1-----Mybatis

没有mybatis

建表

查询

import java.sql.*;

public class DatabaseTest {

    public static void main(String[] args) throws SQLException, ClassNotFoundException {

        Class.forName("com.mysql.cj.jdbc.Driver");
        Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8", "root", "123456");
        Statement statement = conn.createStatement();
        String sql = "select * from user where id = ?";
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.setInt(1, 2);
        ResultSet resultSet = preparedStatement.executeQuery();
//        ResultSet resultSet = statement.executeQuery(sql);
        while (resultSet.next()){
            System.out.println(resultSet.getInt(1));
            System.out.println(resultSet.getString(2));
            System.out.println(resultSet.getString(3));
        }
    }
}

直接给你整懵！

statement与preparedment

个人总结：就是一个端茶送水的店小二。。。将sql语句提交给mysql；并将结果集拿回来。

preparedment是比较高级的店小二，会预编译，而且可以自定义查询值，不像statement每次sql语句都得拼接。

快就完事了preparedment

反正很复杂。

mybatis

简介

一款优秀的持久层框架。----------------------------就是数据库
避免几乎所有的JDBC代码和手动设置参数以及获取结果集的过程------------------------------就是全自动呗，不用再自己配statement和preparedment
mybatis可以使用简单的XML或者注解来配置映射原生信息，将接口和Java的实力类相互映射。---------------------------------------数据库中有一个表叫作user，那么java中有一个类叫作user，字段间都相互对应。
以前叫作ibatis
现在再github上也有

持久化

数据可以保持很久，就是保存在磁盘中呗。

持久层

完成持久化工作的代码块------->dao(data access object) 数据访问对象

为什么需要mybatis

帮助存数据、取数据
传统太繁琐
半自动的ORM框架(Object Relationship Mapping)----->对象关系映射

优点：简单、灵活、解除sql语句与程序代码的耦合

简单的mybatis程序

mybatis的执行流程

实体类-----Lombok插件有问题，导不进去

package com.sicheng.entity;


public class User {

    private int id;
    private String name;
    private String pwd;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = pwd;
    }

    public User() {
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

查找类---也就是dao类

就是通过各种姿势查找访问数据库的类

例如：通过主键查找、名字查找、、、、、

package com.sicheng.dao;

import com.sicheng.entity.User;

import java.util.List;

public interface UserMapper {

    List<User> selectUser();
}

Mybatis的配置文件

应该看的懂吧

<?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>
    <!-- 这里写配置内容 -->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/test?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false&amp;serverTimezone=GMT%2B8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <mapper resource="com/sicheng/dao/userMapper.xml"/>
    </mappers>
</configuration>

与dao类相互映射的，mapper文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>
</mapper>

MybatisUtils

用于生产session

package com.sicheng.utils;

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.IOException;
import java.io.InputStream;

public class MybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;

    static{
        try {
            String resource = "mybatis-config.xml";
            InputStream inputStream = null;
            inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static SqlSession getSession(){
        return sqlSessionFactory.openSession();
    }
}

Test

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }
}

注意事项

Mapper文件当中，一定要写namespace，指明这是哪个dao类的映射文件
mapper文件中 id 一定是那个dao类的方法。
UseMapper类和 userMapper配置文件的名字必须保持也一样的哦！！！！！！

补充知识

xml中的 & 是个啥？

xml当中不能显示的符号以及如何进行转义

<	<	小于号
&gt	>	大于号
&amp	&	和
&apos	'	单引号
&quot	"	双引号

第二种方法：

<![CDATA[
   内部的所有内容都会被解析器忽略
]]>

数据库连接中

jdbc:mysql://localhost:3306/test?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false&amp;serverTimezone=GMT%2B8

要写时间区间的，保证安全性？

Resources类

Resources 类为从类路径中加载资源，提供了易于使用的方法。

所以才在加载时，直接使用mybatis-config.xml这个路径名

Resources类的常用情况

从类路径下加载SQL Map配置文件
从类路径加载DAO Manager配置文件
从类路径机在各种.properties文件

Resources类加载一个资源的方式

对于简单的只读文本数据，加载为Reader
对于简单的只读二进制或者文本数据，加载为Stream；
对于读写二进制或文本文件，加载为File.
对于只读的配置文件，加载为Properties
对于只读的通用资源，加载为URL

根据加载方式不同，加载资源的方法如下

Reader getResoutceAsReader(String resource)

Stream getResourceAsStream(String resource)

File getResourceAsFile(String resource)

Properties getResourceAsProperties(String resource);

