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mybatis初学-操作数据库查询数据

2020-09-18 14:31:47  阅读:159  来源: 互联网

标签:String 数据库 log4j 初学 import mybatis org public


第一步:使用idea创建一个maven项目

第二步:配置pom.xml,配置maven项目所需依赖

<?xml version="1.0" encoding="UTF-8"?>
<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>com.lun</groupId>
<artifactId>mybatis</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.12</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
</project>

第三步:创建实体类User
package com.lun.mybatis.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String sex;
private String address;

public User() {
}

public User(Integer id, String username, Date birthday, String sex, String address) {
this.id = id;
this.username = username;
this.birthday = birthday;
this.sex = sex;
this.address = address;
}

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

public Date getBirthday() {
return birthday;
}

public void setBirthday(Date birthday) {
this.birthday = birthday;
}

public String getSex() {
return sex;
}

public void setSex(String sex) {
this.sex = sex;
}

public String getAddress() {
return address;
}

public void setAddress(String address) {
this.address = address;
}

@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", birthday=" + birthday +
", sex='" + sex + '\'' +
", address='" + address + '\'' +
'}';
}
}

  第四步:创建接口持久层userdao.java,并使用注解select

           

package com.lun.mybatis.Dao;

import com.lun.mybatis.domain.User;
import jdk.nashorn.internal.objects.annotations.Setter;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface IUserDao {
//持久层接口
@Select("select * from user")
List<User> findUser();
}

 

 

  第五步:配置log4j并放在resource文件夹下,及配置mybatis主配置文件 sqlMapConfig

    log4j.properties:

    

# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=DEBUG, CONSOLE
log4j.rootCategory= ERROR, CONSOLE, LOGFILE
log4j.logger.com.leesun.mapper.FlowerMapper=DEBUG
# 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.Threshold=DEBUG
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%p %d{YYYY-MM-dd hh:mm:ss} 第%L行 %m %n

# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.Threshold=INFO
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout

    sqlMapConfig.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">
<!-- mybatis的主配置文件 -->
<configuration>
<!-- 这里写配置内容 -->
<environments default="mysql">
<!-- 配置mysql环境 -->
<environment id="mysql">
<!-- 配置事务类型 -->
<transactionManager type="JDBC"></transactionManager>
<!-- 配置数据源(连接池) -->
<dataSource type="POOLED">
<!-- 配置连接数据库的4个基本信息 -->
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatic?characterEncoding=utf8"/>
<property name="username" value="root"/>
<property name="password" value="88888888"/>
</dataSource>
</environment>
</environments>
<!-- 指定映射配置文件的位置,映射配置文件指的是每个dao独立的配置文件 -->
<mappers>
<mapper class="com.lun.mybatis.Dao.IUserDao"></mapper>
</mappers>
</configuration>

    第6步:添加test测试类进行测试

               

package com.lun.mybatis;
import com.lun.mybatis.Dao.IUserDao;
import com.lun.mybatis.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.InputStream;
import java.util.List;

public class MybatisTest {
public static void main(String[] args) throws Exception{
//读取配置文件
InputStream in = Resources.getResourceAsStream("sqlMapConfig.xml");
//创建sqlseesionFactory工厂
SqlSessionFactoryBuilder builder=new SqlSessionFactoryBuilder();
SqlSessionFactory factory=builder.build(in);
//使用工厂生产sqlsession对象
SqlSession sqlSession=factory.openSession();
//使用sqlsession创建dao接口的代理对象
IUserDao userDao =sqlSession.getMapper(IUserDao.class);
//使用代理对象执行方法
List<User> users=userDao.findUser();
for(User user:users){
System.out.println(user);
}
//释放资源
sqlSession.close();
in.close();
}
}

标签:String,数据库,log4j,初学,import,mybatis,org,public
来源: https://www.cnblogs.com/liuyilun/p/13691082.html

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