Intellij Mybatis连接Mysql数据库

Z时代
2024-01-10
分类：IT

有好一段时间没有学习新东西了，过了个十月一感觉事情还是越早做越好，废话不多说了，说一下用mybatis连接MySQL数据库，上一篇写了jdbc测试，我的数据库表还是原来的。由于从网上查的资料大部分都是eclipse，由于我是做Android开发的，习惯了ide，所以就硬着头皮来了，中间其实遇到过好多问题。

看一下工程结构

先说一下Java代码，dao是查询接口，model是ben和对应的查询语句的xml，我感觉这样有点不好，user.xml放在dao里面比较好，等理解了就知道了，由于我是初学者所以好多东西都不是很理解，后期会给出合理的包的定义

test是我做测试用的

再说一下resources，configuration是配置文件，log4j是日志打印，其他的暂时用不到。

好来看一下代码，我按照建文件的顺序给大家来，

首先需要有一个对象，对象根据数据库建

user.java


package com.fanyafeng.model;
import java.util.Date;
/**
* Author： fanyafeng
* Data： 16/10/11 14:56
* Email: fanyafeng@live.cn
*/
public class User {
private int id;
private String username;
private Date birthday;
private String sex;
private String address;
public int getId() {
return id;
}
public void setId(int 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 + '\'' +
'}';
}
}

iuserdao.java


package com.fanyafeng.dao;
import com.fanyafeng.model.User;
import java.util.List;
/**
* Author： fanyafeng
* Data： 16/10/11 14:55
* Email: fanyafeng@live.cn
*/
public interface IUserDao {
public List<User> queryUserByName(String name);
public User selectUserById(int id);
public void add();
public void del(int id);
public void alter(int id);
}

user.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">
<!--resultType 指定单条记录返回的类型-->
<mapper namespace="com.fanyafeng.dao.IUserDao">
<select id="selectUserById" parameterType="int" resultType="com.fanyafeng.model.User">
select * from user where id = #{id}
</select>
<!--'%${value}' 表示拼接sql串,只能使用value,有可能会引起sql注入的情况-->
<select id="queryUserByName" parameterType="String" resultType="com.fanyafeng.model.User">
SELECT * FROM user WHERE username LIKE #{name}
</select>
<!--INSERT INTO USER (id,username,sex,address) VALUE (null,"陈潇然","女","大学同学")-->
<insert id="add" parameterType="com.fanyafeng.model.User">
insert into user (id,username,birthday,sex,address) values (#{id},#{username},#{birthday},#{sex},#{address})
</insert>
</mapper>

usertest.java


package com.fanyafeng.test;
import com.fanyafeng.model.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.IOException;
import java.io.Reader;
import java.util.Date;
import java.util.List;
/**
* Author： fanyafeng
* Data： 16/10/11 14:58
* Email: fanyafeng@live.cn
*/
public class UserTest {
private static SqlSessionFactory sqlSessionFactory;
private static Reader reader;
static {
try {
reader = Resources.getResourceAsReader("Configuration.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
SqlSession sqlSession = sqlSessionFactory.openSession();
try {
// User user = (User) sqlSession.selectOne("com.fanyafeng.dao.IUserDao.selectUserById", 2);
// System.out.println(user.getAddress() + user.getSex() + user.getBirthday());
// System.out.println(user.getId() + user.getUsername());
//
//
List<User> userList = sqlSession.selectList("com.fanyafeng.dao.IUserDao.queryUserByName", "%李宁%");
for (int i = 0; i < userList.size(); i++) {
System.out.println(userList.get(i).toString());
}
User user = new User();
user.setId(100);
user.setBirthday(new Date());
user.setUsername("李宁");
user.setSex("女");
user.setAddress("家里蹲");
int isAdd = sqlSession.insert("com.fanyafeng.dao.IUserDao.add", user);
sqlSession.commit();//不要忘记
} finally {
sqlSession.close();
}
}
}

configration.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>
<!--如果在mapper中进行配置了,此处可以省略配置-->
<!--<typeAliases>-->
<!--<typeAlias alias="User" type="com.fanyafeng.model.User"/>-->
<!--</typeAliases>-->
<!-- 和spring整合后 environments配置将废除-->
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理-->
<transactionManager type="JDBC"/>
<!-- 数据库连接池-->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8"/>
<property name="username" value="root"/>
<property name="password" value=""/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/fanyafeng/model/User.xml"/>
</mappers>
</configuration>

log4j的话大家根据自己的爱好添加就好了，代码中注释写的很详细了，我就不细讲了，这里有个地方让我很憋屈，问了个大神才知道咋回事，截图中有target目录吧，这是编译好文件的存放位置，可是，问题来了，java文件给我编译好放在哪里了，可是非resource得xml文件没有给我放进去，丢出来了一个异常，查了好多资料答非所问，然后是这样解决的

看一下pom.xml文件，我更改后的，加了build标签中了


<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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.fanyafeng</groupId>
<artifactId>mybatisdemo</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>mybatisdemo Maven Webapp</name>
<url>http://maven.apache.org</url>
<build>
<finalName>mybatisdemo</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>**/*.xml</include>
<include>**/*.properties</include>
</includes>
</resource>
<resource>
<directory>src/main/java</directory>
<includes>
<include>**/*.xml</include>
</includes>
</resource>
</resources>
</build>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>3.8.1</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.8</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-log4j12 -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.21</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.slf4j/slf4j-api -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.21</version>
</dependency>
<!-- https://mvnrepository.com/artifact/log4j/log4j -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-core -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-core</artifactId>
<version>2.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-api -->
<dependency>
<groupId>org.apache.logging.log4j</groupId>
<artifactId>log4j-api</artifactId>
<version>2.5</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.javassist/javassist -->
<dependency>
<groupId>org.javassist</groupId>
<artifactId>javassist</artifactId>
<version>3.18.1-GA</version>
</dependency>
<!-- https://mvnrepository.com/artifact/commons-logging/commons-logging -->
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
</dependency>
<!-- https://mvnrepository.com/artifact/cglib/cglib -->
<dependency>
<groupId>cglib</groupId>
<artifactId>cglib</artifactId>
<version>2.2.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/asm/asm -->
<dependency>
<groupId>asm</groupId>
<artifactId>asm</artifactId>
<version>3.3.1</version>
</dependency>
</dependencies>
</project>