MyBatis_Day02

liuboss 2020-10-20

162

一,mybatis实现查询增加完整步骤。查询，插入操作。

1.创建数据库，数据库名称，属性，user表中的属性包括，id,name,pwd。

2..配置pom文件引入相关jar包进行导入。并引入log4j的日志文件到resources文件目录下。

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>Mybatis01</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>


    <artifactId>Test01</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>Test01</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.20</version>
        </dependency>
    </dependencies>
</project>

3.创建与数据库对应的类，创建对应的数据类型以及数据字段名称。

包com.liuboss.demo,创建类User。

---实现其中的get,set，toString方法。

package com.liuboss.demo;






public class User {
    private int id;
    private String name;
    private String pwd;


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

4.在resources文件下创建配置文件进行，实现数据库操作语句。

com.liuboss.demo包,创建配置文件MybatisConfig.xml。

注意：命名空间和id值的配置。

<?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="userMapper">


    <select id="userAll" resultType="com.liuboss.demo.User">
        select * from user
    </select>
    <insert id="save" parameterType="com.liuboss.demo.User">
        insert into user value(#{id},#{name},#{pwd})
    </insert>
</mapper>

5.配置数据库链接文件。MybatisSqlConfig.xml

---其中数据库连接文件，里面要进行数据库操作文件的关联

<?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">
<!--mybatis核心配置文件-->
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url"
                          value="jdbc:mysql://localhost:3306/mybatis?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8&amp;serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com\liuboss\demo\MybatisConfig.xml"/>
    </mappers>
</configuration>

6.测试文件。

package com.liuboss.demo;


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;
import java.util.List;


public class Test {
    @org.junit.Test
    public void test1() throws IOException {
        //获得核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("MybatisSqlConfig.xml");
        //获得session工厂对象
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = build.openSession();
        //执行操作  参数，namespqce+id
        List<User> userList = sqlSession.selectList("userMapper.userAll");
        //打印数据
        System.out.println(userList);
        //释放资源
        sqlSession.close();


    }
    @org.junit.Test
    public void test2() throws IOException {
        User user=new User();
        user.setId(57);
        user.setName("金刚");
        user.setPwd("123");
        //获得核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("MybatisSqlConfig.xml");
        //获得session工厂对象
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = build.openSession();
        //执行操作  参数，namespqce+id
        sqlSession.insert("userMapper.save",user);
        sqlSession.commit();
        //释放资源
        sqlSession.close();


    }
}

---在数据库的文件添加中，要提交事务，数据才可以添加成功。

二。mybaits实现增删改查代码实现

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>


    <groupId>org.example</groupId>
    <artifactId>Mybatis01</artifactId>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>Test01</module>
    </modules>


    <dependencies>


        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.20</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>


    </dependencies>


</project>

package com.liuboss.demo;


public class User {
    private int id;
    private String name;


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


    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;
    }
}

<?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="userMapper">
    <!--查询操作-->
    <select id="findAll" resultType="com.liuboss.demo.User">
        select * from t_class
    </select>


    <!--插入操作-->
    <insert id="save" parameterType="com.liuboss.demo.User">
        insert into t_class value(#{id},#{name})
    </insert>


    <!--数据库的修改操作-->
    <update id="update" parameterType="com.liuboss.demo.User">
        update t_class set name=#{name} where id=#{id}
    </update>


    <!--数据库的删除操作-->
    <delete id="delete" parameterType="com.liuboss.demo.User">
        delete from t_class where id=#{id}
    </delete>


</mapper>

<?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">
<!--mybatis核心配置文件-->
<!--配置数据源环境-->
<configuration>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/text01?serverTimezone=UTC"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>


            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="com\liuboss\mapper\UserMapper.xml"></mapper>
    </mappers>
</configuration>

package com.liuboss.demo;


