第一个程序

Posted 2020-10-26 龙宇在天

1.工程目录结构

2.需要导入的jar包

除了和外，其他的都是mybatis的核心包，直接可以在官网下载。

3.具体程序

package com.bjpowernode.beans;

public class Student {
    private Integer id;
    private String name;
    private int age;
    private double score;
    public Student() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Student(String name, int age, double score) {
        super();
        this.name = name;
        this.age = age;
        this.score = score;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    public double getScore() {
        return score;
    }
    public void setScore(double score) {
        this.score = score;
    }
    @Override
    public String toString() {
        return "Student [name=" + name + ", age=" + age + ", score=" + score + "]";
    }
    
}

Student.java

成员变量和属性的区别？

成员变量--实体类中private修饰的字段

属性--实体类中get/set方法名去除get/set后的名称首字母小写

package com.bjpowernode.dao;

import com.bjpowernode.beans.Student;

public interface IStudentDao {
    void insertStu(Student student);
}

IStudentDao.java

package com.bjpowernode.dao;

import java.io.IOException;
import java.io.InputStream;
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;

import com.bjpowernode.beans.Student;

public class StudentDaoImpl implements IStudentDao {

    private SqlSession sqlsession;

    @Override
    public void insertStu(Student student) {
        InputStream inputStream;
        try {
            //1.加载主配置文件
            inputStream = Resources.getResourceAsStream("mybatis.xml");
            //2.创建SqlSessionFactory对象
            SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            //3.创建sqlsession对象
            sqlsession = sqlSessionFactory.openSession();
            //4.执行相关操作
            //此处的statement指的是映射文件中相关操作的id
            sqlsession.insert("insertStudent", student);
            sqlsession.commit();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            if(sqlsession != null) {
                sqlsession.close();
            }
        }
    }

}

StudentDaoImpl.java

package com.bjpowernode.test;

import org.junit.Before;
import org.junit.Test;

import com.bjpowernode.beans.Student;
import com.bjpowernode.dao.IStudentDao;
import com.bjpowernode.dao.StudentDaoImpl;

public class MyTest {
    private IStudentDao dao;
    
    @Before
    public void before() {
        dao = new StudentDaoImpl();
    }
    
    @Test
    public void testInsert() {
        Student student = new Student("张三1",30,99.6);
        dao.insertStu(student);
    }
}

MyTest.java

log4j.appender.console=org.apache.log4j.ConsoleAppender
log4j.appender.console.Target=System.out
log4j.appender.console.layout=org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=[%-5p][%d{yyyy-MM-dd HH:mm:ss}] %c %L %m%n
#log4j.appender.console.layout.ConversionPattern=[%-5p] %m%n

##define a logger
#此处的test表示mapper的namespace的名称
log4j.logger.test=debug,console 
#log4j.rootLogger=debug,console

log4j.properties

mapper.xml-映射文件

<?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="test">
    <insert id="insertStudent" parameterType="com.bjpowernode.beans.Student">
        <!-- name、age、score是对应参数的属性名，此处属性名刚好和成员变量名称相同 -->
        insert into student(name,age,score) values(#{name}, #{age}, #{score})
    </insert>
</mapper>

xml文件中的一些小的提示技巧？

选中指定标签，按f2会出现提示框，提示内容如下

Content Model : (properties?, settings?, typeAliases?,
typeHandlers?, objectFactory?, objectWrapperFactory?,
reflectorFactory?, plugins?, environments?,
databaseIdProvider?, mappers?)

其中逗号表示有先后顺序，“*”表示0个或多个，“+”表示一个或多个，“？”表示0个或一个

mybatis.xml-主配置文件

<?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>
    <!-- 配置运行环境 -->
    <environments default="testEn">
        <!-- 测试环境 -->
        <environment id="testEn">
            <!--事务管理器 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- mybatis自带的数据库连接池POOLED，连接池是数据源的一种 -->
            <dataSource type="POOLED">
                <!--数据库连接池四要素  -->
                <!-- 加载驱动，value对应着所需的驱动类名，底层用反射来实现 -->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/test"/>
                <!-- 如果端口号用的是经典端口号3306，ip和port可以省略不写，如下形式 -->
                <!-- <property name="url" value="jdbc:mysql:///test"/> -->
                <property name="username" value="root"/>
                <property name="password" value="123"/>
            </dataSource>
        </environment>
        <!-- 上线环境 -->
        <environment id="onlineEn">
            <!--事务管理器 -->
            <transactionManager type="JDBC"></transactionManager>
            <!-- mybatis自带的数据库连接池POOLED，连接池是数据源的一种 -->
            <dataSource type="POOLED">
                <!--数据库连接池四要素  -->
                <!-- 加载驱动，value对应着所需的驱动类名，底层用反射来实现 -->
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://127.0.0.1:3306/test"/>
                <!-- 如果端口号用的是经典端口号3306，ip和port可以省略不写，如下形式 -->
                <!-- <property name="url" value="jdbc:mysql:///test"/> -->
                <property name="username" value="root"/>
                <property name="password" value="123"/>
            </dataSource>
        </environment>
    </environments>
    <!-- 注册映射文件 -->
    <mappers>
        <mapper resource="com/bjpowernode/dao/mapper.xml"/>
    </mappers>
</configuration>