方式清单

（先将jar包导完后）

• 方式一

  思路

  1. 将数据库连接有关的信息配置到db.properties里
  2. 为了方便跟进程序，在mybatis-config.xml中将mybatis的自带日志打开
  3. 在applicationContext.xml中配置数据源、sqlSessionFactory、自动扫描对象关系映射等
  4. 建立包：entities、dao、mapper、service、service.impl，并创建相应类或接口

  代码

  整体目录结构：

  
  
  最终目录结构

配置db.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://127.0.0.1:3306/xzl?useUnicode=true&characterEncoding=utf8
jdbc.username=aaa
jdbc.password=123

配置mybatis-config.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>

    <settings>
        <setting name="logImpl" value="STDOUT_LOGGING" />
    </settings>
    
</configuration>

配置applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context 
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <!-- 导入外部配置文件 -->
    <context:property-placeholder location="db.properties"/>
    
    <!-- 配置service的实现类 -->
    <bean name="qqun_ListService" class="demo.cyj.service.impl.Qqun_ListServiceImpl"></bean>
    
    
    <!-- 数据源配置 -->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="${jdbc.driver}"></property>
        <property name="url" value="${jdbc.url}"></property>
        <property name="username" value="${jdbc.username}"></property>
        <property name="password" value="${jdbc.password}"></property>
    </bean>

    <!-- sqlSessionFactory给spring托管 -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <!-- 数据源 -->
        <property name="dataSource" ref="dataSource"></property>
        <!-- 别名,类名开头变小写 -->
        <property name="typeAliasesPackage"  value="demo.cyj.entities"></property>
        <!-- sql映射文件路径 -->
        <!-- classpath *和不加*的区别 -->
        <property name="mapperLocations" value="classpath*:demo/cyj/mapper/*Mapper.xml"></property>
        <property name="configLocation" value="classpath:mybatis-config.xml"></property>
    </bean>

          <!--自动扫描对象关系映射 -->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!--指定会话工厂，如果当前上下文中只定义了一个则该属性可省去 -->
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>
        <!-- 指定要自动扫描接口的基础包，实现接口 -->
        <property name="basePackage" value="demo.cyj.dao"></property>
    </bean>
    

</beans>

实体类Q群列表：Qqun_List.java

package demo.cyj.entities;

import java.io.Serializable;

public class Qqun_List implements Serializable{
    
    private static final long serialVersionUID = -8969192680204852279L; 
    
    private String  groupId;
    private String  groupName;
    private String  auth;
    private String  flag;
    
    public Qqun_List() {}
    
    public Qqun_List(String groupId, String groupName, String auth, String flag) {
        super();
        this.groupId = groupId;
        this.groupName = groupName;
        this.auth = auth;
        this.flag = flag;
    }
    public String getGroupId() {
        return groupId;
    }
    public void setGroupId(String groupId) {
        this.groupId = groupId;
    }
    public String getGroupName() {
        return groupName;
    }
    public void setGroupName(String groupName) {
        this.groupName = groupName;
    }
    public String getAuth() {
        return auth;
    }
    public void setAuth(String auth) {
        this.auth = auth;
    }
    public String getFlag() {
        return flag;
    }
    public void setFlag(String flag) {
        this.flag = flag;
    }
    @Override
    public String toString() {
        return "Qqun_List [groupId=" + groupId + ", groupName=" + groupName + ", auth=" + auth + ", flag=" + flag + "]";
    }
}

dao接口Qqun_ListDao.java

package demo.cyj.dao;

import java.util.List;

import demo.cyj.entities.Qqun_List;

public interface Qqun_ListDao {

    public List<Qqun_List> findAll();
    
}

配置mapper文件Qqun_ListMapper.xml

<?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">

<!--此处的namespace需要和 接口的路径绑定 -->
<mapper namespace="demo.cyj.dao.Qqun_ListDao">
    <select id="findAll" resultType="qqun_List">
        select * from qqun_list
    </select>
</mapper>

service接口Qqun_ListService.java

package demo.cyj.service;

import java.util.List;

import demo.cyj.entities.Qqun_List;

public interface Qqun_ListService {
    public List<Qqun_List> findAll();   
}

service接口实现类Qqun_ListServiceImpl.java

package demo.cyj.service.impl;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;

import demo.cyj.dao.Qqun_ListDao;
import demo.cyj.entities.Qqun_List;
import demo.cyj.service.Qqun_ListService;

public class Qqun_ListServiceImpl implements Qqun_ListService{
    @Autowired
    private Qqun_ListDao qqun_ListDao;
    @Override
    public List<Qqun_List> findAll() {
        // TODO Auto-generated method stub
        return qqun_ListDao.findAll();
    }
}

编写测试类Test1.java

package demo.cyj;

import java.util.List;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import demo.cyj.entities.Qqun_List;
import demo.cyj.service.Qqun_ListService;

public class Test1 {
    public static void main(String[] args) {
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        Qqun_ListService qqun_ListService =  ac.getBean(Qqun_ListService.class);//单例才能这样传类类型
        List<Qqun_List> list = qqun_ListService.findAll();
        System.out.println(list);
    }   
}

运行结果

后面的明天写了

• 方式二

• 方式三

• 方式四