背景

对于多线程的理解不是非常深刻，工作中用到多线程代码的机会也不多，前不久遇到了一个使用场景，通过编码实现后对于多线程的理解和应用有了更加深刻的理解。场景如下：现有给用户发送产品调研的需求，运营的同事拿来了一个Excel文件，要求给Excel里面大约六万个手机号发送调研短信。

最简单的方法就是一个循环然后单线程顺序发送，但是核心问题在于，给短信运营商发短信的接口响应时间较长，假设平均100ms的响应时间，那么单线程发送的话需要6万*0.1秒=6000秒。显然这个时间是不能接受的，运营商系统的发送接口我们是不能优化的，只得增强自己的发送和处理能力才能尽快的完成任务。

批量发短信

读取Excel中的信息

包依赖

工具类代码，Maven中引入如下两个包

<dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>3.17</version>
</dependency>
<dependency><groupId>org.apache.xmlbeans</groupId><artifactId>xmlbeans</artifactId><version>2.6.0</version>
</dependency>

读取Excel的工具类代码

/*** 读取Excel的文件信息** @param fileName*/
public static void readFromExcel(String fileName) {InputStream is = null;try {is = new FileInputStream(fileName);XSSFWorkbook workbook = new XSSFWorkbook(is);XSSFSheet sheet = workbook.getSheetAt(0);int num = 0;// 循环行Rowfor (int rowNum = 0, lastNum = sheet.getLastRowNum(); rowNum <= lastNum; rowNum++) {XSSFRow row = sheet.getRow(rowNum);String phoneNumber = getStringValueFromCell(row.getCell(0)).trim();phoneList.add(phoneNumber);}System.out.println(num);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}
}/*** 读取Excel里面Cell内容** @param cell* @return*/
private static String getStringValueFromCell(XSSFCell cell) {// 单元格内的时间格式SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");// 单元格内的数字类型DecimalFormat decimalFormat = new DecimalFormat("#.#####");// 单元格默认为空String cellValue = "";if (cell == null) {return cellValue;}// 按类型读取if (cell.getCellType() == XSSFCell.CELL_TYPE_STRING) {cellValue = cell.getStringCellValue();} else if (cell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC) {// 日期转为时间形式if (DateUtil.isCellDateFormatted(cell)) {double d = cell.getNumericCellValue();Date date = DateUtil.getJavaDate(d);cellValue = dateFormat.format(date);} else {// 其他转为数字cellValue = decimalFormat.format((cell.getNumericCellValue()));}} else if (cell.getCellType() == XSSFCell.CELL_TYPE_BLANK) {cellValue = "";} else if (cell.getCellType() == XSSFCell.CELL_TYPE_BOOLEAN) {cellValue = String.valueOf(cell.getBooleanCellValue());} else if (cell.getCellType() == XSSFCell.CELL_TYPE_ERROR) {cellValue = "";} else if (cell.getCellType() == XSSFCell.CELL_TYPE_FORMULA) {cellValue = cell.getCellFormula().toString();}return cellValue;
}　　

模拟运营商发送短信的方法

/*** 外部接口耗时长，通过多线程增强** @param userPhone*/
public void sendMsgToPhone(String userPhone) {try {Thread.sleep(SEND_COST_TIME);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("send message to : " + userPhone);
}

多线程发短信

简单的单线程发送

    /*** 单线程发送** @param phoneList* @return*/private long singleThread(List<String> phoneList) {long start = System.currentTimeMillis();/*// 直接主线程执行for (String phoneNumber : phoneList) {threadOperation.sendMsgToPhone(phoneNumber);}*/SendMsgExtendThread smet = threadOperation.new SendMsgExtendThread(phoneList);smet.start();long totalTime = System.currentTimeMillis() - start;System.out.println("单线程发送总时间：" + totalTime);return totalTime;}

对于大批量发短信的场景，如果使用单线程将全部一千个号码发送完毕的话，大约需要103132ms，可见效率低下，耗费时间较长。

多线程发送短信中的一个核心要点是，将全部手机号码拆分成多个组后，分配给每个线程进行执行。

两个线程的示例

/*** 两个线程发送** @param phoneList* @return*/
private long twoThreads(List<String> phoneList) {long start = System.currentTimeMillis();List<String> list1 = phoneList.subList(0, phoneList.size() / 2);List<String> list2 = phoneList.subList(phoneList.size() / 2, phoneList.size());SendMsgExtendThread smet = threadOperation.new SendMsgExtendThread(list1);smet.start();SendMsgExtendThread smet1 = threadOperation.new SendMsgExtendThread(list2);smet1.start();return 0;
}

