mybatis读数据库

create table `Blog`( `id` INT(11) NOT NULL AUTO_INCREMENT, `name` CHAR(20) DEFAULT '' COMMENT '名字', PRIMARY KEY(`id`)
)COMMENT="博客";
INSERT INTO Blog (id,name) VALUES (101,'nick');
INSERT INTO Blog (name) VALUES ('nickqiu');

<?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.nick</groupId> <artifactId>mybatis-demo</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.6</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.16.20</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.46</version> </dependency> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> <version>2.8.4</version> </dependency> </dependencies>
</project>

<?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/test"/> <property name="username" value="root"/> <property name="password" value="123456"/> <!--<property name="url" value="${url}"/>--> <!--<property name="username" value="${username}"/>--> <!--<property name="password" value="${password}"/>--> </dataSource> </environment> </environments> <mappers> <mapper resource="sqlmapping/BlogMapper.xml"/> </mappers>
</configuration>

<?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="org.nick.mybatistest.BlogMapper"> <select id="selectBlog" resultType="org.nick.mybatistest.entity.Blog"> select * from Blog where id = #{id}
  </select>
</mapper>

package org.nick.mybatistest.entity;
import lombok.Data;
@Data
public class Blog { private int id; private String name;
}

package org.nick.mybatistest.dao;

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;
/**
 * 链接数据库
 */
public class DbConnect { private static SqlSessionFactory sqlSessionFactory = null; private static String resource = "mybatis-config.xml"; private static synchronized void get(){ if(sqlSessionFactory == null){ InputStream inputStream = null; try { inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch ( IOException e) { e.printStackTrace(); } } } public static SqlSession  getSqlSection(){ get(); SqlSession session = sqlSessionFactory.openSession(); return  session; }

}

package org.nick.mybatistest;

import com.google.gson.Gson;
import org.apache.ibatis.session.SqlSession;
import org.nick.mybatistest.dao.DbConnect;
import org.nick.mybatistest.entity.Blog;

public class Application { public static void main(String[] args) { SqlSession session = DbConnect.getSqlSection(); try { Blog blog = (Blog) session.selectOne("org.nick.mybatistest.BlogMapper.selectBlog", 101); System.out.println("blog:"+new Gson().toJson(blog)); } finally { session.close(); } }
}

package org.nick.mybatistest.dao;

import org.apache.ibatis.annotations.Select;
import org.nick.mybatistest.entity.Blog;

public interface BlogMapper1 { @Select("SELECT * FROM blog WHERE id = #{id}") Blog selectBlog(int id);
}

 package org.nick.mybatistest.dao;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.Configuration;
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;


/**
 * 链接数据库
 */
public class DbConnect { private static SqlSessionFactory sqlSessionFactory = null; private static String resource = "mybatis-config.xml"; private static synchronized void get(){ if(sqlSessionFactory == null){ InputStream inputStream = null; try { inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); Configuration configuration = sqlSessionFactory.getConfiguration(); configuration.addMapper(BlogMapper1.class); } catch ( IOException e) { e.printStackTrace(); } } } public static SqlSession  getSqlSection(){ get(); SqlSession session = sqlSessionFactory.openSession(); return  session; }

}

package org.nick.mybatistest;

import com.google.gson.Gson;
import org.apache.ibatis.session.SqlSession;
import org.nick.mybatistest.dao.BlogMapper1;
import org.nick.mybatistest.dao.DbConnect;
import org.nick.mybatistest.entity.Blog;

public class Application1 { public static void main(String[] args) { SqlSession session = DbConnect.getSqlSection(); try { BlogMapper1 mapper = session.getMapper(BlogMapper1.class); Blog blog = mapper.selectBlog(101); System.out.println("blog:"+new Gson().toJson(blog)); } finally { session.close(); } }
}