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1、MyBatis 注解开发前的准备
1.1、MyBatis 常用注解
@Insert: 实现新增
@Update: 实现更新
@Delete: 实现删除
@Select: 实现查询
@Result: 实现结果集封装
@Results: 可以与 @Result 一起使用,封装多个结果集
@ResultMap: 实现引用 @Results 定义的封装
@One: 实现一对一结果集封装
@Many: 实现一对多结果集封装
@SelectProvider: 实现动态 SQL 映射
@CacheNamespace: 实现注解二级缓存的使用
1.2、注解开发前的准备
1.2.1、创建项目
GroupId:com.tyschool
ArtifactId:mb005
Version:1.0-SNAPSHOT
1.2.2、编写 pom.xml 配置文件
<?xml version="1.0" encoding="UTF-8"?>
<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.tyschool</groupId>
<artifactId>mb005</artifactId>
<version>1.0-SNAPSHOT</version>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.9</maven.compiler.source>
<maven.compiler.target>1.9</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.11</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>
1.2.3、编写 SqlMapConfig.xml 配置文件
<?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>
<properties resource="db.properties"></properties>
<settings>
<setting name="logImpl" value="STDOUT_LOGGING" />
</settings>
<typeAliases>
<package name="com.tyschool.mb005.javabean"/>
</typeAliases>
<environments default="mysql">
<environment id="mysql">
<transactionManager type="JDBC"></transactionManager>
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments>
</configuration>
数据源文件 db.properties
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://192.168.1.123:3306/mybatis?serverTimezone=UTC
jdbc.username=root
jdbc.password=Root12345
2、完成单表的 CRUD
2.1、需求介绍
完成学生表的 CRUD
2.2、编写 Students.java 文件
import java.io.Serializable;
public class Students implements Serializable {private int sid;
private String sname;
private String ssex;
private int sage;
private int cid;
public int getSid() {return sid;
}
public void setSid(int sid) {this.sid = sid;
}
public String getSname() {return sname;
}
public void setSname(String sname) {this.sname = sname;
}
public String getSsex() {return ssex;
}
public void setSsex(String ssex) {this.ssex = ssex;
}
public int getSage() {return sage;
}
public void setSage(int sage) {this.sage = sage;
}
public int getCid() {return cid;
}
public void setCid(int cid) {this.cid = cid;
}
@Override
public String toString() {return "Students{" +
"sid=" + sid +
", sname='" + sname + '\'' +
", ssex='" + ssex + '\'' +
", sage=" + sage +
", cid=" + cid +
'}';
}
}
2.3、编写 IStudentsDao.java 文件
import java.util.List;
import com.tianyi.javabean.Students;
public interface IStudentsDao {List<Students> findAll();
Students findById(int sid);
int addStudents(Students students);
int updateStudents(Students students);
int deleteStudents(int sid);
int addCount();
List<Students> findByName(String name);
}
配置映射
<mappers>
<package name="com.tyschool.mb005.students.dao"/>
</mappers>
2.4、创建测试类 MbStudentsTest.java
package com.tianyi.test;
import com.tianyi.dao.IStudentsDao;
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.After;
import org.junit.Before;
import java.io.IOException;
import java.io.InputStream;
public class MbStudentsTest {private InputStream in;
private SqlSession session;
private IStudentsDao studentsDao;
@Before
public void init()throws IOException {in= Resources.getResourceAsStream("SqlMapConfig.xml");
SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
SqlSessionFactory factory=builder.build(in);
session=factory.openSession(true);
studentsDao=session.getMapper(IStudentsDao.class);
}
@After
public void destroy() throws IOException {//session.commit();
session.close();
in.close();}
}
3、CRUD 操作 - 上
3.1、查询所有学生信息
3.1.1、修改 findAll() 方法
@Select("select * from students")
@Results(id="studentsMap",value={@Result(id=true,column = "sid",property = "sid"),
@Result(column = "sname",property = "sname"),
@Result(column = "ssex",property = "ssex"),
@Result(column = "sage",property = "sage")
})
List<Students> findAll();
3.3.2、编写测试方法
@Test
public void findAll(){List<Students> list=studentsDao.findAll();
for (Students s:list) {System.out.println(s);
}
}
3.2、根据 ID 查询学生信息
3.2.1、修改 findByID() 方法
@Select("select * from students where sid=#{sid}")
@ResultMap("studentsMap")
Students findById(int sid);
3.2.2、编写测试方法
@Test
public void findById(){Students s=studentsDao.findById(3);
System.out.println(s);
}
3.3、增加学生的记录
3.3.1、修改 addStudents() 方法
@Insert("insert into students(sname,ssex,sage)values(#{sname},#{ssex},#{sage})")
@SelectKey(keyColumn = "sid",keyProperty="sid",resultType = Integer.class,before = false,statement = {"select last_insert_id()"})
int addStudents(Students students);
3.3.2、编写测试方法
@Test
public void addStudents(){Students s=new Students();
s.setSname("张九");
s.setSsex("男");
s.setSage(19);
studentsDao.addStudents(s);
}
4、CRUD 操作 - 下
4.1、修改学生的信息
4.1.1、修改 updateStudents() 方法
@Update("update students set sname=#{sname},ssex=#{ssex},sage=#{sage} where sid=#{sid}")
int updateStudents(Students students);
4.1.2、编写测试方法
@Test
public void updateStudents(){Students s=studentsDao.findById(2);
s.setSname("李好");
studentsDao.updateStudents(s);
}
4.2、删除指定 ID 的学生信息
4.2.1、修改 deleteStudents() 方法
@Delete("delete from students where sid=#{sid}")
int deleteStudents(int sid);
4.2.2、编写测试方法
@Test
public void deleteStudents(){studentsDao.deleteStudents(9);
}
5、统计与模糊查询
5.1、查询学生表中所有记录
5.1.1、修改 addCount() 方法
@Select("select count(*) from students")
int addCount();
5.1.2、编写测试方法
@Test
public void addCount(){int n=studentsDao.addCount();
System.out.println(n);
}
5.2、通过学生姓名模糊查询学生信息
5.2.1、修改 findByName() 方法
@Select("select * from students where sname like #{sname}")
List<Students> findByName(String sname);
5.2.2、编写测试方法
@Test
public void findByName(){List<Students> list =studentsDao.findByName("李 %");
for(Students s:list){System.out.println(s);
}
}
正文完
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