MyBatis（注解方式操作）

文章目录

- 1.注解方式操作
- - - 文件目录
    - 1.快速入门（完整步骤）
    - - 1.pom.xml（完整）
      - 2.resources/jdbc.properties外部配置文件（根据实际情况修改参数）
      - 3.在resources/mybatis-config.xml（完整）中配置含有注解的接口
      - 4.映射类Monster.java
      - 5.编写MonsterAnnotation.java接口
      - 6.MyBatisUtils.java
      - 7.测试
    - 2.注意事项和细节
    - - 1.复制sql语句
      - 2.使用注解方式也要在配置文件中引入这个类！
      - 3.返回自增值（update和insert适用）
      - 4.配置SQL提示
- 2.MyBatis配置文件详解
- - - 1.外部属性文件设置相关的值
    - - 1.resources/jdbc.properties
      - 2.修改mybatis-config.xml引入外部文件
    - 2.settings配置日志
    - 3.typeAliases配置类型别名
    - 4.environments注册XXXMapper.xml或者含有注解的类
    - 5.pom.xml配置在build的时候要扫描的文件

1.注解方式操作

文件目录

1.快速入门（完整步骤）

1.pom.xml（完整）

<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/maven-v4_0_0.xsd"><modelVersion>4.0.0</modelVersion><groupId>org.example</groupId><artifactId>mybatis</artifactId><version>1.0-SNAPSHOT</version><packaging>pom</packaging><name>Archetype - mybatis</name><url>http://maven.apache.org</url><modules><module>mybatis_quickstart</module></modules><dependencies><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.49</version></dependency><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.7</version></dependency><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version><!--如果设置scope为test,则只能在test包下使用--><scope>test</scope></dependency></dependencies><!--在父模块中的pom.xml文件中配置在build的时候要扫描的文件，解决某些类型文件拷贝到target目录失败的问题--><build><resources><resource><directory>src/main/java</directory><includes><!--在java文件夹下的多级目录下的xml文件--><include>**/*.xml</include></includes></resource><resource><directory>src/main/resources</directory><includes><!--在resources文件夹下的多级目录下的xml文件和properties文件--><include>**/*.xml</include><include>**/*.properties</include></includes></resource></resources></build>
</project>

2.resources/jdbc.properties外部配置文件（根据实际情况修改参数）

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8
jdbc.username=root
jdbc.password=root

3.在resources/mybatis-config.xml（完整）中配置含有注解的接口

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--引入外部文件jdbc.properties--><properties resource="jdbc.properties"/><!--配置mybatis自带的日志，settings需要放到最前面--><settings><setting name="logImpl" value="STDOUT_LOGGING"/></settings><environments default="development"><environment id="development"><!--配置事务管理器--><transactionManager type="JDBC"/><!--配置数据源--><dataSource type="POOLED"><!--配置驱动--><property name="driver" value="${jdbc.driver}"/><!--配置连接url--><!--1.jdbc:mysql：协议2.127.0.0.1:3306：指定连接mysql的ip+端口3.mybatis：连接的db4.useSSL：使用安全连接5.&amp;：表示&6.useUnicode=true：使用unicode,防止编码错误7.characterEncoding=UTF-8：字符集使用utf-8--><property name="url" value="${jdbc.url}"/><!--用户名--><property name="username" value="${jdbc.username}"/><!--密码--><property name="password" value="${jdbc.password}"/></dataSource></environment></environments><mappers><!--包的方式引入含有注解的类--><package name="com.sun.mapper"/></mappers></configuration>

4.映射类Monster.java

package com.sun.entity;import java.util.Date;/*** @author 孙显圣* @version 1.0*/
public class Monster {private Integer id;private Integer age;private Date birthday;private String email;private Integer gender;private String name;private Double salary;//无参构造器public Monster() {}public Monster(Integer id, Integer age, Date birthday, String email, Integer gender, String name, Double salary) {this.id = id;this.age = age;this.birthday = birthday;this.email = email;this.gender = gender;this.name = name;this.salary = salary;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Date getBirthday() {return birthday;}public void setBirthday(Date birthday) {this.birthday = birthday;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}public Integer getGender() {return gender;}public void setGender(Integer gender) {this.gender = gender;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Double getSalary() {return salary;}public void setSalary(Double salary) {this.salary = salary;}@Overridepublic String toString() {return "Monster{" +"id=" + id +", age=" + age +", birthday=" + birthday +", email='" + email + '\'' +", gender=" + gender +", name='" + name + '\'' +", salary=" + salary +'}';}
}

