java通过mybatis查询mysql服务

简单入门Java中实现mybatis访问数据库功能

1、        新建一个maven工程

2、        配置文件

Mapper.xml文件的配置：

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEmapperPUBLIC "-//mybatis.org//DTDMapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!--命名空间应该是对应接口的包名+类名 -->

<mappernamespace="spring.NeedDao">

    <!--id应该是接口中的方法，结果类型如没有配置别名则应该使用全名称 -->

Mybatis.xml文件的配置：

<?xmlversion="1.0"encoding="UTF-8"?>

<!DOCTYPEconfigurationPUBLIC"-//mybatis.org//DTDConfig 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-config.dtd">

<configuration>

    <typeAliases>

        <typeAliasalias="Need"type="spring.Need"/>

    </typeAliases>

 

    <environmentsdefault="development">

        <environmentid="development">

        <transactionManagertype="JDBC"/>

            <dataSourcetype="POOLED">

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

            <propertyname="url"value="jdbc:mysql://192.168.1.205:3306/oxiaomeng"/>

            <propertyname="username"value="root"/>

            <propertyname="password"value="root"/>

            </dataSource>

        </environment>

    </environments>

   

    <mappers>

        <mapperresource="mapper.xml"/>

    </mappers>

</configuration>

Log4j2.xml的文件配置：

<?xmlversion="1.0"encoding="UTF-8"?>

<Configurationstatus="off"monitorInterval="1800">

   <Appenders>

      <Consolename="Console"target="SYSTEM_OUT">

         <PatternLayoutpattern="%d{HH:mm:ss.SSS}[%t] %-5level %logger{36} - %msg%n"/>

      </Console>

   </Appenders>

 

   <Loggers>

      <Rootlevel="debug">

         <AppenderRefref="Console"/>

      </Root>

   </Loggers>

</Configuration>

3. 各种类的实现

public abstract class MybatisUtil {

    private static SqlSessionFactory factory=null;

    public static SqlSessionFactory getSqlSessionFactory(){

        if(factory==null){

        InputStream config = MybatisUtil.class.getClassLoader().getResourceAsStream("mybtis-config.xml");

        factory = new SqlSessionFactoryBuilder().build(config);

        }

        returnfactory;

    }

   

    public static SqlSession getSession(){

        returngetSqlSessionFactory().openSession(true);

    }

   

    public static SqlSession getSession(booleanisAutoCommit){

        returngetSqlSessionFactory().openSession(isAutoCommit);

   

}

}

import java.util.List;
public interface NeedDao {
public List<Need> getAllNeed();
}

public class Need {
int id;
String user_id;
String  latitude;
String longitude;
String need_code;
String text;
Date create_date;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUser_id() {
return user_id;
}
public void setUser_id(String user_id) {
this.user_id = user_id;
}
public String getLatitude() {
return latitude;
}
public void setLatitude(String latitude) {
this.latitude = latitude;
}
public String getLongitude() {
return longitude;
}
public void setLongitude(String longitude) {
this.longitude = longitude;
}
public String getNeed_code() {
return need_code;
}
public void setNeed_code(String need_code) {
this.need_code = need_code;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
public Date getCreate_date() {
return create_date;
}
public void setCreate_date(Date create_date) {
this.create_date = create_date;
}
}

 public class NeedImpl implements NeedDao{


@Override
public List<Need> getAllNeed() {
// TODO Auto-generated method stub
SqlSession session=MybatisUtil.getSession();
        try {
          
            NeedDao needDao=  session.getMapper(NeedDao.class);
            return needDao.getAllNeed();
        } finally {
            session.close();
        }
}


}

public class Main {
public static void main(String[] args){
NeedDao nd = new NeedImpl();
List<Need> need = nd.getAllNeed();
for(Need n : need){
System.out.println(n.getId()+n.getUser_id()+n.getCreate_date()+n.getNeed_code()+n.getLatitude()+n.getLongitude()+n.getText());
}
}
}