mybatis —注解环境搭建

mybatis的注解环境搭建

1，创建一个maven工程

2，pom.xml 配置环境

<?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>com.itheima</groupId>
    <artifactId>day04_eesy_01lazy</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.encoding>UTF-8</maven.compiler.encoding>

        <java.version>1.8</java.version>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.10</version>
        </dependency>
    </dependencies>

</project>

3，user类

user类是与数据库中指定数据表的字段一一对应的实体类

package com.itheima.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable {
    private Integer id;
    private String username;
    private String address;
    private String sex;
    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 getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", address='" + address + '\'' +
                ", sex='" + sex + '\'' +
                ", birthday=" + birthday +
                '}';
    }

}

4，IUserDao类

实现与数据库查询所有 操作的接口

package com.itheima.dao;

        import com.itheima.domain.User;
        import org.apache.ibatis.annotations.Select;

        import java.util.List;

/**
 *在mybatis中针对crud一共有四个注解
 * @Select @Insert @update @delete
 */
public interface IUserDao {
    /**
     * 查询所有用户
     * @return
     */
    @Select(value ="select * from user")
    List<User> findAll();
}

5，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>
    <!-- 引入外部配置文件-->
    <properties resource="jdbcConfig.properties"></properties>
    <!--配置别名--> <!--使用typeAliases配置别名，它只能配置domain中类的别名 -->
    <typeAliases>
        <package name="com.itheima.domain"></package>
    </typeAliases>

    <!--配置环境-->
    <environments default="mysql">
        <environment id="mysql">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"></property>
                <property name="url" value="${jdbc.url}"></property>
                <property name="username" value="${jdbc.username}"></property>
                <property name="password" value="${jdbc.password}"></property>
            </dataSource>
        </environment>
    </environments>
    <!--指定带有注解的dao接口所在位置，即映射文件所在位置 -->
    <mappers>
        <package name="com.itheima.dao"></package>
    </mappers>

</configuration>

6,测试类

package com.itheima.test;

import com.itheima.dao.IUserDao;
import com.itheima.domain.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.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MybatisAnnoTest {
    /**
     * 测试基于注解的mybatis使用
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        InputStream inputStream = new FileInputStream("SqlMapConfig.xml"); // 相对路径,项目下的路径
        //1.读取配置文件，生成字节输入流
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //2.根据字节输入流构建 获取SqlSessionFactory
        SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
        //3.根据SqlSessionFactory获取SqlSession对象
        SqlSession session = factory.openSession(true);
        //4.使用SqlSession获取dao的代理对象
        IUserDao userDao = session.getMapper(IUserDao.class);
        //5.执行Dao的方法
        List<User> users = userDao.findAll();
        for (User user : users){
            System.out.println(user);
        }
        //6.释放资源
        session.close();
        in.close();
    }
}

配置完成后的目录

注解形式相对于xml形式少了Dao映射文件夹，方便很多。