5.编写MonsterAnnotation.java接口

package com.sun.mapper;import com.sun.entity.Monster;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;import java.util.List;/*** @author 孙显圣* @version 1.0*/
public interface MonsterAnnotation {@Insert("INSERT INTO `monster`(`id`,`age`,`birthday`,`email`,`gender`,`name`,`salaary`) " +"VALUES(NULL, #{age}, #{birthday}, #{email}, #{gender}, #{name}, #{salary})")public void addMonster(Monster monster);@Delete("DELETE FROM `monster` where id = #{id}")public void delMonster(Integer id);@Update("UPDATE `monster` SET " +"`age` = #{age}, `birthday` = #{birthday}, " +"`email` = #{email}, `name` = #{name}, `salary` = #{salary} " +"WHERE `id` = #{id}")public void updateMonster(Monster monster);@Select("SELECT * FROM `monster` WHERE id = #{id}")public Monster getMonsterById(Integer id);@Select("SELECT * FROM `monster`")public List<Monster> findAllMonster();}

6.MyBatisUtils.java

package com.util;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 java.io.IOException;
import java.io.InputStream;/*** @author 孙显圣* @version 1.0*/
public class MyBatisUtils {private static SqlSessionFactory sqlSessionFactory;//使用静态代码块初始化SqlSessionFactorystatic {try {//获取Mybatis配置文件的输入流String resource = "mybatis-config.xml";//默认是从类路径下获取资源，在maven中指的就是resources文件夹下，会映射到实际的工作目录InputStream resourceAsStream = Resources.getResourceAsStream(resource);//读取资源获取SessionFactory，可以理解为连接池sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);} catch (IOException e) {throw new RuntimeException(e);}}//编写方法返回SqlSessionpublic static SqlSession getSqlSession() {return sqlSessionFactory.openSession();}
}

7.测试

import com.sun.entity.Monster;
import com.sun.mapper.MonsterAnnotation;
import com.sun.mapper.MonsterMapper;
import com.util.MyBatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Before;
import org.junit.Test;import java.util.Date;
import java.util.List;/*** @author 孙显圣* @version 1.0*/
public class MonsterAnnotationTest {//两个属性private SqlSession sqlSession; //相当于连接private MonsterAnnotation monsterAnnotation;//编写方法完成初始化@Before //标注了Before之后表示了在执行目标测试方法前会执行该方法public void init() {//获取到sqlSessionsqlSession = MyBatisUtils.getSqlSession();//获取到代理对象monsterAnnotation = sqlSession.getMapper(MonsterAnnotation.class);}@Testpublic void addMonster() {for (int i = 0; i < 2; i++) {Monster monster = new Monster(null, 10 + i, new Date(), "sun@qq.com", 0, "孙显圣", 10.0 + i);//代理对象执行接口的方法monsterAnnotation.addMonster(monster);}//如果是增删改还要提交一下事务if (sqlSession != null) {sqlSession.commit();//将连接放回连接池sqlSession.close();}System.out.println("成功");}@Testpublic void find() {List<Monster> allMonster = monsterAnnotation.findAllMonster();for (Monster monster : allMonster) {System.out.println(monster);}if (sqlSession != null) {//将连接放回连接池sqlSession.close();}}}

2.注意事项和细节

1.复制sql语句

如果有/n则将这个/n去掉然后替换成空格
如果一行的前面有很多空格，就将这些空格都去掉

2.使用注解方式也要在配置文件中引入这个类！

3.返回自增值（update和insert适用）

自增值对应的列如果与属性名相同则可以省略

4.配置SQL提示

2.MyBatis配置文件详解

1.外部属性文件设置相关的值

1.resources/jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8
jdbc.username=root
jdbc.password=root

2.修改mybatis-config.xml引入外部文件

2.settings配置日志

3.typeAliases配置类型别名

4.environments注册XXXMapper.xml或者含有注解的类

5.pom.xml配置在build的时候要扫描的文件

  <!--在父模块中的pom.xml文件中配置在build的时候要扫描的文件，解决某些类型文件拷贝到target目录失败的问题--><build><resources><resource><directory>src/main/java</directory><includes><!--在java文件夹下的多级目录下的xml文件--><include>**/*.xml</include></includes></resource><resource><directory>src/main/resources</directory><includes><!--在resources文件夹下的多级目录下的xml文件和properties文件--><include>**/*.xml</include><include>**/*.properties</include></includes></resource></resources></build>