第一步:打開eclipse,新建maven項目,勾選第一個(creat a simple….)
第二步:打開pom.xml文件,爲其添加常用配置
<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>4.0.0</modelVersion>
<groupId>tk.mybatis</groupId>
<artifactId>simple</artifactId>
<version>0.0.1-SNAPSHOT</version>
<properties>
<java.version>1.8</java.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.3.0</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.12</version>
</dependency>
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.12</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
</configuration>
</plugin>
</plugins>
</build>
</project>
然後 alt+F更新外部依賴的jar包
第三步:準備數據庫
創建一個country表{
id
countryname
countrycode
}其中id爲主鍵,不爲空
並插入幾個數據。
第四步:配置mybatis
在src/main/resouces下面創建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="LOG4J"/>
</settings>
<typeAliases>
<package name="tk.mybatis.simple.model"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC">
<property name="" value=""/>
</transactionManager>
<dataSource type="UNPOOLED">
<property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
<property name="url" value="jdbc:oracle:thin:@localhost:1521:XE"/>
<property name="username" value="mybatis"/>
<property name="password" value="mybatis"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="tk/mybatis/simple/mapper/CountryMapper.xml"/>
</mappers>
</configuration>
這裏注意,筆者的mysql數據庫沒有連接成功,所以換用了oracle數據庫,前面的配置的依賴mysql-connector換成oracle既可,也可以將這裏的數據庫配置換成mysql的。
簡單講解一下以上配置的大概意思
中的logImpl屬性配置指定的LOG4J輸出日誌
元素配置了一個包的別名,通常確定一個類的時候需要使用類的全限定名稱,在mybatis中需要頻繁使用這種全限定名稱,爲了方便使用,這樣配置後,使用類的時候直接使用Country
environment這個不解釋
mappers中配置了一個包含完整路徑的xml文件,這是一個mybatis的sql語句和映射配置文件。
第五步:創建實體類
在src/main/java下創建一個Country實體類
第六步:在src/main/resouce下面創建CountryMapper.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" >
<mapper namespace="tk.mybatis.simple.mapper.CountryMapper">
<select id="selectAll" resultType="Country">
select id,countryname,countrycode from country
</select>
</mapper>
第七步:
配置log4j查看mybatis操作數據庫的過程
在src/main/resouces創建log4j.propertoes文件
#全局配置
log4j.rootLogger=ERROR, stdout
#mybatis日誌配置
log4j.logger.tk.mybatis.simple.mapper=TRACE
#控制檯輸出配置
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
第八步:測試類
package tk.mybatis.simple.mapper;
import java.io.IOException;
import java.io.Reader;
import java.util.List;
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 org.junit.BeforeClass;
import org.junit.Test;
import tk.mybatis.simple.model.Country;
public class CountryMapperTest {
private static SqlSessionFactory sqlSessionFactory;
@BeforeClass
public static void init(){
try {
Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
reader.close();
} catch (IOException ignore) {
ignore.printStackTrace();
}
}
@Test
public void testSelectAll(){
SqlSession sqlSession = sqlSessionFactory.openSession();
try {
List<Country> countryList = sqlSession.selectList("selectAll");
printCountryList(countryList);
} finally {
sqlSession.close();
}
}
private void printCountryList(List<Country> countryList){
for(Country country : countryList){
System.out.printf("%-4d%4s%4s\n",country.getId(), country.getCountryname(), country.getCountrycode());
}
}
}
通過Resources工具類將mybatis-config.xml配置文件讀入
然後創建SqlSessionFactory工廠對象
然後獲取一個sqlsession
查詢處理:
關閉sqlsession