Java的多线程导出excel到浏览器

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小咪咪 2024-12-31 17:54:17
文章标签 Java的多线程导出excel到浏览器 java 多线程下载断点 java 下载文件写入文件 文章分类 Java 后端开发
基起原根蒂根基理：哄骗URLConnection获取要下载文件的长度、头部等相干信息，并设置响应的头部信息。并且经由过程URLConnection获取输入流，将文件分成指定的块，每一块零丁开辟一个线程完成数据的读取、写入。经由过程输入流读取下载文件的信息，然后将读取的信息用RandomAccessFile随机写入到本地文件中。同时，每个线程写入的数据都文件指针也就是写入数据的长度，须要保存在一个姑且文件中。如许当本次下载没有完成的时辰，下次下载的时辰就从这个文件中读取上一次下载的文件长度，然后持续接着上一次的地位开端下载。并且将本次下载的长度写入到这个文件中。
一、下载文件信息类、实体
封装即将下载资料的信息
DownloadInfo.java 
package com.hoo.entity;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-21 下午05:14:58
* ＠file DownloadInfo.java
* ＠package com.hoo.entity
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public class DownloadInfo {
//下载文件url private String url;
//下载文件名称 private String fileName;
//下载文件路径 private String filePath;
//分成几许段下载， 每一段用一个线程完成下载 private int splitter;
//下载文件默认保存路径 private final static String FILE_PATH = "C:/temp";
//默认分块数、线程数 private final static int SPLITTER_NUM = 5;
public DownloadInfo() {
super();
}
/***＠paramurl 下载地址*/
public DownloadInfo(String url) {
this(url， null， null， SPLITTER_NUM);
}
/***＠paramurl 下载地址url
*＠paramsplitter 分成几许段或是几许个线程下载*/
public DownloadInfo(String url， int splitter) {
this(url， null， null， splitter);
}
/***
*＠paramurl 下载地址
*＠paramfileName 文件名称
*＠paramfilePath 文件保存路径
*＠paramsplitter 分成几许段或是几许个线程下载*/
public DownloadInfo(String url， String fileName， String filePath， int splitter) {
super();
if (url == null || "".equals(url)) {
throw new RuntimeException("url is not null!");
}
this.url = url;
this.fileName = (fileName == null || "".equals(fileName)) ？ getFileName(url) : fileName;
this.filePath = (filePath == null || "".equals(filePath)) ？ FILE_PATH : filePath;
this.splitter = (splitter < 1) ？ SPLITTER_NUM : splitter;
}
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-30 下午05:00:00
*＠paramurl
*＠return*/
private String getFileName(String url) {
return url.substring(url.lastIndexOf("/") + 1， url.length());
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
if (url == null || "".equals(url)) {
throw new RuntimeException("url is not null!");
}
this.url = url;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = (fileName == null || "".equals(fileName)) ？ getFileName(url) : fileName;
}
public String getFilePath() {
return filePath;
}
public void setFilePath(String filePath) {
this.filePath = (filePath == null || "".equals(filePath)) ？ FILE_PATH : filePath;
}
public int getSplitter() {
return splitter;
}
public void setSplitter(int splitter) {
this.splitter = (splitter < 1) ？ SPLITTER_NUM : splitter;
}
＠Override
public String toString() {
return this.url + "＃" + this.fileName + "＃" + this.filePath + "＃" + this.splitter;
}
}
二、随机写入一段文件
这个类主如果完成向本地的指定文件指针出开端写入文件，并返回当前写入文件的长度(文件指针)。这个类将被线程调用，文件被分成对应的块后，将被线程调用。每个线程都将会调用这个类完成文件的随机写入。
SaveItemFile.java 
package com.hoo.download;
import java.io.IOException;
import java.io.RandomAccessFile;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-21 下午05:44:02
* ＠file SaveItemFile.java
* ＠package com.hoo.download
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public class SaveItemFile {
//存储文件 private RandomAccessFile itemFile;
public SaveItemFile() throws IOException {
this(""， 0);
}
/***＠paramname 文件路径、名称
*＠parampos 写入点地位 position
*＠throwsIOException*/
public SaveItemFile(String name， long pos) throws IOException {
itemFile = new RandomAccessFile(name， "rw");
//在指定的pos地位开端写入数据 itemFile.seek(pos);
}
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-26 下午12:21:22
*＠parambuff 缓冲数组
*＠paramstart 肇端地位
*＠paramlength 长度
*＠return*/
public synchronized int write(byte[] buff， int start， int length) {
