1.先下载Mybatis和mysql connecrt的jar包
下载地址：
链接: https://pan.baidu.com/s/1kVFfF8N 密码: ypkb
导入jar包，maven的话可以直接配置pom
2.建立目录
如图所示
1.configuration.xml
在根目录里面创建这个mybatis配置文件
代码为：
<?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>
<typeAliases>
<!-- 设置typeAlias是为了在AppMapper.xml中不用每次写全App类的路径，而是用App代替 -->
<typeAlias type="domain.App" alias="App" />
</typeAliases>
<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://222.201.145.215/nziotdb"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</dataSource>
</environment>
</environments>
<mappers>
<!-- 配置AppMapper.xml的路径 -->
<mapper resource="mapperXml/AppMapper.xml" />
</mappers>
</configuration>
其中里面配置了数据库服务器的地址，账号和密码，并且设置了映射文件mapperxml的路径
2.在domain下面建立实体类
package domain;
import java.io.Serializable;
public class App implements Serializable{
/**
*
*/
private String appId;
private String appDesc;
private String newestVersion;
private String newestVersionDesc;
private String url;
private String md5;
public String getAppId() {
return appId;
}
public void setAppId(String appId) {
this.appId = appId;
}
public String getAppDesc() {
return appDesc;
}
public void setAppDesc(String appDesc) {
this.appDesc = appDesc;
}
public String getNewestVersion() {
return newestVersion;
}
public void setNewestVersion(String newestVersion) {
this.newestVersion = newestVersion;
}
public String getNewestVersionDesc() {
return newestVersionDesc;
}
public void setNewestVersionDesc(String newestVersionDesc) {
this.newestVersionDesc = newestVersionDesc;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getMd5() {
return md5;
}
public void setMd5(String md5) {
this.md5 = md5;
}
public String toString() {
return "App [appId=" + appId + ", appDesc=" + appDesc
+ ", newestVersion=" + newestVersion + ", newestVersionDesc="
+ newestVersionDesc + ", url=" + url + ", md5=" + md5 + "]";
}
}
这个类即代表一个表，类里面的变量可以直接设置为何表里面的字段一致，不一致就要在映射文件里面设置对应关系
3.在mapperXml下面写映射文件
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org/DTD Mapper 3.0" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="mapper.AppMapper">
<resultMap type="App" id="appResultMap">
<id property="appId" column="app_id" />
<result property="appDesc" column="app_desc" />
<result property="newestVersion" column="newest_version" />
<result property="newestVersionDesc" column="newest_version_desc" />
<result property="url" column="url" />
<result property="md5" column="md5" />
</resultMap>
<!-- select语句 -->
<select id="selectUserByID" parameterType="int" resultMap="appResultMap">
select * from app_t where app_t.app_id = #{appId}
</select>
</mapper>
其中resultMap就设置了对应的关系，解决实体类的变量和数据库中字段不一致的问题
具体的sql语句也是在映射文件里面写，其中id代表的是对应的方法，parameterType就是传入变量的类型，resultMap就是返回的数据类型
4.在mapper下为每个实体类建立对应的接口，接口里面的方法和映射文件里面的id一一对应
package mapper;
import java.util.List;
import domain.App;
public interface AppMapper {
public App selectUserByID(int id);
public List<App> selectUsersByName(String userName);
public void addUser(App user);
public void updateUser(App user);
public void deleteUser(int id);
}
5.编写数据库查询帮助类，用于返回数据库对象
package Deal; import domain.App;
import mapper.AppMapper;
import org.apache.ibatis.session.SqlSession; public class Test{ public void getUserByID(int userID) {
SqlSession session = SqlSessionHelper.getSessionFactory().openSession();
try {
AppMapper userOperation = session
.getMapper(AppMapper.class);
App user = userOperation.selectUserByID(userID);
if (user != null) {
System.out.println(user.getAppDesc());
} } finally {
session.close();
}
} public static void main(String[] args) {
try {
Test test = new Test();
test.getUserByID(1);
} catch (Exception e) {
System.out.println(e.getMessage());
}
} }
数据库表如下，使用该教程之前需要先在数据库建立表
查询的是app_id,对应的app_desc
运行test，得到的接口也是3
6.附上demo工程，不清楚的同学可以参考一下
链接: https://pan.baidu.com/s/1dFqVtSX 密码: jb7j