mybatis基础方式的增删改查CRUD

àì夳堔傛蜴生んèń 2024-03-17 20:32 95阅读 0赞

## mybatis基础方式的增删改查CRUD ##

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lombok.jar 注解  
一、Lombok构造方法注解的使用方法 Lombok提供了三个构造方法注解:

@NoArgsConstructor、@AllArgsConstructor和@RequiredArgsConstructor。

分别对应着`无参构造方法、全参构造方法和有参构造方法`(根据类的成员变量自动生成参数)。

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> 一、 基础方式的增删改查CRUD：  
> mybatis约定：  
> 输入参数 parameterType 和 输出参数 resultType 在形式上 都只能有一个

> 如果输入，输出参数 : 是 简单类型 （8个基本类型 + String） , 则可以使用任何占位符。\#\{xxxxx\}  
> 如果是对象类型，则必须是对象的属性、\#\{属性名\}

> 如果返回值类型是一个 对象 （如Student），则无论返回一个，还是多个，  
> 在resultType都写成 org.lanqiao.entity.Student  
> 即 resultType=“org.lanqiao.entity.Student”

> 注意事项:  
> a 如果使用的 事务方式为 JDBC，则需要手动commit提交，即session.commit();  
> b 所有的标签`<select> <update>` <>等，都必须有SQL语句，但是SQL参数值可选  
> select \* from student where stuno = \#\{xx\}  
> sql有参数: session.insert(statement, 参数值 );  
> sql没参数: session.insert(statement);

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**Student.java**

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package org.lanqiao.entity;
    
    import lombok.AllArgsConstructor;
    import lombok.Getter;
    import lombok.NoArgsConstructor;
    import lombok.RequiredArgsConstructor;
    import lombok.Setter;
    import lombok.ToString;
    
    @Getter
    @Setter
    @NoArgsConstructor
    @AllArgsConstructor
    public class Student {
        
    	private int stuNo;
    	private String stuName;
    	private int stuAge;
    	private String graName;
    
    	public int getStuNo() {
        
    		return stuNo;
    	}
    
    	public void setStuNo(int stuNo) {
        
    		this.stuNo = stuNo;
    	}
    
    	public String getStuName() {
        
    		return stuName;
    	}
    
    	public void setStuName(String stuName) {
        
    		this.stuName = stuName;
    	}
    
    	public int getStuAge() {
        
    		return stuAge;
    	}
    
    	public void setStuAge(int stuAge) {
        
    		this.stuAge = stuAge;
    	}
    
    	public String getGraName() {
        
    		return graName;
    	}
    
    	public void setGraName(String graName) {
        
    		this.graName = graName;
    	}
    
    	public Student() {
        
    	}
    
    	public Student(int stuNo, String stuName, int stuAge, String graName) {
        
    		super();
    		this.stuNo = stuNo;
    		this.stuName = stuName;
    		this.stuAge = stuAge;
    		this.graName = graName;
    	}
    
    	@Override
    	public String toString() {
        
    		return "Student [stuNo=" + stuNo + ", stuName=" + stuName + ", stuAge=" + stuAge + ", graName=" + graName + "]";
    	}
    
    }

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**创建表 student**

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create table student(stuno　NUMBER, stuname VARCHAR2(20), stuage NUMBER, graname VARCHAR2(20) );
    alter table student add constraint student primary key (stuno);
    
    INSERT into student VALUES(1, 'zs', 23, 'g1');
    INSERT into student VALUES(2, 'ls', 24, 'g1'); 
    commit;

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**conf.xml**

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<?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>
    	
    	<environments default="development">
    		
    		<environment id="development">
    		
    			
    			<transactionManager type="JDBC" />
    			
    			
    			<dataSource type="POOLED">
    				
    				<property name="driver" value="oracle.jdbc.OracleDriver" />
    				<property name="url"
    					value="jdbc:oracle:thin:@127.0.0.1:1521:ORCL" />
    				<property name="username" value="scott" />
    				<property name="password" value="tiger" />
    			</dataSource>
    		</environment>
    
    		
    		<environment id="shishi">
    			<transactionManager type="JDBC" />
    			<dataSource type="POOLED">
    				
    				<property name="driver" value="oracle.jdbc.OracleDriver" />
    				<property name="url"
    					value="jdbc:oracle:thin:@127.0.0.2:1521:ORCL" />
    				<property name="username" value="scott" />
    				<property name="password" value="tiger" />
    			</dataSource>
    		</environment>
    
    		
    		<environment id="test">
    			<transactionManager type="JDBC" />
    			<dataSource type="POOLED">
    				
    				<property name="driver" value="oracle.jdbc.OracleDriver" />
    				<property name="url"
    					value="jdbc:oracle:thin:@127.0.0.3:1521:ORCL" />
    				<property name="username" value="scott" />
    				<property name="password" value="tiger" />
    			</dataSource>
    		</environment>
    
    	</environments>
    	<mappers>
    		
    		<mapper resource="org/lanqiao/entity/studentMapper.xml" />
    	</mappers>
    </configuration>

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**studentMapper.xml**

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<?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="org.lanqiao.entity.studentMapper">
    
    	
    	
    	
    	<select id="queryStudentByStuno" resultType="org.lanqiao.entity.Student" parameterType="int">
    		select * from student where stuno = #{stuno}
    	</select>
    	
