MyBatis 本是apache的一个开源项目iBatis, 2010年这个项目由apache software foundation 迁移到了google code，并且改名为MyBatis 。2013年11月迁移到Github。

MyBatis作为一款优秀的orm框架，经常与Hibernate拿来比较，身为目前较流行的MyBatis 避免了几乎所有的 JDBC 代码和手动设置参数以及获取结果集。接下来我们来看看如何搭建一个MyBaits项目。
因为idea并不支持mybatis的自动搭建，所以我们需要手动的导入一些jar包

需要准备的Jar包

mybatis-3.4.6.jar mybatis的主体
mysql-connector-java-5.1.46.jar 链接数据的
log4j-1.2.17 用于打印日志的

关于Mybatis的构建分为两种，我们先看XML方式

XML方式

1. Mybatis-configuration.xml

mybatis-configuration.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> <!-- 引入配置文件 --> <properties resource="db.properties"/> <!-- 设置打印使用log4j --> <settings> <setting name="logImpl" value="STDOUT_LOGGING"/> <setting name="logImpl" value="LOG4J"/> </settings> <!-- 设置运行时环境 --> <!-- mybatis 允许存在多个运行时环境 --> <environments default="development"> <environment id="development"> <!-- transactionManager 事务管理者 --> <!-- 设置本次事务管理方式为JDBC --> <transactionManager type="JDBC"/> <!-- 数据源 连接池 --> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${user}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <!-- 引入映射文件 --> <mappers> <mapper resource="model/UserMapper.xml"/> </mappers> </configuration> 

2.User.java以及UserMapper.xml

User.java

package model; /** * Created by Administrator on 2018/10/31. */ public class User { private int id; private String username; private String nickname; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public String getNickname() { return nickname; } public void setNickname(String nickname) { this.nickname = nickname; } @Override public String toString() { return "User{" + "id=" + id + ", username='" + username + '\'' + ", nickname='" + nickname + '\'' + '}'; } } 

UserMapper.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"> <!-- 命名空间 对自己取一个名字作为调用的唯一标识符--> <mapper namespace="model.UserMapper"> <!-- id sql语句的id 调用时使用命名空间+sqlid方式进行调用 --> <!-- parameterType 参数类型 --> <!-- resultType 返回值类型 --> <select id="selectUserById" parameterType="int" resultType="model.User"> <!-- 参数注入时使用#或$ --> <!-- #是占位符,在预编译时使用?占位,可以预防sql注入的问题 --> <!-- $是连接符,解析sql时直接使用变量替换,可能会引起sql注入的问题 --> <!-- #和$ 相当于 preparedStatement和statement的区别 --> <!-- 总的来说,能用#就别用$ --> select id,username,nickname from user where id = #{id} </select> </mapper> 

3.db.properties以及log4j.properties

db.properties

driver=com.mysql.jdbc.Driver url=jdbc:mysql:///test user=root password=root 

log4j.properties

log4j.rootLogger=DEBUG, stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=[service] %d - %c -%-4r [%t] %-5p %c %x - %m%n #log4j.appender.R=org.apache.log4j.DailyRollingFileAppender #log4j.appender.R.File=../logs/service.log #log4j.appender.R.layout=org.apache.log4j.PatternLayout #log4j.appender.R.layout.ConversionPattern=[service] %d - %c -%-4r [%t] %-5p %c %x - %m%n #log4j.logger.com.ibatis = debug #log4j.logger.com.ibatis.common.jdbc.SimpleDataSource = debug #log4j.logger.com.ibatis.common.jdbc.ScriptRunner = debug #log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate = debug #log4j.logger.java.sql.Connection = debug log4j.logger.java.sql.Statement = debug log4j.logger.java.sql.PreparedStatement = debug log4j.logger.java.sql.ResultSet =debug 

4. 测试一下

Main.java

import model.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.Reader; public class Main { public static void main(String[] args) throws IOException { //xml方式 //定义mybatis的配置文件的路径 String resource = "mybatis_config.xml"; //将配置文件转换为reader Reader reader = Resources.getResourceAsReader(resource); //使用sqlsessionfactorybuilder对配置文件进行加载 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader); //获取sqlsession SqlSession sqlSession = sqlSessionFactory.openSession(); User user = sqlSession.selectOne("model.UserMapper.selectUserById",1); System.out.println(user); } } 

最后看一下控制台的输出内容

[service] 2018-10-31 16:59:55,875 - org.apache.ibatis.logging.LogFactory -0 [main] DEBUG org.apache.ibatis.logging.LogFactory - Logging initialized using 'class org.apache.ibatis.logging.log4j.Log4jImpl' adapter. [service] 2018-10-31 16:59:56,047 - org.apache.ibatis.logging.LogFactory -172 [main] DEBUG org.apache.ibatis.logging.LogFactory - Logging initialized using 'class org.apache.ibatis.logging.log4j.Log4jImpl' adapter. [service] 2018-10-31 16:59:56,075 - org.apache.ibatis.datasource.pooled.PooledDataSource -200 [main] DEBUG org.apache.ibatis.datasource.pooled.PooledDataSource - PooledDataSource forcefully closed/removed all connections. [service] 2018-10-31 16:59:56,075 - org.apache.ibatis.datasource.pooled.PooledDataSource -200 [main] DEBUG org.apache.ibatis.datasource.pooled.PooledDataSource - PooledDataSource forcefully closed/removed all connections. [service] 2018-10-31 16:59:56,075 - org.apache.ibatis.datasource.pooled.PooledDataSource -200 [main] DEBUG org.apache.ibatis.datasource.pooled.PooledDataSource - PooledDataSource forcefully closed/removed all connections. [service] 2018-10-31 16:59:56,075 - org.apache.ibatis.datasource.pooled.PooledDataSource -200 [main] DEBUG org.apache.ibatis.datasource.pooled.PooledDataSource - PooledDataSource forcefully closed/removed all connections. [service] 2018-10-31 16:59:56,207 - org.apache.ibatis.transaction.jdbc.JdbcTransaction -332 [main] DEBUG org.apache.ibatis.transaction.jdbc.JdbcTransaction - Opening JDBC Connection [service] 2018-10-31 16:59:56,541 - org.apache.ibatis.datasource.pooled.PooledDataSource -666 [main] DEBUG org.apache.ibatis.datasource.pooled.PooledDataSource - Created connection 836514715. [service] 2018-10-31 16:59:56,541 - org.apache.ibatis.transaction.jdbc.JdbcTransaction -666 [main] DEBUG org.apache.ibatis.transaction.jdbc.JdbcTransaction - Setting autocommit to false on JDBC Connection [com.mysql.jdbc.JDBC4Connection@31dc339b] [service] 2018-10-31 16:59:56,543 - model.UserMapper.selectUserById -668 [main] DEBUG model.UserMapper.selectUserById - ==> Preparing: select id,username,nickname from user where id = ? [service] 2018-10-31 16:59:56,607 - model.UserMapper.selectUserById -732 [main] DEBUG model.UserMapper.selectUserById - ==> Parameters: 1(Integer) [service] 2018-10-31 16:59:56,640 - model.UserMapper.selectUserById -765 [main] DEBUG model.UserMapper.selectUserById - <== Total: 1 User{id=1, username='赵大鹏', nickname='死亡列车'} 

可以看到sql语句以及查询的结果都出来了，mybatis使用xml方式搭建完毕。