Mybatis框架的模糊查询（多种写法）删除添加

Posted 2020-08-24 葉子。

　　　　　　学习Mybatis这么多天，那么我给大家分享一下我的学习成果。从最基础的开始配置。

一、创建一个web项目，看一下项目架构

二、说道项目就会想到需要什么jar

　　 

三、就是准备大配置链接Orcl数据库

<?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>
     
     <!-- 别名的定制 -->
     <typeAliases>
        <!-- 按类型名定制别名  -->
        <!--   <typeAlias type="cn.happy.entity.Student" alias="Student"/> -->
        
        <!-- 拿当前指定包下的简单类名作为别名  -->
        <package name="cn.happy.entity"/>
     </typeAliases>
 

    <environments default="development">
        <environment id="development">
            <!-- 使用jdbc的事务 -->
            <transactionManager type="JDBC" />
            <!-- 使用自带的连接池 -->
            <dataSource type="POOLED">
                <property name="driver" value="oracle.jdbc.driver.OracleDriver"/>
                  <property name="url" value="jdbc:oracle:thin:@localhost:1521:orcl"/>
                <property name="username" value="T2" />
                <property name="password" value="T2" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="cn/happy/dao/StudentDAO.xml" />
    </mappers>
</configuration>

四、准备小配置

<?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="cn.happy.dao.IStudentDAO">
//增删改
</mapper>

 

五、准备工具类

package cn.happy.util;

import java.io.IOException;
import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

/**
 * 工具类
 * @author Happy
 *
 */
public class MybatisUtil {
    private static String config="mybatis-config.xml";
    static Reader reader;
    static{
        try {
            reader= Resources.getResourceAsReader(config);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    private static SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(reader);
    //提供一个可以获取到session的方法
    public static SqlSession getSession() throws IOException{
        
        System.out.println("22222"+factory);
        //弊病，就是工厂是
           // 1.1 openSession到底做了什么
           SqlSession session = factory.openSession();
           System.out.println("3333");
            return session;
    }
}

 

 

六、准备实体类

package cn.happy.entity;

import java.util.Date;

/**
 * 学生实体类
 * @author Happy
 *
 */
public class Student {
  private Integer stuno;
  private String stuname;
  private Integer stuage;
  private Date studate;
  
  
public String toString() {
    return "Student [stuno=" + stuno + ", stuname=" + stuname + ", stuage="
            + stuage + ", studate=" + studate + "]";
}
public Integer getStuno() {
    return stuno;
}
public void setStuno(Integer stuno) {
    this.stuno = stuno;
}
public String getStuname() {
    return stuname;
}
public void setStuname(String stuname) {
    this.stuname = stuname;
}
public Integer getStuage() {
    return stuage;
}
public void setStuage(Integer stuage) {
    this.stuage = stuage;
}
public Date getStudate() {
    return studate;
}
public void setStudate(Date studate) {
    this.studate = studate;
}
  
}

七、下面是具体的代码增删改查前面是公用的

（一）下面实现查看所有

　　1在接口定义方法

 //查询所有记录
   public List<Student> findAll() throws IOException;

　　2在配置中=======>由于动态加载所以不需要实现类

  <!-- 查询所有 -->
    <select id="findAll" resultType="Student">
      select * from student
    </select>

   3测试类中

IStudentDAO dao;
    @Before
    public void initData() throws IOException{
        SqlSession session = MybatisUtil.getSession();
        //动态踢出实现类
        //首先要改StudentDAO.xml改成<mapper namespace="cn.happy.dao.IStudentDAO">
        dao=session.getMapper(IStudentDAO.class);
    }
/**
     * selectALl学生
     * @throws IOException
     */
    
    @Test
    public void findAll() throws IOException{
        List<Student> list = dao.findAll();
        for (Student student : list) {
            System.out.println(student.getStuname());
        }
        
    }

（二）下面是添加

　　1在接口定义方法

//添加
   public int addStu(Student stu) throws IOException;

 

　　2在配置中=======>由于动态加载所以不需要实现类

<insert id="insertStudent" parameterType="Student" >
        insert into student(stuname,stuage,studate) values(#{stuname},#{stuage},#{studate})
        
     <!-- sqlserver 和mysql 只有自自增  自增时机和insert时机： 先insert返回自增值
     
         Oracle先产生一个自增值，然后再执行insert
      -->
      <selectKey keyProperty="stuno" resultType="int">
      <!-- Mysql的 -->
           select @@identity
           <!-- orcl的 -->
           select sql_num.currval from dual
      </selectKey>

    </insert>

 

　　3测试类中

@Test
    public void testAdd() throws IOException{
        Student stu=new Student();
        stu.setStuname("Y2161好人");
        stu.setStuage(21);
        stu.setStudate(new Date());
        
        System.out.println("添加前======="+stu);
        
        IStudentDAO dao=new StudentDAOImpl();
        dao.addStu(stu);
        
        System.out.println("添加后======="+stu);
        
    }

 

（二）下面是删除

　　1在接口定义方法

 //删除
   public int delStu(int id) throws IOException;

 

　　2在配置中=======>由于动态加载所以不需要实现类

<!--删除学生  -->
    
    <delete id="delStudent">
       delete from student where stuno=#{xxx}<!-- #{xxx}随便写，起到一个占位的作用 -->
    </delete>

 

　　3测试类中

/**
     * 删除学生
     * @throws IOException
     */
    
    @Test
    public void delStudent() throws IOException{
        dao.delStu(2);
        System.out.println("ok");
    }
    

 

（二）下面是模糊查询

　　1在接口定义方法

  //按照学生姓名查询学生集合（一个是实体一个是字符串其实都可以）
   public List<Student> findStudntByName(Student stu) throws IOException;
   public List<Student> findStudntByName(String stuname) throws IOException;

 

　　2在配置中=======>由于动态加载所以不需要实现类

 <!--模糊查询  mysql的数据库 -->
    <select id="findStudentByName"  resultType="Student">
     <!--  select * from student where  stuname like  concat(\'%\',#{stuname},\'%\') -->
     select * from student where  stuname like \'%${value}%\'
    </select>  
    

 

　　3测试类中

/**
     * 模糊查询
     * @throws IOException
     */
    
    @Test
    public void findStudentByName() throws IOException{
        
        /*Student stu=new Student();
        stu.setStuname("人");*/
        List<Student> list = dao.findStudntByName("人");
        for (Student student : list) {
            System.out.println(student.getStuname());
        }
        
    }