘}‘;
}
}
4.测试类
package com.ding.dao;
import com.ding.bean.Student;
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 java.io.InputStream;
import java.util.List;
/**
* @Description TODO
* @Author 丁帅帅
* @Date 21/07/17 14:57
* @Version 1.0
*/
public class StudentTest01 {
/**
* 查询全部
*/
@Test
public void selectAll() throws Exception{
//1.加载核心配置文件
//InputStream is = Resources.getResourceAsStream("MyBatisConfig.xml");
InputStream is = StudentTest01.class.getClassLoader().getResourceAsStream("MyBatisConfig.xml");
//2.获取SqlSession工厂对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//3.通过SqlSession工厂对象获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession();
//4.执行映射配置文件中的sql语句，并接收结果
List<Student> list = sqlSession.selectList("StudentMapper.selectAll");
//5.处理结果
for (Student stu : list) {
System.out.println(stu);
}
//6.释放资源
sqlSession.close();
is.close();
}
/*
根据id查询
*/
@Test
public void selectById() throws Exception{
//1.加载核心配置文件
InputStream is = Resources.getResourceAsStream("MyBatisConfig.xml");
//2.获取SqlSession工厂对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//3.通过工厂对象获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession();
//4.执行映射配置文件中的sql语句,并接收结果
Student stu = sqlSession.selectOne("StudentMapper.selectById", 3);
//5.处理结果
System.out.println(stu);
//6.释放资源
sqlSession.close();
is.close();
}
/**
* 新增功能
*/
@Test
public void insert() throws Exception{
//1.加载核心配置文件
InputStream is = Resources.getResourceAsStream("MyBatisConfig.xml");
//2,获取SqlSession工厂对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//3.通过工厂对象获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession();
//4.执行映射配置文件中的sql语句,并接收结果
Student student = new Student(4, "周琦", 27);
int result = sqlSession.insert("StudentMapper.insert", student);
//5.提交事务
sqlSession.commit();
//6.处理结果
System.out.println(result);
//7.释放资源
sqlSession.close();
is.close();
}
/*
修改功能
*/
@Test
public void update() throws Exception{
//1.加载核心配置文件
InputStream is = Resources.getResourceAsStream("MyBatisConfig.xml");
//2.获取SqlSession工厂对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//3.通过工厂对象获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession(true);
//4.执行映射配置文件中的sql语句,并接收结果
Student student = new Student(4, "周七", 47);
int result = sqlSession.update("StudentMapper.update", student);
//5.处理结果
System.out.println(result);
//6.释放资源
sqlSession.close();
is.close();
}
/*
删除功能
*/
@Test
public void delete() throws Exception{
//1.加载核心配置文件
InputStream is = Resources.getResourceAsStream("MyBatisConfig.xml");
//2.获取SqlSession工厂对象
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//3.通过工厂对象获取SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession(true);
//4.执行映射配置文件中的sql语句,并接收结果
int result = sqlSession.delete("StudentMapper.delete", 4);
//5.处理结果
System.out.println(result);
//6.释放资源
sqlSession.close();
is.close();
}
}