1.客户端网页下载文件， 如果文件比较大，后台要进行压缩在传输给客户端。
2.后台进行压缩以后，要保存到服务器硬盘上， 当下次请求下载，则直接传输。
3.当请求下载的压缩文件不存在，需要查询数据，生成csv，最后将多个文件进行压缩保存到服务器硬盘上。
4.多线程进行查询，单线程进行压缩。
先看一个方法：
public String accountingVerificationExport(String zipFileName) {String zipSrc = "";try {/*** 导出到本地, 然后压缩成zip,并返回zip文件地址*/zipSrc = exportToLocation(zipFileName);} catch(Exception ex) {LOGGER.info("exec accountingVerificationExport error.{}", ex.getMessage());}return zipSrc;}
方法的参数zipFileName是指定压缩之后文件名.exportLocation
/*** 启动四个线程,同步导出* @param zipFileName* @return*/private String exportToLocation(String zipFileName) {ResourceLoadUtil rlu = new ResourceLoadUtil("/hx.properties");final Properties prop = rlu.getProp();final String exportLocation = prop.getProperty("hx.export.location.href");final CountDownLatch end = new CountDownLatch(4);//子线程final String [] typeName = new String[]{"receipt","output1","output2","back"};final List<String> fileSrcs = new ArrayList<String>();// 用于存放生成的文件名称final SessionFactory sessionFactory = accountingVerificationDao.getSessionFactory();LOGGER.info("导出线程开始运行 !");for(int i = 0; i < typeName.length; i++) {final int index = i;new Thread(new Runnable() {public void run() {LOGGER.info("启动子线程{}", typeName[index]);/*** 子线程等待*/boolean participate = ConcurrentUtil.bindHibernateSessionToThread(accountingVerificationDao.getSessionFactory());String fileSrc1 = exportList(exportLocation,prop.getProperty("hx.export."+typeName[index]+".fileName"),prop.getProperty("hx.export."+typeName[index]+".sheetColumn"),prop.getProperty("hx.export."+typeName[index]+".sql"));if(!StringUtil.isEmpty(fileSrc1)) {fileSrcs.add(fileSrc1);}ConcurrentUtil.closeHibernateSessionFromThread(participate, sessionFactory); end.countDown();LOGGER.info("{} 线程结束运行.",typeName[index]);}}).start();}try {end.await();} catch (InterruptedException e) {LOGGER.info("{}",e.getMessage());}LOGGER.info("导出线程结束运行 !");String zipSrcName = "";if(!CollectionUtil.isEmpty(fileSrcs) && fileSrcs.size() > 0) {zipSrcName = exportLocation + "/" + zipFileName + ".zip";File zip = new File(zipSrcName);// 压缩文件File srcfile[] = new File[fileSrcs.size()]; for (int i = 0, n = fileSrcs.size(); i < n; i++) { srcfile[i] = new File(fileSrcs.get(i)); } FileZip.ZipFiles(srcfile, zip); }return zipSrcName;}
CountDownLatch和SessionFactory/ConcurrentUtil.bindHibernateSessionToThread
CountDownLatch: 作用是启动多个线程，主线程等待所有线程完成在执行
ConcurrentUtil.bindHibernateSessionToThread: 最多线程情况下为每个线程绑定session(只有绑定了session才可以用spring的dao bean)
/*** 导出csv文件,csv没有文件行数限制* @param exportLocation 输出到硬盘的临时地址* @param fileName 文件名* @param titles 标题* @param sql* @return*/private String exportList(String exportLocation, String fileName, String titles, String sql) {String fileSrc = exportLocation + "/" + fileName + ".csv";List<Object> list = accountingVerificationDao.queryList(sql);//查询到货接收FileOutputStream out=null;OutputStreamWriter osw=null;BufferedWriter bw=null;boolean isSucess=false;try {out = new FileOutputStream(new File(fileSrc));osw = new OutputStreamWriter(out);bw =new BufferedWriter(osw);bw.append(titles).append("\r");//标题if(!CollectionUtil.isEmpty(list) && list.size() > 0) {for(Object obj : list){String data = (String) obj;if(!StringUtil.isEmpty(data)) {data = data.replaceAll("[\\n\\r\"]", "");data = data.replaceAll("[,]", "，");data = data.replace("@#$%&", ",").trim();bw.append(data).append("\r");}}isSucess=true;}} catch (Exception e) {isSucess=false;}finally{if(bw!=null){try {bw.close();bw=null;} catch (IOException e) {e.printStackTrace();} }if(osw!=null){try {osw.close();osw=null;} catch (IOException e) {e.printStackTrace();} }if(out!=null){try {out.close();out=null;} catch (IOException e) {e.printStackTrace();} }}if(isSucess) {return fileSrc;}return null;}
import org.hibernate.FlushMode;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.springframework.orm.hibernate3.SessionFactoryUtils;import org.springframework.orm.hibernate3.SessionHolder;import org.springframework.transaction.support.TransactionSynchronizationManager;/*** HIbernate子线程中绑定session* @author Administrator**/public class ConcurrentUtil {public static boolean bindHibernateSessionToThread(SessionFactory sessionFactory) { if (TransactionSynchronizationManager.hasResource(sessionFactory)) { // Do not modify the Session: just set the participate flag. return true; } else { Session session = sessionFactory.openSession(); session.setFlushMode(FlushMode.MANUAL); SessionHolder sessionHolder = new SessionHolder(session); TransactionSynchronizationManager.bindResource(sessionFactory, sessionHolder); } return false; } public static void closeHibernateSessionFromThread(boolean participate, Object sessionFactory) { if (!participate) { SessionHolder sessionHolder = (SessionHolder)TransactionSynchronizationManager.unbindResource(sessionFactory); SessionFactoryUtils.closeSession(sessionHolder.getSession()); } } }
