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。
读取Excel中的信息
工具类代码，Maven中引入如下两个包
代码语言：javascript复制<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
代码语言：javascript复制 /**
* 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Row
for (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
代码语言：javascript复制 /**
* 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
简单的单线程发送
代码语言：javascript复制/**
* 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
代码语言：javascript复制 /**
* 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;
}另一种方便的分配方式
代码语言：javascript复制 /**
* 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
代码语言：javascript复制 /**
* 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
代码语言：javascript复制 /**
* 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
代码语言：javascript复制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Row
for (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;
}
@Override
public 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;
}
@Override
public Long call() throws Exception {
Long startMills = System.currentTimeMillis();
for (String number : numberListByThread) {
sendMsgToPhone(number);
}
Long endMills = System.currentTimeMillis();
return endMills - startMills;
}
}
}