Url getResourceAsUrl(String resource)

继续各种操作吧

查询

通过主键ID查询

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;

import java.util.List;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

//    //通过name、pwd查
//    List<User> selectUserByNameAndPwd(String name, String pwd);
//
//    //key模糊查询
//    List<User> selectUserByLikeKey(String key);
}

mapper文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>
</mapper>

注意一下：

当只有一个，参数的时候，就都可以不用写；
接入，参数有两个，那写不写都会错的。

上面必错！！！！！

Test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }
}

通过name属性查询

主要是想测试下，当parameterType是复杂类型的，即对象的时候，不写会不会报错

发现并没有什么问题！！！！

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;

import java.util.List;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>
</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }
}

通过根据密码、名字查询

这下传入两种参数，怎么办呢？

第一种方法

@Param(“mapper文件需要调用的名字”)

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);

    //通过name、pwd值进行查询
    List<User> selectUserByNameAndPwd(@Param("name") String name, @Param("pwd") String pwd);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>

    <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User">
        select * from user where name = #{name} and pwd=#{pwd};
    </select>

</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.List;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserByNameAndPwd(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByNameAndPwd("张三", "abcde");
        for (User user :
                users) {
            System.out.println(user);
        }
    }
}

第二种方法

使用Map进行传输

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);

    //通过name、pwd值进行查询
    List<User> selectUserByNameAndPwd(Map<String, String> map);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>

    <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map">
        select * from user where name = #{name} and pwd=#{pwd};
    </select>

</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserByNameAndPwd(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        Map<String, String> map = new HashMap<String, String>();
        map.put("name", "张三");
        map.put("pwd", "abcde");
        List<User> users = userMapper.selectUserByNameAndPwd(map);
        for (User user :
                users) {
            System.out.println(user);
        }
    }
}

模糊查询

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;


import java.util.List;
import java.util.Map;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);

    //通过name、pwd值进行查询
    List<User> selectUserByNameAndPwd(Map<String, String> map);

    List<User> selectUserLikeName(String str);
    //插入
    int insertUser(User user);

    //更新
    int updateUser(User user);

    //删除
    int deleteUser(User user);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>

    <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map">
        select * from user where name = #{name} and pwd=#{pwd};
    </select>

    <select id="selectUserLikeName" parameterType="String" resultType="com.sicheng.entity.User">
        select * from user where name like "%"#{str};
    </select>

    <insert id="insertUser" parameterType="com.sicheng.entity.User">
        insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd});
    </insert>

    <update id="updateUser" parameterType="com.sicheng.entity.User">
        update user set name=#{name},pwd=#{pwd} where id=#{id};
    </update>

    <delete id="deleteUser" parameterType="com.sicheng.entity.User">
        delete from user where id=#{id};
    </delete>
</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserByNameAndPwd(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        Map<String, String> map = new HashMap<String, String>();
        map.put("name", "张三");
        map.put("pwd", "abcde");
        List<User> users = userMapper.selectUserByNameAndPwd(map);
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserLikeName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserLikeName("四");
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void insertUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.insertUser(new User(4, "李思成", "12345"));
        System.out.println(flag);
        session.commit();
    }

    @Test
    public void updateUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.updateUser(new User(4, "江GG", "12345"));
        System.out.println(flag);
        session.commit();
    }

    @Test
    public void deleteUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.deleteUser(new User(4, "江GG", "12345"));
        System.out.println(flag);
        session.commit();
    }
}

插入

没有resultType

并且记住session.commit。提交事务

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);

    //通过name、pwd值进行查询
    List<User> selectUserByNameAndPwd(Map<String, String> map);

    //插入
    int insertUser(User user);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>

    <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map">
        select * from user where name = #{name} and pwd=#{pwd};
    </select>

    <insert id="insertUser" parameterType="com.sicheng.entity.User">
        insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd});
    </insert>
</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserByNameAndPwd(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        Map<String, String> map = new HashMap<String, String>();
        map.put("name", "张三");
        map.put("pwd", "abcde");
        List<User> users = userMapper.selectUserByNameAndPwd(map);
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void insertUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.insertUser(new User(4, "李思成", "12345"));
        System.out.println(flag);
        session.commit();
    }
}

更新

记住一定要提交

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);

    //通过name、pwd值进行查询
    List<User> selectUserByNameAndPwd(Map<String, String> map);

    //插入
    int insertUser(User user);

    //更新
    int updateUser(User user);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>

    <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map">
        select * from user where name = #{name} and pwd=#{pwd};
    </select>

