java actual application: MyBatis additions and deletions to achieve a single table

MyBatis supports common SQL queries. Excellent persistence framework stored procedures and advanced mappings. MyBatis eliminates almost all of the retrieved code and JDBC manually set parameters and the result set. MyBatis uses a simple XML or Annotations for configuration and map primitives, Map interfaces and Java POJOs (Plain Old Java Objects, ordinary Java Objects) to database records in.

Each application are mainly used MyBatis SqlSessionFactory instance, can be obtained by a SqlSessionFactory instance SqlSessionFactoryBuilder. SqlSessionFactoryBuilder from an xml file can be configured or example of the configuration of a class defined in advance is obtained.
Construction of SqlSessionFactory instance with the xml file is very easy to do.

Recommended classpath resources (classpath resource) in this configuration. But you can use whatever Reader instance, contains a file path or file: // at the beginning of the url instance created.

MyBatis has a useful classes ---- Resources, which has a lot of methods. Resources can be easily loaded from the classpath and other locations.

 A first establish the overall renderings of the project:

The following is a table of single CRUD MyBatis:

Second, the item code:
1) entity classes: News of:

public class News {
	private Integer id;
	private String title;
	private String content;
	private Date pubDate;
	private Integer typeId;
	private String photo;
	private String tname;
	//get,set方式省去

2) dao layer excuse layer INewsDAO:

import java.util.List;
import java.util.Map;
import org.liky.vo.News;

public interface INewsDAO {

	public void doCreate(News news) throws Exception;
	public void doUpdate(News news) throws Exception;
	public void doRemove(int id) throws Exception;
	public List<News> findAll() throws Exception;
	public News findById(int id) throws Exception;
	public List<News> findAllSplit(Map<String, Object> map) throws Exception;
	public int getAllCount(Map<String, Object> map) throws Exception;

}

3) achieve dao layer. INewDAO.xml, normal is not myBatis, here is the write implementation class dao layer: myBatis advantage is also here, drawn out of the sql statement written to a separate xml, easy to manage databases.

It is closer to the jdbc. Therefore, the processing speed is very fast, which is outside the network need to use the project frame.

<mapper namespace="org.liky.dao.INewsDAO">

	<resultMap type="News" id="NewsResult">
		<id column="id" property="id" />
		<result column="title" property="title" />
		<result column="content" property="content" />
		<result column="pub_date" property="pubDate" />
		<result column="type_id" property="typeId" />
		<result column="photo" property="photo" />
	</resultMap>

	<insert id="doCreate" parameterType="News">
		INSERT INTO news
		(id,title,content,pub_date,type_id,photo) VALUES
		(news_seq.nextVal,#{title},#{content},#{pubDate},#{typeId},#{photo})
	</insert>

	<update id="doUpdate" parameterType="News">
		UPDATE news
		SET title =
		#{title},content=#{content},pub_date = #{pubDate},type_id =
		#{typeId},photo=#{photo}
		WHERE id = #{id}
	</update>

	<delete id="doRemove" parameterType="java.lang.Integer">
		DELETE FROM news WHERE id =
		#{id}
	</delete>

	<select id="findAll" resultMap="NewsResult">
		SELECT * FROM news
	</select>

	<select id="findById" resultType="News" parameterType="java.lang.Integer">
		SELECT
		id,title,content,pub_date AS pubDate,type_id AS typeId,photo,tname FROM news n,news_type nt
		WHERE id = #{id} AND n.type_id = nt.tid
	</select>

	<select id="findAllSplit" resultType="News" parameterType="java.util.Map">
		SELECT temp.* FROM (SELECT
		id,title,content,pub_date
		AS pubDate,type_id
		AS typeId,photo,ROWNUM rn
		FROM news WHERE ${column}
		LIKE #{keyword} AND
		ROWNUM <= #{endNumber}) temp WHERE temp.rn >
		#{startNumber}		 
	</select>

	<select id="getAllCount" resultType="int" parameterType="java.util.Map">
		SELECT
		COUNT(*) FROM news WHERE ${column} LIKE #{keyword}
	</select>

</mapper>

4) This step can write mybatis overall profile, initial load connected to the database.

<configuration>
	<typeAliases>
		<package name="org.liky.vo" />
	</typeAliases>
	<environments default="development">
		<environment id="development">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="oracle.jdbc.driver.OracleDriver" />
				<property name="url" value="jdbc:oracle:thin:@localhost:1521:ORCL" />
				<property name="username" value="sunxun" />
				<property name="password" value="123" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<mapper resource="org/liky/dao/INewsDAO.xml" />
	</mappers>
</configuration>

5) establish MyBATISSqlSessionFactory categories:

import java.io.InputStream;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBATISSqlSessionFactory {

	// 配置文件的所在位置和名称
	private static String CONFIG_FILE_LOCATION = "mybatis-config.xml";

	// 用来实现连接池的。该类相似Map集合。
	private static final ThreadLocal<SqlSession> threadLocal = new ThreadLocal<SqlSession>();
	// Hibernate用来读取配置文件的类
	private static InputStream is;
	// 用来建立连接的，该类就是连接池，使用单例设计模式
	private static SqlSessionFactory sqlsessionFactory;
	// 备用的配置文件位置
	private static String configFile = CONFIG_FILE_LOCATION;

