Mybatis基础方式的增删改查CRUD:

mybatis规定：
输入参数parameterType 和 输出参数resultType ，在形式上都只能有一个

输入参数:
如果是简单类型（8个基本类型+String） 是可以使用任何占位符,#{xxxx}
如果是对象类型，则必须是对象的属性 #{属性名}

输出参数：
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，
即 resultType=“org.lanqiao.entity.Student”

注意事项：

1. 如果使用的 事务方式为 jdbc,则需要 手工commit提交，即session.commit();
2. 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);

demo:

Test.java:

package org.lanqiao.entity;

import java.io.IOException;
import java.io.Reader;
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 Test {
	//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的第二参数 指定数据库环境
				SqlSessionFactory sessionFacotry = new SqlSessionFactoryBuilder().build(reader,"development") ;
				SqlSession session = sessionFacotry.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的第二参数 指定数据库环境
					SqlSessionFactory sessionFacotry = new SqlSessionFactoryBuilder().build(reader,"development") ;
					SqlSession session = sessionFacotry.openSession() ;
					
					
					
					String statement = "org.lanqiao.entity.studentMapper."+"queryAllStudents";
					List<Student> students = session.selectList(statement) ;
					System.out.println(students);
					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的第二参数 指定数据库环境
					SqlSessionFactory sessionFacotry = new SqlSessionFactoryBuilder().build(reader,"development") ;
					SqlSession session = sessionFacotry.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
					
					System.out.println("增加"+count+"个学生");
					session.close();
		}
 		
 		
 		 //删除学生
 		public static void delteStudentByStuno() throws IOException {
 			//Connection -  SqlSession操作MyBatis
					//conf.xml - > reader
					Reader reader = Resources.getResourceAsReader("conf.xml") ;
					//reader  ->SqlSession
					//可以通过build的第二参数 指定数据库环境
					SqlSessionFactory sessionFacotry = new SqlSessionFactoryBuilder().build(reader,"development") ;
					SqlSession session = sessionFacotry.openSession() ;
					
					String statement = "org.lanqiao.entity.studentMapper."+"deleteStudentByStuno";
					
					int count = session.delete(statement,3) ;
					
					session.commit(); //提交事务
					
					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的第二参数 指定数据库环境
					SqlSessionFactory sessionFacotry = new SqlSessionFactoryBuilder().build(reader,"development") ;
					SqlSession session = sessionFacotry.openSession() ;
					
					String statement = "org.lanqiao.entity.studentMapper."+"updateStudentByStuno";
					//修改的参数
					Student student = new Student();
					//修改哪个人，where stuno =2 
					student.setStuNo(2);
					//修改成什么样子？
					student.setStuName("lxs");
					student.setStuAge(44);
					student.setGraName("s2");
					//执行
					int count = session.update(statement,student) ;
					
					session.commit(); //提交事务
					
					System.out.println("修改"+count+"个学生");
					session.close();
		}
	
	
	public static void main(String[] args) throws IOException {
		queryAllStudents();
//		 addStudent() ;
//		delteStudentByStuno();
		updateStudentByStuno();
		queryAllStudents();
	}
}

Student.java

package org.lanqiao.entity;

public class Student {
	private int stuNo ;
	private String stuName ;
	private int stuAge ;
	private String graName ;
	public Student() {
	}
	
	
	public Student(int stuNo, String stuName, int stuAge, String graName) {
		this.stuNo = stuNo;
		this.stuName = stuName;
		this.stuAge = stuAge;
		this.graName = 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;
	} 
	
	@Override
	public String toString() {
		return this.stuNo+"-"+this.stuName+"-"+this.stuAge+"-"+this.graName;
	}
	
}

studentMapper.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">

<!-- namespace:该mapper.xml映射文件的 唯一标识 -->
<mapper namespace="org.lanqiao.entity.studentMapper">
	<!--  后续通过  namespace.id-->
	<!--parameterType:输入参数的类型
	resultType：查询返回结果值的类型  ，返回类型  -->
	<select id="queryStudentByStuno" parameterType="int"  resultType="org.lanqiao.entity.Student" >
			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>

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

conf.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>
	<!-- 通过environments的default值 和  environment的 id 来指定 MyBatis运行时的数据库环境-->
	<environments default="development">
		<!-- 开发环境（自己的计算机） -->
		<environment id="development">
		
		
			<!-- 事务提交方式：
				JDBC:利用JDBC方式处理事务（commit  rollback  close）
				MANAGED：将事务交由 其他组件去托管（spring ,jobss）,默认 会关闭连接。
			
			<transactionManager type="MANAGED"/>
				<property name="closeConnection" value="false"/>
			 -->
			   <transactionManager type="JDBC" />
				<!-- 数据源类型：
						UNPOOLED:传统的JDBC模式（每次访问数据库，均需要 打开、关闭等数据库操作，但是 打开、关闭数据库是比较消耗性能的）
						POOLED：使用数据库连接池
						JNDI：从tomcat中获取一个内置的数据库连接池 （数据库连接池-数据源  ）
				 -->
				 
				<dataSource type="POOLED">
				
				
					<!-- 配置数据库信息 -->
					<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>
		
		<!-- 真正的项目应该在   发布的那台计算机上运行 -->
		<environment id="shishi">
			<transactionManager type="JDBC"/>
				<dataSource type="POOLED">
				<!-- 配置数据库信息 -->
				<property name="driver" value="oracle.jdbc.OracleDriver"/>
				<property name="url" value="jdbc:oracle:thin:@192.168.1.183:1521:ORCL"/>
				<property name="username" value="scott"/>
				<property name="password" value="tiger"/>
			</dataSource>
		</environment>
		
		
		<!--  -->
		<environment id="test">
			<transactionManager type="JDBC"/>
				<dataSource type="POOLED">
				<!-- 配置数据库信息 -->
				<property name="driver" value="oracle.jdbc.OracleDriver"/>
				<property name="url" value="jdbc:oracle:thin:@192.168.1.111:1521:ORCL"/>
				<property name="username" value="scott"/>
				<property name="password" value="tiger"/>
			</dataSource>
		</environment>
	</environments>
	
	
	
	<mappers>
		<!-- 加载映射文件 -->
		<mapper resource="org/lanqiao/entity/studentMapper.xml"/>
	</mappers>
</configuration>