    <insert id="insertUser" parameterType="com.sicheng.entity.User">
        insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd});
    </insert>

    <update id="updateUser" parameterType="com.sicheng.entity.User">
        update user set name=#{name},pwd=#{pwd} where id=#{id};
    </update>
</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserByNameAndPwd(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        Map<String, String> map = new HashMap<String, String>();
        map.put("name", "张三");
        map.put("pwd", "abcde");
        List<User> users = userMapper.selectUserByNameAndPwd(map);
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void insertUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.insertUser(new User(4, "李思成", "12345"));
        System.out.println(flag);
        session.commit();
    }

    @Test
    public void updateUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.updateUser(new User(4, "江GG", "12345"));
        System.out.println(flag);
        session.commit();
    }
}

删除

dao类

package com.sicheng.dao;

import com.sicheng.entity.User;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface UserMapper {

    //猛查
    List<User> selectUser();

    //通过ID查
    User selectUserById(int id);

    //通过name属性查
    List<User> selectUserByName(String name);

    //通过name、pwd值进行查询
    List<User> selectUserByNameAndPwd(Map<String, String> map);

    //插入
    int insertUser(User user);

    //更新
    int updateUser(User user);

    //删除
    int deleteUser(User user);
}

mapper配置文件

<?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="com.sicheng.dao.UserMapper">
    <select id="selectUser" resultType="com.sicheng.entity.User">
        select * from user;
    </select>

    <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int">
        select * from user where id=#{id}
    </select>

    <select id="selectUserByName" resultType="com.sicheng.entity.User">
        select * from user where name = #{name};
    </select>

    <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map">
        select * from user where name = #{name} and pwd=#{pwd};
    </select>

    <insert id="insertUser" parameterType="com.sicheng.entity.User">
        insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd});
    </insert>

    <update id="updateUser" parameterType="com.sicheng.entity.User">
        update user set name=#{name},pwd=#{pwd} where id=#{id};
    </update>

    <delete id="deleteUser" parameterType="com.sicheng.entity.User">
        delete from user where id=#{id};
    </delete>
</mapper>

test文件

import com.sicheng.dao.UserMapper;
import com.sicheng.entity.User;
import com.sicheng.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MybatisTest {

    @Test
    public void selectUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUser();
        for (User user :users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserById(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        User user = userMapper.selectUserById(2);
        System.out.println(user);
    }

    @Test
    public void selectUserByName(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        List<User> users = userMapper.selectUserByName("张三");
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void selectUserByNameAndPwd(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        Map<String, String> map = new HashMap<String, String>();
        map.put("name", "张三");
        map.put("pwd", "abcde");
        List<User> users = userMapper.selectUserByNameAndPwd(map);
        for (User user :
                users) {
            System.out.println(user);
        }
    }

    @Test
    public void insertUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.insertUser(new User(4, "李思成", "12345"));
        System.out.println(flag);
        session.commit();
    }

    @Test
    public void updateUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.updateUser(new User(4, "江GG", "12345"));
        System.out.println(flag);
        session.commit();
    }

    @Test
    public void deleteUser(){
        SqlSession session = MybatisUtils.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        int flag = userMapper.deleteUser(new User(4, "江GG", "12345"));
        System.out.println(flag);
        session.commit();
    }
}

posted @ 2020-06-16 14:18 梦想成为DALAO 阅读(235) 评论(0) 编辑收藏举报

会员力量，点亮园子希望

刷新页面返回顶部

梦想成为DALAO

1-----Mybatis

没有mybatis

建表

查询

statement与preparedment

mybatis

简介

持久化

持久层

为什么需要mybatis

简单的mybatis程序

mybatis的执行流程

实体类-----Lombok插件有问题，导不进去

查找类---也就是dao类

Mybatis的配置文件

与dao类相互映射的，mapper文件

MybatisUtils

Test

注意事项

补充知识

xml中的 &amp; 是个啥？

数据库连接中

Resources类

Resources类的常用情况

Resources类加载一个资源的方式

根据加载方式不同，加载资源的方法如下

继续各种操作吧

查询

通过主键ID查询

dao类

mapper文件

注意一下：

Test文件

通过name属性查询

dao类

mapper配置文件

test文件

通过根据密码、名字查询

第一种方法

dao类

mapper配置文件

test文件

第二种方法

dao类

mapper配置文件

test文件

模糊查询

dao类

mapper配置文件

test文件

插入

dao类

mapper配置文件

test文件

更新

dao类

mapper配置文件

test文件

删除

dao类

mapper配置文件

test文件

公告

xml中的 & 是个啥？