Mybatis环境搭建<0>

mybatis官方中文文档

IDE：intellij
构建工具：gradle
框架：mybatis

配置好后的结构如图：

配置好的工程结构图.png

1. 首先添加mybatis和数据库连接jar包
   build.gradle

group 'com.study.mybatis'
version '1.0-SNAPSHOT'

apply plugin: 'java'
apply plugin: 'war'

sourceCompatibility = 1.8

repositories {
    mavenCentral()
}

dependencies {
    // https://mvnrepository.com/artifact/org.mybatis/mybatis
    compile group: 'org.mybatis', name: 'mybatis', version: '3.4.4'
    // https://mvnrepository.com/artifact/mysql/mysql-connector-java
    compile group: 'mysql', name: 'mysql-connector-java', version: '5.1.43'

    testCompile group: 'junit', name: 'junit', version: '4.11'
    testCompile group: 'junit', name: 'junit', version: '4.12'
}

2. 在数据库中添加几条数据

image.png

3.配置连接
mybatis-config.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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/studymybatis?characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/BlogMapper.xml"/>
    </mappers>
</configuration>

4. 代码部分
   Blog.java

package com.study.mybatis.model;

/**
 * Created by  on 2017/8/9.
 */
public class Blog {
    int id;
    String author;

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

BlogMapper.java

package com.study.mybatis.mapper;

import com.study.mybatis.model.Blog;

/**
 * Created by liuqun on 2017/8/9.
 */

public interface BlogMapper {
    Blog selectBlog(int id);
}

BlogMapper.xml

<?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.study.mybatis.mapper.BlogMapper">
    <select id="selectBlog" resultType="com.study.mybatis.model.Blog">
        select * from Blog where id = #{id}
    </select>
</mapper>

import com.study.mybatis.mapper.BlogMapper;
import com.study.mybatis.model.Blog;
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;

/**
 * Created by liuqun on 2017/8/9.
 */
public class Test {

     public static void main(String[] args) throws IOException {
         String resource = "mybatis-config.xml";
         InputStream inputStream = Resources.getResourceAsStream(resource);
         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
         SqlSession session = sqlSessionFactory.openSession();
         try {
             BlogMapper mapper = session.getMapper(BlogMapper.class);
             Blog blog = mapper.selectBlog(101);
             System.out.println(blog.toString());
         } finally {
             session.close();
         }
     }
}

最后运行结果

Blog{id=101, author='王五'}

5. 第二种方式使用注解
   BlogMapper.java

package com.study.mybatis.mapper;

import com.study.mybatis.model.Blog;
import org.apache.ibatis.annotations.Select;

/**
 * Created by liuqun on 2017/8/9.
 */

public interface BlogMapper {
    @Select("SELECT * FROM blog WHERE id = #{id}")
    Blog selectBlog(int id);
}

使用代码配置也可以，将BlogMapp.class注册到配置里，运行结果和上面是一样的

  PooledDataSource dataSource = new PooledDataSource();
         dataSource.setDriver("com.mysql.jdbc.Driver");
         dataSource.setUrl("jdbc:mysql://localhost:3306/studymybatis?characterEncoding=utf-8");
         dataSource.setUsername("root");
         dataSource.setPassword("root");
         TransactionFactory transactionFactory = new JdbcTransactionFactory();
         Environment environment = new Environment("development", transactionFactory, dataSource);
         Configuration configuration = new Configuration(environment);
         configuration.addMapper(BlogMapper.class);
         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(configuration);
         SqlSession session = sqlSessionFactory.openSession();
         try {
             BlogMapper mapper = session.getMapper(BlogMapper.class);
             Blog blog = mapper.selectBlog(101);
             System.out.println(blog.toString());
         } finally {
             session.close();
         }