mybatis入门

本文详细介绍了如何使用Maven构建项目,并整合MyBatis框架实现数据库操作,包括创建数据库表、配置POM文件、编写mybatis-config.xml、User类及XML映射文件等关键步骤。

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新建maven工程




数据库用mysql5

SQL:

CREATE TABLE user
(
  id int(11) NOT NULL AUTO_INCREMENT,
  username varchar(20) NOT NULL,
  password varchar(20) NOT NULL,
  PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
INSERT INTO user VALUES ('1', 'admin', 'admin');

pom文件

<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>mybatis</groupId>
	<artifactId>mybatis</artifactId>
	<version>0.0.1-SNAPSHOT</version>

	<dependencies>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId> mysql-connector-java</artifactId>
			<version>5.0.5</version>
		</dependency>

		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.2.1</version>
		</dependency>

		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis-spring</artifactId>
			<version>1.2.0</version>
		</dependency>
		
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.8.1</version>
			<scope>test</scope>
		</dependency>
	</dependencies>
</project>


mybatis-config.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>
	<typeAliases>
		<typeAlias alias="User" type="model.User" />
	</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://127.0.0.1:3306/mybatis" />
				<property name="username" value="root" />
				<property name="password" value="root123" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<mapper resource="model/User.xml" />
		<mapper resource="dao/User.xml" />
	</mappers>
</configuration>



User.java:


package model;

public class User {
	private int id;
	private String username;
	private String password;
	public User(){
		
	}
	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 String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String toString(){
		 return "User [id = "+ id +" , username = "+ username +"]" + " , password = "+ password;
	}
}

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">
<mapper namespace="model.User">
	<select id="selectUserByID" parameterType="int" resultType="User">
		SELECT * FROM user WHERE id = #{id}
	</select>
	<insert id="insertUser" parameterType="model.User" flushCache="true">
		INSERT INTO user (id,username,password) VALUES
		(#{id},#{username},#{password})
	</insert>
	<update id="updateUser" parameterType="model.User">
		UPDATE user SET
		password=#{password} WHERE id=#{id}
	</update>
	<delete id="deleteUser" parameterType="int">
		DELETE FROM user WHERE
		id=#{userId}
	</delete>
</mapper>

测试代码:


	private static SqlSessionFactory sqlSessionFactory;
	private static Reader reader;
	static {
		try {
			reader = Resources.getResourceAsReader("mybatis-config.xml");
			sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static SqlSessionFactory getSession() {
		return sqlSessionFactory;
	}

	public void testUser1() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			User user = (User) session.selectOne("model.User.selectUserByID", 1);
			System.out.println(user.getUsername());
			System.out.println(user.getPassword());
		} finally {
			session.close();
		}
	}

接口方式:


package dao;

import model.User;

public interface IUserOperation {
	public User selectUserByID(int id);
	public User selectUser(User user);
	public void insertUser(User user);
	public void updateUser(User user);
	public void deleteUser(int userId);
}

<?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">
<mapper namespace="dao.IUserOperation">
	<select id="selectUserByID" parameterType="int" resultType="User">
        SELECT * FROM user WHERE id = #{id}
    </select>
    <insert id="insertUser" parameterType="model.User" flushCache="true">
		INSERT INTO user (id,username,password) VALUES
		(#{id},#{username},#{password})
	</insert>
	<update id="updateUser" parameterType="model.User">
		UPDATE user SET password=#{password} WHERE id=#{id}
	</update>
	<delete id="deleteUser" parameterType="int">
		DELETE FROM user WHERE id=#{userId}
	</delete>
</mapper>

测试代码:


	public void testUser2() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			IUserOperation userOperation = session.getMapper(IUserOperation.class);
			User user = userOperation.selectUserByID(1);
			System.out.println(user.getUsername());
			System.out.println(user.getPassword());
		} finally {
			session.close();
		}
	}

增删改查测试代码:


	public void testUser1Insert() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			User user = new User();
			user.setId(2);
			user.setUsername("user2");
			user.setPassword("pass2");
			session.insert("model.User.insertUser", user);
			session.commit();
		} finally {
			session.close();
		}
	}

	public void testUser1Update() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			User user = new User();
			user.setId(2);
			user.setUsername("user02");
			user.setPassword("pass02");
			session.update("model.User.updateUser", user);
			session.commit();
		} finally {
			session.close();
		}
	}

	public void testUser1Delete() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			session.delete("model.User.deleteUser", 2);
			session.commit();
		} finally {
			session.close();
		}
	}

	public void testUser2Insert() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			IUserOperation userOperation = session.getMapper(IUserOperation.class);
			User user = new User();
			user.setId(2);
			user.setUsername("user2");
			user.setPassword("pass2");
			userOperation.insertUser(user);
			session.commit();
		} finally {
			session.close();
		}
	}

	public void testUser2Update() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			IUserOperation userOperation = session.getMapper(IUserOperation.class);
			User user = new User();
			user.setId(2);
			user.setUsername("user02");
			user.setPassword("pass02");
			userOperation.updateUser(user);
			session.commit();
		} finally {
			session.close();
		}
	}

	public void testUser2Delete() {
		SqlSession session = sqlSessionFactory.openSession();
		try {
			IUserOperation userOperation = session.getMapper(IUserOperation.class);
			userOperation.deleteUser(2);
			session.commit();
		} finally {
			session.close();
		}
	}


内容概要:本文探讨了在MATLAB/SimuLink环境中进行三相STATCOM(静态同步补偿器)无功补偿的技术方法及其仿真过程。首先介绍了STATCOM作为无功功率补偿装置的工作原理,即通过调节交流电压的幅值和相位来实现对无功功率的有效管理。接着详细描述了在MATLAB/SimuLink平台下构建三相STATCOM仿真模型的具体步骤,包括创建新模型、添加电源和负载、搭建主电路、加入控制模块以及完成整个电路的连接。然后阐述了如何通过对STATCOM输出电压和电流的精确调控达到无功补偿的目的,并展示了具体的仿真结果分析方法,如读取仿真数据、提取关键参数、绘制无功功率变化曲线等。最后指出,这种技术可以显著提升电力系统的稳定性与电能质量,展望了STATCOM在未来的发展潜力。 适合人群:电气工程专业学生、从事电力系统相关工作的技术人员、希望深入了解无功补偿技术的研究人员。 使用场景及目标:适用于想要掌握MATLAB/SimuLink软件操作技能的人群,特别是那些专注于电力电子领域的从业者;旨在帮助他们学会建立复杂的电力系统仿真模型,以便更好地理解STATCOM的工作机制,进而优化实际项目中的无功补偿方案。 其他说明:文中提供的实例代码可以帮助读者直观地了解如何从零开始构建一个完整的三相STATCOM仿真环境,并通过图形化的方式展示无功补偿的效果,便于进一步的学习与研究。
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