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.Test;


import java.io.IOException;
import java.io.InputStream;
import java.util.List;


public class MyBatis {
    @Test
    public void test1() throws IOException {
        //获得核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        //获得session工厂对象
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = build.openSession();
        //执行操作  参数，namespqce+id
        List<User> userList = sqlSession.selectList("userMapper.findAll");
        //打印数据
        System.out.println(userList);
        //释放资源
        sqlSession.close();


    }
    @Test
    public void test2() throws IOException {
        //模拟user对象
        User user=new User();
        user.setId(6);
        user.setName("马云人自己");


        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        //获得session工厂对象
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = build.openSession();
        //执行操作  参数，namespqce+id
        sqlSession.insert("userMapper.save",user);
        sqlSession.commit();
        //释放资源
        sqlSession.close();
    }
    /*更新操作*/
    @Test
    public void test3() throws IOException {
        //模拟user对象
        User user=new User();
        user.setId(6);
        user.setName("永乐大帝");


        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        //获得session工厂对象
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = build.openSession();
        //执行操作  参数，namespqce+id
        sqlSession.update("userMapper.update",user);
        sqlSession.commit();
        //释放资源
        sqlSession.close();
    }
    /*删除操作*/
    @Test
    public void test4() throws IOException {
        //模拟user对象
        User user=new User();
        user.setId(7);








        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        //获得session工厂对象
        SqlSessionFactory build = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //获得session会话对象
        SqlSession sqlSession = build.openSession();
        //执行操作  参数，namespqce+id
        sqlSession.update("userMapper.delete",7);
        sqlSession.commit();
        //释放资源
        sqlSession.close();
    }
}

三。mybatis小配置文件的配置。简化配置可以随意修改

在resources文件下创建配置文件jdbc.properties配置数据库连接

jdbc.driver = com.mysql.cj.jdbc.Driver
jdbc.url = jdbc:mysql://localhost:3306/text01?serverTimezone=UTC
jdbc.username = root
jdbc.password = 123456

2.在sqlMapConfig.xml配置文件中引入jdbc小配置文件

<properties resource="jdbc.properties"></properties>

---并将其中的数据库配置修改为jdbc.properties中的相关配置名称

<?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">
<!--mybatis核心配置文件-->
<!--配置数据源环境-->
<configuration>
    <properties resource="jdbc.properties"></properties>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <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>
    <mappers>
        <mapper resource="com\liuboss\mapper\UserMapper.xml"></mapper>
    </mappers>
</configuration>

配置完成进行测试，测试配置是否成功。

四，配置文件中别名的配置

将别名进行配置方便开发，简化代码。

<!--自定义别名  重点：自定义别名的顺序，typeAliases标签只能放在数据库连接文件之前-->
    <typeAliases>
        <typeAlias type="com.liuboss.demo.User" alias="user"></typeAlias>
    </typeAliases>

<?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">
<!--mybatis核心配置文件-->
<!--配置数据源环境-->
<configuration>
    <properties resource="jdbc.properties"></properties>
    <!--自定义别名  重点：自定义别名的顺序，typeAliases标签只能放在数据库连接文件之前-->
    <typeAliases>
        <typeAlias type="com.liuboss.demo.User" alias="user"></typeAlias>
    </typeAliases>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <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>
    <mappers>
        <mapper resource="com\liuboss\mapper\UserMapper.xml"></mapper>
    </mappers>


</configuration>

别名配置后的使用。简化开发

<?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="userMapper">
    <!--查询操作-->
    <select id="findAll" resultType="user">
        select * from t_class
    </select>
    <!--插入操作-->
    <insert id="save" parameterType="user">
        insert into t_class value(#{id},#{name})
    </insert>
    <!--数据库的修改操作-->
    <update id="update" parameterType="user">
        update t_class set name=#{name} where id=#{id}
    </update>
    <!--数据库的删除操作-->
    <delete id="delete" parameterType="user">
        delete from t_class where id=#{id}
    </delete>
</mapper>

---存在的数据类型不用定义别名直接使用即可

当openSession设置为true时，将自动提交事务，不用手动提交事务。

//获得session会话对象
        SqlSession sqlSession = build.openSession(true);

数据库

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MyBatis_Day02

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