文件结构
数据库文件
CREATE TABLE `user` (
`id` int(11) NOT NULL auto_increment,
`username` varchar(32) NOT NULL COMMENT '用户名称',
`birthday` datetime default NULL COMMENT '生日',
`sex` char(1) default NULL COMMENT '性别',
`address` varchar(256) default NULL COMMENT '地址',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into `user`(`id`,`username`,`birthday`,`sex`,`address`) values (41,'老王','2018-02-27 17:47:08','男','北京'),(42,'小二王','2018-03-02 15:09:37','女','北京金燕龙'),(43,'小二王','2018-03-04 11:34:34','女','北京金燕龙'),(45,'传智播客','2018-03-04 12:04:06','男','北京金燕龙'),(46,'老王','2018-03-07 17:37:26','男','北京'),(48,'小马宝莉','2018-03-08 11:44:00','女','北京修正');
user表视图
pom文件
<?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.itcast</groupId>
<artifactId>day01_mybatis</artifactId>
<version>1.0-SNAPSHOT</version>
<!--打包方式-->
<packaging>jar</packaging>
<!--导入坐标依赖-->
<dependencies>
<!--mybatis坐标-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.5</version>
</dependency>
<!--数据库坐标-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
</dependency>
<!--log4j日志坐标-->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.12</version>
</dependency>
<!--junit单元测试坐标-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.10</version>
</dependency>
</dependencies>
</project>
mybatis主配置文件 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">
<!-- mybtis的主配置文件 -->
<configuration>
<!--配置环境-->
<environments default="mysql">
<!--配置mysql环境-->
<environment id="mysql">
<!--配置数据类型-->
<transactionManager type="JDBC"></transactionManager>
<!--配置数据源,也叫连接池-->
<dataSource type="POOLED">
<!--配置连接数据库的四个基本信息-->
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</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>
<!--resouce指的是映射配置文件位置,即IUserDao.xml文件的位置
如果是用注解来配置的话,此处应该使用class属性指定被注解的dao全限定类名-->
<!-- <mapper resource="com/itheima/dao/IUserDao.xml"/>-->
<mapper class="com.itheima.dao.IUserDao"/>
</mappers>
</configuration>
日志文件 log4j
# Set root category priority to INFO and its only appender to CONSOLE.
#log4j.rootCategory=INFO, CONSOLE debug info warn error fatal
log4j.rootCategory=debug, CONSOLE, LOGFILE
# 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.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
# LOGFILE is set to be a File appender using a PatternLayout.
log4j.appender.LOGFILE=org.apache.log4j.FileAppender
log4j.appender.LOGFILE.File=d:\axis.log
log4j.appender.LOGFILE.Append=true
log4j.appender.LOGFILE.layout=org.apache.log4j.PatternLayout
log4j.appender.LOGFILE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m\n
domain下的User文件
package com.itheima.domain;
import java.io.Serializable;
import java.util.Date;
public class User implements Serializable {
private String id ;
private String username ;
private Date birthday ;
private String sex ;
private String address ;
public String getId() {
return id;
}
public void setId(String 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 + '\'' +
'}';
}
}
dao下的接口文件 IUserDao
package com.itheima.dao;
import com.itheima.domain.User;
import org.apache.ibatis.annotations.Select;
import java.util.List;
/*
* 用户的持久层接口
* */
public interface IUserDao {
//查询所有操作
@Select("select * from user ")
List<User> findAll();
}
Test文件下的测试类 MyBatisTest
package com.itheima.test;
import com.itheima.dao.IUserDao;
import com.itheima.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;
/**
* 入门案例
*/
public class MybatisTest {
public static void main(String[] args) throws Exception{
//1.读取配置文件,目的是将配置文件加载
InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
//2.创建SqlSessionFactory工厂
SqlSessionFactoryBuilder sfb = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = sfb.build(in);
//3.使用工厂生产SqlSession对象
SqlSession session = factory.openSession();
//4.使用SqlSession创建Dao接口的代理对象
IUserDao userdao = session.getMapper(IUserDao.class);
//5.使用代理对象执行方法
List<User> users = userdao.findAll();
for (User user : users) {
System.out.println(user);
}
//6.释放资源
session.close();
in.close();
}
}
运行结果
总结
- 如果使用注解,那么将不需要dao接口的映射配置文件,即不需要IUserDao.xml,sql语句写在注解后面括号中的引号内
- mybatis主配置文件SqlMapConfig.xml不能删,因为它是配置数据库的,删了就和数据库连接不上了
- 主配置文件中的mapper配置:resource和xml映射配置文件相应,class和注解相应,二者后面跟的都是全限定类名
- 如
@Select(" select * from user ")
这样,就是注解格式。注解有很多,以后在细写,就不在入门文章中赘述。
- xml这种方式适合大项目使用,如果只是日常小案例,建议用注解。怎么简便怎么来。