	// 静态块，类载入时最先运行
	static {
		try {
			// 载入配置文件到内存中
			is = Resources.getResourceAsStream(configFile);
			// 建立连接池以及里面的连接
			sqlsessionFactory = new SqlSessionFactoryBuilder().build(is);
		} catch (Exception e) {
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
	}

	private MyBATISSqlSessionFactory() {
	}

	/**
	 * 取得数据库连接对象
	 * 
	 * @return Session
	 * @throws HibernateException
	 */
	public static SqlSession getSession() {
		// 先从ThreadLocal中取得连接。
		SqlSession session = (SqlSession) threadLocal.get();

		// 假设手头没有连接，则取得一个新的连接
		if (session == null) {
			session = sqlsessionFactory.openSession();
			// 把取得出的连接记录到ThreadLocal中，以便下次使用。
			threadLocal.set(session);
		}
		return session;
	}

	/**
	 * 连接关闭的方法
	 * 
	 * @throws HibernateException
	 */
	public static void closeSession() {
		SqlSession session = (SqlSession) threadLocal.get();
		// 将ThreadLocal清空，表示当前线程已经没有连接。

		threadLocal.set(null);
		// 连接放回到连接池
		if (session != null) {
			session.close();
		}
	}
}

6) Write a pretext service layer implementation:

import java.util.List;
import java.util.Map;
import org.liky.vo.News;

public interface INewsService {

	public void insert(News news) throws Exception;

	public News findById(int id) throws Exception;

	public List<News> findAll() throws Exception;

	public Map<String, Object> list(int pageNo, int pageSize, String column,
			String keyword) throws Exception;

}

7) decoupling, write service factory:

import org.liky.service.INewsService;
import org.liky.service.impl.NewsServiceImpl;

public class ServiceFactory {

	public static INewsService getINewsServiceInstance() {
		return new NewsServiceImpl();
	}
}

8) service implementation class:

import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.liky.dao.INewsDAO;
import org.liky.dbc.MyBATISSqlSessionFactory;
import org.liky.service.INewsService;
import org.liky.vo.News;

public class NewsServiceImpl implements INewsService {

	public List<News> findAll() throws Exception {
		List<News> all = null;
		try {
			all = MyBATISSqlSessionFactory.getSession().getMapper(
					INewsDAO.class).findAll();
		} catch (Exception e) {
			e.printStackTrace();
			throw e;
		} finally {
			MyBATISSqlSessionFactory.closeSession();
		}
		return all;
	}

	public News findById(int id) throws Exception {
		News news = null;
		try {
			news = MyBATISSqlSessionFactory.getSession().getMapper(
					INewsDAO.class).findById(id);
		} catch (Exception e) {
			e.printStackTrace();
			throw e;
		} finally {
			MyBATISSqlSessionFactory.closeSession();
		}
		return news;
	}

	public void insert(News news) throws Exception {
		try {
			MyBATISSqlSessionFactory.getSession().getMapper(INewsDAO.class)
					.doCreate(news);
			MyBATISSqlSessionFactory.getSession().commit();
		} catch (Exception e) {
			e.printStackTrace();
			MyBATISSqlSessionFactory.getSession().rollback();
			throw e;
		} finally {
			MyBATISSqlSessionFactory.closeSession();
		}
	}

	public Map<String, Object> list(int pageNo, int pageSize, String column,
			String keyword) throws Exception {
		Map<String, Object> map = new HashMap<String, Object>();
		// 设置要向DAO中传递的參数
		Map<String, Object> params = new HashMap<String, Object>();
		params.put("column", column);
		params.put("keyword", "%" + keyword + "%");
		params.put("endNumber", pageNo * pageSize);
		params.put("startNumber", (pageNo - 1) * pageSize);
		try {
			map.put("allNews", MyBATISSqlSessionFactory.getSession().getMapper(
					INewsDAO.class).findAllSplit(params));
			map.put("count", MyBATISSqlSessionFactory.getSession().getMapper(
					INewsDAO.class).getAllCount(params));
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			MyBATISSqlSessionFactory.closeSession();
		}
		return map;
	}
}

9) test class NewsServiceImplTest:

import java.util.Date;
import java.util.UUID;
import org.junit.Test;
import org.liky.factory.ServiceFactory;
import org.liky.vo.News;
public class NewsServiceImplTest {

	@Test
	public void testFindAll() throws Exception {
		System.out.println(ServiceFactory.getINewsServiceInstance().findAll());
	}

	@Test
	public void testFindById() throws Exception {
		System.out.println(ServiceFactory.getINewsServiceInstance()
				.findById(61).getTname());
	}

	@Test
	public void testInsert() throws Exception {
		News news = new News();
		news.setTitle("MyBATIS測试");
		news.setContent("MyBATIS加入測试");
		news.setTypeId(3);
		news.setPubDate(new Date());
		news.setPhoto(UUID.randomUUID().toString() + ".jpg");

		ServiceFactory.getINewsServiceInstance().insert(news);
	}

	@Test
	public void testListSplit() throws Exception {
		System.out.println(ServiceFactory.getINewsServiceInstance().list(1, 5,
				"title", ""));
	}
}