Mybatis系列一之入门

myBatis通过xml文件来配置数据库

1 idea中整体maven结构

注意事项：

• 事项一： 文件包创建时注意第二种是错误的做法，com->xgh->dao一级一级的创建

2 idea中myBatis的配置项目

2.1 配置pom.xml

<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>4.0.0modelVersion>

    <groupId>org.examplegroupId>
    <artifactId>mybatis_xmlartifactId>
    <version>1.0-SNAPSHOTversion>
    
    <packaging>jarpackaging>
    <dependencies>
        
        <dependency>
            <groupId>org.mybatisgroupId>
            <artifactId>mybatisartifactId>
            <version>3.4.0version>
        dependency>
        
        <dependency>
            <groupId>mysqlgroupId>
            <artifactId>mysql-connector-javaartifactId>
            <version>8.0.22version>
        dependency>
        
        <dependency>
            <groupId>junitgroupId>
            <artifactId>junitartifactId>
            <version>4.13.1version>
            <scope>testscope>
        dependency>

        
        <dependency>
            <groupId>log4jgroupId>
            <artifactId>log4jartifactId>
            <version>1.2.12version>
        dependency>
    dependencies>
project>

2.2 配置resources下SqlMapConfig.xml

本人采用的数据库是mysql8版本的

<configuration>

<properties>
    <property name="driver" value="com.mysql.cj.jdbc.Driver">property>
    <property name="url" value="jdbc:mysql://localhost:3306/db1?userSSL=false&serverTimezone=UTC">property>
    <property name="username" value="root">property>
    <property name="password" value="cmsxgh">property>
properties>

<environments default="mysql">
    
    <environment id="mysql">
        
        <transactionManager type="JDBC">transactionManager>

        
        <dataSource type="POOLED">
            <property name="driver" value="${driver}">property>
            <property name="url" value="${url}">property>
            <property name="username" value="${username}">property>
            <property name="password" value="${password}">property>
        dataSource>
    environment>
environments>

<mappers>
    <mapper resource="com/xgh/dao/IUserDao.xml">mapper>
mappers>
configuration>

• 注意事项
  1 mysql8 连接时driver和url和mysql5 的区别
  

2.3 配置com.xgh.dao下IUserDao.xml

<mapper namespace="com.xgh.dao.IUserDao">
    
    <select id="findAll" resultType="com.xgh.domain.User">
        select * from user
    select>
mapper>

测试类

import com.xgh.dao.IUserDao;
import com.xgh.domain.User;
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;
import java.util.List;

public class mybatisTest {
     
    public static void main(String[] args) throws IOException {
     
        //1 读取配置文件
        InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");

        //2 创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory build = builder.build(is);
//        SqlSessionFactory build = builder.build(is);

        //3 使用工厂生产SqlSession对象
        SqlSession session = build.openSession();

        //4 使用SqlSession创建Dao接口的代理对象
        IUserDao userDao = session.getMapper(IUserDao.class);

        //5 使用代理对象执行方法
        List<User> users = userDao.findAll();
        for (User user : users) {
     
            System.out.println(user);
        }
        //6 释放对象
        session.close();
        is.close();
    }
}

相关配置文件

1 log4j.properties

# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE            debug   info   warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n

运行结果