dbimpl2.java

springGather 在JAVA环境开发的电信运营支持系统

package org.com.gather;

import java.util.*;
import java.sql.*;
import org.com.gather.exception.*;

//切换了类,原版本事DBImpl,考虑到功能上的限制
//开发了另一个版本,DBImpl2,直接利用框架来切换类

public class DBImpl2 implements DB{
	private Properties pro = null;
	private Log log = null;
	private BackUp back = null;

	private static String key = "key";
	private static DBImpl2 instance = null;

	
	//属性由Spring注入
	private DBImpl2(Properties pro){
		this.pro = pro;
	}

	//私有的构造器,为了获取实例,要提供一个静态方法,
	//通过该方法获取实例
	public static DBImpl2 getInstance(Properties pro){
		if(instance == null){
			synchronized(key){
				if(instance == null){
					instance = new DBImpl2(pro);
				}
			}
		}
		return instance;
	}

	//有可能多个线程会同时保存数据,也就是说这个方法
	//将会出现并发问题,为了防止多个线程同时对做入库
	//操作,在这加一个同步锁.
	public synchronized void storeToDB(Collection col)throws SQLException,ClassNotFoundException,DBException{

		log.writeInfo("应该入库数量大下---"+col.size());

		if(!col.isEmpty()){
			long start = System.currentTimeMillis();
			Connection con = null;
	
			con = this.getConnection();

			log.writeDebug("成功获取连接,程序继续执行!");
			long end = System.currentTimeMillis();
			long time = (end - start)/1000;
			log.writeInfo("获取连接时长为 --->"+time);
			
			//构建一块缓存
			Collection coll = new ArrayList();
			
			//取出batchSize,每次入库量大小
			String s_size = pro.getProperty("batchSize");
			int size = new Integer(s_size).intValue();
			
			int c_size = col.size();
		
			//对入库集合进行遍历
			Iterator iter = col.iterator();
			//为了测试,这里只插入一个字段
			String sql = "insert into dt values(?)";
			PreparedStatement pstmt = null;
			try{
				pstmt = con.prepareStatement(sql);
			}catch(SQLException e){
				e.printStackTrace();
				log.writeError("解析sql语句出异常!");
				back.storeForEmpty(col);
				log.writeInfo("成功把入库数据备份!");
				System.exit(0);
			}

			while(iter.hasNext()){
				//把集合的数据存放到缓存,等到数量到了
				//batch-size指定的数量后再一次入库;
				coll.add(iter.next());

				//如果集合数据存放到缓存,则可把集合的数据
				//删除;
				iter.remove();
				
				if(coll.size() == size){
					try{
						con.setAutoCommit(false);

						Iterator it = coll.iterator();
						while(it.hasNext()){
							BIDR bidr = (BIDR)it.next();
							pstmt.setString(1,bidr.getLoginName());
							pstmt.addBatch();
						}
						pstmt.executeBatch();
						con.commit();
					}catch(SQLException e){
						log.writeError(e.getMessage());
						//把剩下没入库的数据,一并保存;
						col.addAll(coll);
						back.storeForEmpty(col);
						log.writeInfo("入库过程重出异常,成功把数据备份到文件;");
						
						try{
							con.rollback();
							log.writeInfo("入库异常,回滚!");
						}catch(SQLException ee){
							ee.printStackTrace();
							log.writeError("数据库异常,数据回滚!");
							throw new DBException(ee);
						}
						throw new DBException(e);
					}
					//把缓存清空,重新载入数据;
					coll.clear();
				}
			}


		//把剩余的数据,继续入库;
			Iterator itr = coll.iterator();
			try{
				con.setAutoCommit(false);
		 
				while(itr.hasNext()){
					BIDR br = (BIDR)itr.next();
					pstmt.setString(1,br.getLoginName());
					pstmt.addBatch();
				}
				pstmt.executeBatch();
				con.commit();
			}catch(SQLException e){
				e.printStackTrace();
				back.storeForEmpty(coll);
				log.writeInfo("成功把剩余数据备份!");
				try{
					con.rollback();
				}catch(SQLException ee){
					ee.printStackTrace();
					log.writeError("入库异常,剩余数据回滚!");
					throw new DBException(e);
				}
			}
			//清空缓存;
			coll.clear();
			//把剩余的集合数据清空; 
			col.clear();
			log.writeDebug("成功将数据插入数据库!");
		}else{
			System.out.println("入库数据量为零!");
		}
	}

	//这里每次都是拿到物理连接,可以考虑用连接池.
	public Connection getConnection()throws SQLException,ClassNotFoundException{
		Class.forName(pro.getProperty("driver"));
		Connection con = DriverManager.getConnection(pro.getProperty("url"),pro.getProperty("username"),pro.getProperty("password"));
		return con;
	}

	public void setLog(Log log){
		this.log = log;
	}

	public void setBackUpServer(BackUp back){
		this.back = back;
	}

}