一小时迅速入门Mybatis之bind与多数据源支持 Java API

// 测试bind

List<Person> testBind( @Param ( "name" ) String name);

<!--测试bind-->

<!--相当于SQL select * from person where name like '%小强%' -->

< select id = "testBind" resultType = "entity.Person" >

     < bind name = "bidname" value = "'%'+name+'%'" />

     select * from person where name like #{bidname}

</ select >

import dao.PersonMapper;

import entity.Person;

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.InputStream;

import java.util.*;

/**

  * @author 发现更多精彩  关注公众号：木子的昼夜编程

  * 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作

  */

public class TestMain03 {

     public static void main(String[] args) throws Exception {

         String resource = "mybatis-config.xml" ;

         InputStream inputStream = Resources.getResourceAsStream(resource);

         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

         try (SqlSession session = sqlSessionFactory.openSession()) {

             // 通过sesson获取Mapper 这个Mapper会编程Mybatis的代理Mapper

             PersonMapper mapper = session.getMapper(PersonMapper. class );

             List<Person> list = mapper.testBind( "小强" );

             Optional.ofNullable(list).orElse( new ArrayList<>()).forEach(item -> {

                 System.out.println(item);

             });

         }

     }

}

<? xml version = "1.0" encoding = "UTF-8" ?>

< project xmlns = "http://maven.apache.org/POM/4.0.0"

          xmlns:xsi = "http://HdhCmsTestw3.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 >org.example</ groupId >

     < artifactId >testDB</ artifactId >

     < version >1.0-SNAPSHOT</ version >

     < properties >

         < maven测试数据piler.source >8</ maven测试数据piler.source >

         < maven测试数据piler.target >8</ maven测试数据piler.target >

     </ properties >

     < dependencies >

         <!-- 引入Mybatis -->

         < dependency >

             < groupId >org.mybatis</ groupId >

             < artifactId >mybatis</ artifactId >

             < version >3.4.5</ version >

         </ dependency >

         <!-- mysql-->

         < dependency >

             < groupId >mysql</ groupId >

             < artifactId >mysql-connector-java</ artifactId >

             < version >5.1.47</ version >

         </ dependency >

     </ dependencies >

</ project >

<? 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 = "development" >

         < environment id = "development" >

             < transactionManager type = "JDBC" />

             < dataSource type = "POOLED" >

                 < property name = "driver" value = "com.mysql.jdbc.Driver" />

                 < property name = "url" value = "jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false&amp;serverTimezone=GMT%2B8" />

                 < property name = "username" value = "root" />

                 < property name = "password" value = "123456" />

             </ dataSource >

         </ environment >

     </ environments >

     <!--DB_VENDOR是默认实现  这里可以定义自己的实现类 下一篇写-->

     < databaseIdProvider type = "DB_VENDOR" >

         <!--这里是因为原名称太长了 指定一下缩写 xml中判断类型就用缩写名称判断-->

         < property name = "DB2" value = "db2" />

         < property name = "Oracle" value = "oracle" />

         < property name = "Adaptive Server Enterprise" value = "sybase" />

         < property name = "MySQL" value = "mysql" />

     </ databaseIdProvider >

     <!--扫描-->

     < mappers >

         < mapper resource = "PersonMapper.xml" />

     </ mappers >

</ configuration >

package dao;

/**

  * @author 发现更多精彩  关注公众号：木子的昼夜编程  分享一个生活在互联网底层做着增删改查的码农的感悟与学习

  * @create 2021-08-30 21:54

  */

public interface PersonMapper {

     // 测试返回当前时间

     String testDb();

}

<? 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 = "dao.PersonMapper" >

     <!--选择不同的数据库-->

     < select id = "testDb" resultType = "string" >

         <!--如果是mysql 执行这个 -->

         < if test = "_databaseId == 'mysql'" >

             select CONCAT("mysql-->",#{_databaseId},"-->",now()) from dual

         </ if >

         <!--如果是oracle 执行这个-->

         < if test = "_databaseId == 'oracle'" >

             select "oracle-->"||#{_databaseId}  from dual

         </ if >

     </ select >

</ mapper >

import dao.PersonMapper;

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.InputStream;

/**

  * @author 发现更多精彩  关注公众号：木子的昼夜编程

  * 一个生活在互联网底层，做着增删改查的码农,不谙世事的造作

  * @create 2021-09-02 21:42

  */

public class TestMain {

     public static void main(String[] args) throws Exception {

         String resource = "mybatis-config.xml" ;

         InputStream inputStream = Resources.getResourceAsStream(resource);

         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

         SqlSession session = sqlSessionFactory.openSession();

             // 通过sesson获取Mapper 这个Mapper会编程Mybatis的代理Mapper

             PersonMapper mapper = session.getMapper(PersonMapper. class );

             String type = mapper.testDb();

             System.out.println( "数据库类型：" +type);

     }

}