int i = -1;
try {
itemFile.write(buff， start， length);
i = length;
} catch (IOException e) {
e.printStackTrace();
}
return i;
}
public void close() throws IOException {
if (itemFile != null) {
itemFile.close();
}
}
}
三、单个线程下载文件
这个类主如果完成单个线程的文件下载，将经由过程URLConnection读取指定url的资料信息。然后用InputStream读取文件内容，然后调用调用SaveItemFile类，向本地写入当前要读取的块的内容。
DownloadFile.java 
package com.hoo.download;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import com.hoo.util.LogUtils;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-22 下午02:55:10
* ＠file DownloadFile.java
* ＠package com.hoo.download
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public class DownloadFile extends Thread {
//下载文件url private String url;
//下载文件肇端地位 private long startPos;
//下载文件停止地位 private long endPos;
//线程id private int threadId;
//下载是否完成 private boolean isDownloadOver = false;
private SaveItemFile itemFile;
private static final int BUFF_LENGTH = 1024 * 8;
/***＠paramurl 下载文件url
*＠paramname 文件名称
*＠paramstartPos 下载文件出发点
*＠paramendPos 下载文件停止点
*＠paramthreadId 线程id
*＠throwsIOException*/
public DownloadFile(String url， String name， long startPos， long endPos， int threadId) throws IOException {
super();
this.url = url;
this.startPos = startPos;
this.endPos = endPos;
this.threadId = threadId;
//分块下载写入文件内容 this.itemFile = new SaveItemFile(name， startPos);
}
＠Override
public void run() {
while (endPos > startPos && !isDownloadOver) {
try {
URL url = new URL(this.url);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
//设置连接超不时候为10000ms conn.setConnectTimeout(10000);
//设置读取数据超不时候为10000ms conn.setReadTimeout(10000);
setHeader(conn);
String property = "bytes=" + startPos + "-";
conn.setRequestProperty("RANGE"， property);
//输出log信息 LogUtils.log("开端 " + threadId + "：" + property + endPos);
//printHeader(conn);//获取文件输入流，读取文件内容 InputStream is = conn.getInputStream();
byte[] buff = new byte[BUFF_LENGTH];
int length = -1;
LogUtils.log("＃start＃Thread: " + threadId + "， startPos: " + startPos + "， endPos: " + endPos);
while ((length = is.read(buff)) > 0 && startPos < endPos && !isDownloadOver) {
//写入文件内容，返回最后写入的长度 startPos += itemFile.write(buff， 0， length);
}
LogUtils.log("＃over＃Thread: " + threadId + "， startPos: " + startPos + "， endPos: " + endPos);
LogUtils.log("Thread " + threadId + " is execute over!");
this.isDownloadOver = true;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if (itemFile != null) {
itemFile.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
if (endPos < startPos && !isDownloadOver) {
LogUtils.log("Thread " + threadId + " startPos > endPos， not need download file !");
this.isDownloadOver = true;
}
if (endPos == startPos && !isDownloadOver) {
LogUtils.log("Thread " + threadId + " startPos = endPos， not need download file !");
this.isDownloadOver = true;
}
}
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-22 下午05:44:35
*＠paramconn HttpURLConnection*/
public static void printHeader(URLConnection conn) {
int i = 1;
while (true) {
String header = conn.getHeaderFieldKey(i);
i++;
if (header != null) {
LogUtils.info(header + ":" + conn.getHeaderField(i));
} else {
break;
}
}
}
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-28 下午05:29:43
*＠paramcon*/
public static void setHeader(URLConnection conn) {
conn.setRequestProperty("User-Agent"， "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.3) Gecko/2008092510 Ubuntu/8.04 (hardy) Firefox/3.0.3");
conn.setRequestProperty("Accept-Language"， "en-us，en;q=0.7，zh-cn;q=0.3");
conn.setRequestProperty("Accept-Encoding"， "utf-8");
conn.setRequestProperty("Accept-Charset"， "ISO-8859-1，utf-8;q=0.7，*;q=0.7");
