14.MyBatis中注解实现CRUD以及其他操作_mybatis 注解获取查询总条数

1.结构图

2.User实体类

package com.itheima.pojo;
 
import java.util.Date;
 
public class User {
    private Integer id;
    private String username;
    private String sex;
    private String address;
    private Date birthday;
 
    public Integer getId() {
        return id;
    }
 
    public void setId(Integer id) {
        this.id = id;
    }
 
    public String getUsername() {
        return username;
    }
 
    public void setUsername(String username) {
        this.username = username;
    }
 
    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;
    }
 
    public Date getBirthday() {
        return birthday;
    }
 
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
 
    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                ", birthday=" + birthday +
                '}';
    }
}

3.IUserDao接口

package com.itheima.dao;
 
import com.itheima.pojo.User;
import org.apache.ibatis.annotations.*;
 
import java.util.List;
 
/*
    Mybatis中针对CRUD一共有四个注解
*   @Select() @Insert() @Update() @Delete()
* */
public interface IUserDao {
    //查询所有
    @Select(value = "select * from user")
    List<User> findUser();
 
    //保存一个
    @Insert("insert into user(username,birthday,address,sex) values (#{username},#{birthday},#{address},#{sex})")
    /*@SelectKey(keyProperty = "id",keyColumn = "id",resultType = Integer.class,before = false,statement = "select last_insert_id()")*/
    int insertUser(User user);
 
    //更新一个
    @Update("update user set username=#{username},address=#{address},birthday=#{birthday},sex=#{sex} where id=#{id}")
    int updateUser(User user);
 
    //删除一个
    @Delete("delete  from user where id = #{id}")
    int deleteUser(Integer id);
 
    //查询根据id
    @Select("select * from user where id = #{id}")
    User findById(Integer id);
 
 
    //模糊查询
    @Select("select * from user where username like #{username}")
    List<User> findByName(String username);
 
    //总条数
    @Select("select count(*) from user")
    int countTotal();
 
}

4.外部数据连接

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/db_mybatis
jdbc.username=root
jdbc.password=123456

5.主配置文件SqlMapConfig.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>
    <!--p配置外部数据库-->
    <properties resource="jdbcConfig.properties"></properties>
    <!--配置别名-->
    <typeAliases>
        <!--自定义别名 实体类所在位置-->
        <package name="com.itheima.pojo"/>
    </typeAliases>
    <!--配置环境-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>
    <!--指定带有接口注解的位置-->
    <mappers>
        <package name="com.itheima.dao"/>
    </mappers>
</configuration>

6.测试类TestAnn

package com.itheima;
 
import com.itheima.dao.IUserDao;
import com.itheima.pojo.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.InputStream;
import java.util.List;
 
public class TestAnn {
    public static void main(String[] args) throws Exception {
        //1.获取字节输入流
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.根据字节输入流构建SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.根据SqlSessionFactory生产一个SqlSession
        SqlSession sqlSession = factory.openSession();
        //4.使用SqlSession获取Dao的代理对象
        IUserDao userDao = sqlSession.getMapper(IUserDao.class);
        //5.执行Dao的方法：查询所有
        List<User> users = userDao.findUser();
        for (User user :users){
            System.out.println(user);
        }
        //6.释放资源..
        sqlSession.close();
        in.close();
    }
}

7.测试类TestCRUD以及其他

package com.itheima;
 
import com.itheima.dao.IUserDao;
import com.itheima.pojo.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 org.junit.After;
import org.junit.Before;
import org.junit.Test;
 
import java.io.InputStream;
import java.util.Date;
import java.util.List;
 
public class TestCRUD {
    private  InputStream in;
    private SqlSessionFactory factory;
    private SqlSession sqlSession;
    private IUserDao userDao;
    //初始化
    @Before
    public void init() throws Exception {
        //1.获取字节输入流
        in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.根据字节输入流构建SqlSessionFactory
        factory = new SqlSessionFactoryBuilder().build(in);
        //3.根据SqlSessionFactory生产一个SqlSession
        sqlSession = factory.openSession();
        //4.使用SqlSession获取Dao的代理对象
        userDao = sqlSession.getMapper(IUserDao.class);
    }
    @After
    public void destroy() throws Exception{
        //6.释放资源..
        sqlSession.commit();
        sqlSession.close();
        in.close();
    }
    //查询所有
    @Test
    public void testFindAll(){
        List<User> users = userDao.findUser();
        for (User user:users){
            System.out.println(user);
        }
    }
    //保存一个
    @Test
    public void testSave(){
        User user = new User();
        user.setUsername("张三");
        user.setSex("男");
        user.setAddress("武汉");
        user.setBirthday(new Date());
        userDao.insertUser(user);
        System.out.println("保存成功");
    }
    //更新一个
    @Test
    public void testUpdate(){
        User user = new User();
        user.setId(1);
        user.setUsername("hhhhhhhhhh");
        user.setSex("男");
        user.setAddress("武汉");
        user.setBirthday(new Date());
        userDao.updateUser(user);
        System.out.println("保存成功");
    }
    //删除一个
    @Test
    public void testDelete(){
       userDao.deleteUser(9);
        System.out.println("删除成功---");
    }
    //查询一个
    @Test
    public void testFindOne(){
        User user = userDao.findById(8);
        System.out.println("查询成功---"+user);
    }
    //模糊查询
    @Test
    public void testFindName(){
        /*多条数据用list*/
        List<User> users = userDao.findByName("%王%");
        for (User user:users){
            System.out.println("模糊查询成功---"+user);
        }
    }
    //根据id查询一个
    @Test
    public void testFindById(){
        User user =  userDao.findById(3);
        System.out.println(user);
    }
    //查询总记录条数
    @Test
    public void testFindTotal(){
        int i = userDao.countTotal();
        System.out.println("总条数为="+i);
    }
 
}

8.依赖pom.xml 

<dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.40</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.mybatis/mybatis -->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
    </dependencies>