另一种数据分组方式

/*** 另外一种分配方式** @param phoneList*/
private void otherThread(List<String> phoneList) {for (int threadNo = 0; threadNo < 10; threadNo++) {int numbersPerThread = 10;List<String> list = phoneList.subList(threadNo * numbersPerThread, (threadNo * numbersPerThread) + 10);SendMsgExtendThread smet = threadOperation.new SendMsgExtendThread(list);smet.start();if (list.size() < numbersPerThread) {break;}}
}

线程池发送

/*** 线程池发送** @param phoneList* @return*/
private void threadPool(List<String> phoneList) {for (int threadNo = 0; threadNo < THREAD_POOL_SIZE; threadNo++) {int numbersPerThread = 10;List<String> list = phoneList.subList(threadNo * numbersPerThread, (threadNo * numbersPerThread) + 10);threadOperation.executorService.execute(threadOperation.new SendMsgExtendThread(list));}threadOperation.executorService.shutdown();
}

使用Callable发送

/*** 多线程发送** @param phoneList* @return*/
private void multiThreadSend(List<String> phoneList) {List<Future<Long>> futures = new ArrayList<>();for (int threadNo = 0; threadNo < THREAD_POOL_SIZE; threadNo++) {int numbersPerThread = 100;List<String> list = phoneList.subList(threadNo * numbersPerThread, (threadNo * numbersPerThread) + 100);Future<Long> future = threadOperation.executorService.submit(threadOperation.new SendMsgImplCallable(list, String.valueOf(threadNo)));futures.add(future);}for (Future<Long> future : futures) {try {System.out.println(future.get());} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}threadOperation.executorService.shutdown();
}