    	<insert id="addStudent" parameterType="org.lanqiao.entity.Student" >
    		 insert into student(stuno, stuname, stuage, graname) values(#{stuNo},#{stuName},#{stuAge},#{graName} )
    	</insert>
    	
    	<update id="updateStudentByStuno" parameterType="org.lanqiao.entity.Student">
    		update student set stuname=#{stuName}, stuage=#{stuAge}, graname=#{graName} where stuno=#{stuNo} 
    	</update>
    	
    	<delete id="deleteStudentByStuno" parameterType="int">
    		delete from student where stuno = #{stuno}
    	</delete>
    	
    	<select id="queryAllStudents" resultType="org.lanqiao.entity.Student">
    		select * from student
    	</select>
    
    </mapper>

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**TestMybatis.java**

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package org.lanqiao.entity;
    
    import java.io.IOException;
    import java.io.Reader;
    import java.util.Iterator;
    import java.util.List;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    public class TestMybatis {
        
    
    	// 查询单个学生
    	public static void queryStudentByStuno() throws IOException {
        
    		// Connection - SqlSession操作MyBatis
    		// conf.xml - > reader
    		Reader reader = Resources.getResourceAsReader("conf.xml");
    		// reader -> SqlSession
    
    		// 可以通过build的第二个参数 指定数据库环境
    		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader, "development");
    		// SqlSessionFactory connection
    		// 工厂模式
    		SqlSession session = sessionFactory.openSession();
    		String statement = "org.lanqiao.entity.studentMapper.queryStudentByStuno";
    		Student student = session.selectOne(statement, 1);
    		System.out.println(student);
    		session.close();
    	}
    
    	// 查询全部学生
    	public static void queryAllStudents() throws IOException {
        
    		// Connection - SqlSession操作MyBatis
    		// conf.xml - > reader
    		Reader reader = Resources.getResourceAsReader("conf.xml");
    		// reader -> SqlSession
    
    		// 可以通过build的第二个参数 指定数据库环境
    		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader, "development");
    		// SqlSessionFactory connection
    		// 工厂模式
    		SqlSession session = sessionFactory.openSession();
    
    		String statement = "org.lanqiao.entity.studentMapper." + "queryAllStudents";
    		List<Student> students = session.selectList(statement);
    		for (Object student : students) {
        
    			System.out.println("student=" + student);
    		}
    		session.close();
    	}
    
    	// 增加学生
    	public static void addStudent() throws IOException {
        
    		// Connection - SqlSession操作MyBatis
    		// conf.xml - > reader
    		Reader reader = Resources.getResourceAsReader("conf.xml");
    		// reader -> SqlSession
    
    		// 可以通过build的第二个参数 指定数据库环境
    		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader, "development");
    		// SqlSessionFactory connection
    		// 工厂模式
    		SqlSession session = sessionFactory.openSession();
    
    		String statement = "org.lanqiao.entity.studentMapper." + "addStudent";
    		Student student = new Student(3, "ww", 25, "s1");
    		int count = session.insert(statement, student); // statement:指定执行的SQL, student: SQL中需要的参数(???)
    		session.commit(); // 提交事务 JDBC 手动提交
    
    		System.out.println("增加" + count + "个学生");
    		session.close();
    	}
    
    	// 删除学生
    	public static void deleteStudentByStuno() throws IOException {
        
    		// Connection - SqlSession操作MyBatis
    		// conf.xml - > reader
    		Reader reader = Resources.getResourceAsReader("conf.xml");
    		// reader -> SqlSession
    
    		// 可以通过build的第二个参数 指定数据库环境
    		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader, "development");
    		// SqlSessionFactory connection
    		// 工厂模式
    		SqlSession session = sessionFactory.openSession();
    
    		String statement = "org.lanqiao.entity.studentMapper." + "deleteStudentByStuno";
    		int count = session.delete(statement, 3);
    		session.commit(); // 提交事务 JDBC 手动提交
    
    		System.out.println("删除" + count + "个学生");
    		session.close();
    	}
    
    	// 修改学生
    	public static void updateStudentByStuno() throws IOException {
        
    		// Connection - SqlSession操作MyBatis
    		// conf.xml - > reader
    		Reader reader = Resources.getResourceAsReader("conf.xml");
    		// reader -> SqlSession
    
    		// 可以通过build的第二个参数 指定数据库环境
    		SqlSessionFactory sessionFactory = new SqlSessionFactoryBuilder().build(reader, "development");
    		// SqlSessionFactory connection
    		// 工厂模式
    		SqlSession session = sessionFactory.openSession();
    
    		String statement = "org.lanqiao.entity.studentMapper." + "updateStudentByStuno";
    		// 修改的参数
    		Student student = new Student();
    		// 修改那个人， where stuno = ?
    		student.setStuNo(2);
    		// 修改成什么样子?
    		student.setStuName("lxs");
    		student.setStuAge(45);
    		student.setGraName("s2");
    		// 执行
    		int count = session.update(statement, student);
    
    		session.commit(); // 提交事务 JDBC 手动提交
    
    		System.out.println("修改" + count + "个学生");
    		session.close();
    	}
    
    	public static void main(String[] args) throws IOException {
        
    
    //		queryStudentByStuno();
    
    		queryAllStudents();
    
    //		addStudent();
    //		deleteStudentByStuno();
    		updateStudentByStuno();
    
    		queryAllStudents();
    
    	}
    
    }

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