使用多线程发送，将发送任务进行分割然后分配给每个线程执行，执行完毕需要10266ms，可见执行效率明显提升，消耗时间明显缩短。

完整代码

package com.lingyejun.tick.authenticator;import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.concurrent.*;public class ThreadOperation {// 发短信的同步等待时间private static final long SEND_COST_TIME = 100L;// 手机号文件private static final String FILE_NAME = "/Users/lingye/Downloads/phone_number.xlsx";// 手机号列表private static List<String> phoneList = new ArrayList<>();// 单例对象private static volatile ThreadOperation threadOperation;// 线程个数private static final int THREAD_POOL_SIZE = 10;// 初始化线程池private ExecutorService executorService = new ThreadPoolExecutor(THREAD_POOL_SIZE, THREAD_POOL_SIZE,0L, TimeUnit.MILLISECONDS,new LinkedBlockingQueue<Runnable>());public ThreadOperation() {// 从本地文件中读取手机号码readFromExcel(FILE_NAME);}public static void main(String[] args) {ThreadOperation threadOperation = getInstance();//threadOperation.singleThread(phoneList);threadOperation.multiThreadSend(phoneList);}/*** 单例获取对象** @return*/public static ThreadOperation getInstance() {if (threadOperation == null) {synchronized (ThreadOperation.class) {if (threadOperation == null) {threadOperation = new ThreadOperation();}}}return threadOperation;}/*** 读取Excel的文件信息** @param fileName*/public static void readFromExcel(String fileName) {InputStream is = null;try {is = new FileInputStream(fileName);XSSFWorkbook workbook = new XSSFWorkbook(is);XSSFSheet sheet = workbook.getSheetAt(0);int num = 0;// 循环行Rowfor (int rowNum = 0, lastNum = sheet.getLastRowNum(); rowNum <= lastNum; rowNum++) {XSSFRow row = sheet.getRow(rowNum);String phoneNumber = getStringValueFromCell(row.getCell(0)).trim();phoneList.add(phoneNumber);}System.out.println(num);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}/*** 读取Excel里面Cell内容** @param cell* @return*/private static String getStringValueFromCell(XSSFCell cell) {// 单元格内的时间格式SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");// 单元格内的数字类型DecimalFormat decimalFormat = new DecimalFormat("#.#####");// 单元格默认为空String cellValue = "";if (cell == null) {return cellValue;}// 按类型读取if (cell.getCellType() == XSSFCell.CELL_TYPE_STRING) {cellValue = cell.getStringCellValue();} else if (cell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC) {// 日期转为时间形式if (DateUtil.isCellDateFormatted(cell)) {double d = cell.getNumericCellValue();Date date = DateUtil.getJavaDate(d);cellValue = dateFormat.format(date);} else {// 其他转为数字cellValue = decimalFormat.format((cell.getNumericCellValue()));}} else if (cell.getCellType() == XSSFCell.CELL_TYPE_BLANK) {cellValue = "";} else if (cell.getCellType() == XSSFCell.CELL_TYPE_BOOLEAN) {cellValue = String.valueOf(cell.getBooleanCellValue());} else if (cell.getCellType() == XSSFCell.CELL_TYPE_ERROR) {cellValue = "";} else if (cell.getCellType() == XSSFCell.CELL_TYPE_FORMULA) {cellValue = cell.getCellFormula().toString();}return cellValue;}/*** 外部接口耗时长，通过多线程增强** @param userPhone*/public void sendMsgToPhone(String userPhone) {try {Thread.sleep(SEND_COST_TIME);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("send message to : " + userPhone);}/*** 单线程发送** @param phoneList* @return*/private long singleThread(List<String> phoneList) {long start = System.currentTimeMillis();/*// 直接主线程执行for (String phoneNumber : phoneList) {threadOperation.sendMsgToPhone(phoneNumber);}*/SendMsgExtendThread smet = threadOperation.new SendMsgExtendThread(phoneList);smet.start();long totalTime = System.currentTimeMillis() - start;System.out.println("单线程发送总时间：" + totalTime);return totalTime;}/*** 另外一种分配方式** @param phoneList*/private void otherThread(List<String> phoneList) {for (int threadNo = 0; threadNo < 10; threadNo++) {int numbersPerThread = 10;List<String> list = phoneList.subList(threadNo * numbersPerThread, (threadNo * numbersPerThread) + 10);SendMsgExtendThread smet = threadOperation.new SendMsgExtendThread(list);smet.start();if (list.size() < numbersPerThread) {break;}}}/*** 两个线程发送** @param phoneList* @return*/private long twoThreads(List<String> phoneList) {long start = System.currentTimeMillis();List<String> list1 = phoneList.subList(0, phoneList.size() / 2);List<String> list2 = phoneList.subList(phoneList.size() / 2, phoneList.size());SendMsgExtendThread smet = threadOperation.new SendMsgExtendThread(list1);smet.start();SendMsgExtendThread smet1 = threadOperation.new SendMsgExtendThread(list2);smet1.start();return 0;}/*** 线程池发送** @param phoneList* @return*/private void threadPool(List<String> phoneList) {for (int threadNo = 0; threadNo < THREAD_POOL_SIZE; threadNo++) {int numbersPerThread = 10;List<String> list = phoneList.subList(threadNo * numbersPerThread, (threadNo * numbersPerThread) + 10);threadOperation.executorService.execute(threadOperation.new SendMsgExtendThread(list));}threadOperation.executorService.shutdown();}/*** 多线程发送** @param phoneList* @return*/private void multiThreadSend(List<String> phoneList) {List<Future<Long>> futures = new ArrayList<>();for (int threadNo = 0; threadNo < THREAD_POOL_SIZE; threadNo++) {int numbersPerThread = 100;List<String> list = phoneList.subList(threadNo * numbersPerThread, (threadNo * numbersPerThread) + 100);Future<Long> future = threadOperation.executorService.submit(threadOperation.new SendMsgImplCallable(list, String.valueOf(threadNo)));futures.add(future);}for (Future<Long> future : futures) {try {System.out.println(future.get());} catch (InterruptedException e) {e.printStackTrace();} catch (ExecutionException e) {e.printStackTrace();}}threadOperation.executorService.shutdown();}public class SendMsgExtendThread extends Thread {private List<String> numberListByThread;public SendMsgExtendThread(List<String> numberList) {numberListByThread = numberList;}@Overridepublic void run() {long startTime = System.currentTimeMillis();for (int i = 0; i < numberListByThread.size(); i++) {System.out.print("no." + (i + 1));sendMsgToPhone(numberListByThread.get(i));}System.out.println("== single thread send " + numberListByThread.size() + "execute time:" + (System.currentTimeMillis() - startTime) + " ms");}}public class SendMsgImplCallable implements Callable<Long> {private List<String> numberListByThread;private String threadName;public SendMsgImplCallable(List<String> numberList, String threadName) {numberListByThread = numberList;this.threadName = threadName;}@Overridepublic Long call() throws Exception {Long startMills = System.currentTimeMillis();for (String number : numberListByThread) {sendMsgToPhone(number);}Long endMills = System.currentTimeMillis();return endMills - startMills;}}
}