conn.setRequestProperty("Keep-Alive"， "300");
conn.setRequestProperty("connnection"， "keep-alive");
conn.setRequestProperty("If-Modified-Since"， "Fri， 02 Jan 2009 17:00:05 GMT");
conn.setRequestProperty("If-None-Match"， "\"1261d8-4290-df64d224\"");
conn.setRequestProperty("Cache-conntrol"， "max-age=0");
conn.setRequestProperty("Referer"， "http://www.baidu.com");
}
public boolean isDownloadOver() {
return isDownloadOver;
}
public long getStartPos() {
return startPos;
}
public long getEndPos() {
return endPos;
}
}
四、分段多线程写入文件内容
这个类主如果完成读取指定url资料的内容，获取该资料的长度。然后将该资料分成指定的块数，将每块的肇端下载地位、停止下载地位，分别保存在一个数组中。每块都零丁开辟一个自力线程开端下载。在开端下载之前，须要创建一个姑且文件，写入当前下载线程的开端下载指针地位和停止下载指针地位。
BatchDownloadFile.java 
package com.hoo.download;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import com.hoo.entity.DownloadInfo;
import com.hoo.util.LogUtils;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-22 下午05:51:54
* ＠file BatchDownloadFile.java
* ＠package com.hoo.download
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public class BatchDownloadFile implements Runnable {
//下载文件信息 private DownloadInfo downloadInfo;
//一组开端下载地位 private long[] startPos;
//一组停止下载地位 private long[] endPos;
//休眠时候 private static final int SLEEP_SECONDS = 500;
//子线程下载 private DownloadFile[] fileItem;
//文件长度 private int length;
//是否第一个文件 private boolean first = true;
//是否停止下载 private boolean stop = false;
//姑且文件信息 private File tempFile;
public BatchDownloadFile(DownloadInfo downloadInfo) {
this.downloadInfo = downloadInfo;
String tempPath = this.downloadInfo.getFilePath() + File.separator + downloadInfo.getFileName() + ".position";
tempFile = new File(tempPath);
//若是存在读入点地位的文件 if (tempFile.exists()) {
first = false;
//就直接读取内容 try {
readPosInfo();
} catch (IOException e) {
e.printStackTrace();
}
} else {
//数组的长度就要分成几许段的数量 startPos = new long[downloadInfo.getSplitter()];
endPos = new long[downloadInfo.getSplitter()];
}
}
＠Override
public void run() {
//初次下载，获取下载文件长度 if (first) {
length = this.getFileSize();//获取文件长度 if (length == -1) {
LogUtils.log("file length is know!");
stop = true;
} else if (length == -2) {
LogUtils.log("read file length is error!");
stop = true;
} else if (length > 0) {
/*** eg
* start: 1， 3， 5， 7， 9
* end: 3， 5， 7， 9， length*/
for (int i = 0， len = startPos.length; i < len; i++) {
int size = i * (length / len);
startPos[i] = size;
//设置最后一个停止点的地位 if (i == len - 1) {
endPos[i] = length;
} else {
size = (i + 1) * (length / len);
endPos[i] = size;
}
LogUtils.log("start-end Position[" + i + "]: " + startPos[i] + "-" + endPos[i]);
}
} else {
LogUtils.log("get file length is error， download is stop!");
stop = true;
}
}
//子线程开端下载 if (!stop) {
//创建单线程下载对象数组 fileItem = new DownloadFile[startPos.length];//startPos.length = downloadInfo.getSplitter() for (int i = 0; i < startPos.length; i++) {
try {
//创建指定个数单线程下载对象，每个线程自力完成指定块内容的下载 fileItem[i] = new DownloadFile(
downloadInfo.getUrl()，
this.downloadInfo.getFilePath() + File.separator + downloadInfo.getFileName()，
startPos[i]， endPos[i]， i
);
fileItem[i].start();//启动线程，开端下载 LogUtils.log("Thread: " + i + "， startPos: " + startPos[i] + "， endPos: " + endPos[i]);
} catch (IOException e) {
e.printStackTrace();
}
}
//轮回写入下载文件长度信息 while (!stop) {
try {
writePosInfo();
LogUtils.log("downloading……");
Thread.sleep(SLEEP_SECONDS);
stop = true;
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
for (int i = 0; i < startPos.length; i++) {
if (!fileItem[i].isDownloadOver()) {
stop = false;
break;
}
}
}
LogUtils.info("Download task is finished!");
}
}
/*** 将写入点数据保存在姑且文件中
*＠authorhoojo
* ＠createDate 2011-9-23 下午05:25:37
*＠throwsIOException*/
private void writePosInfo() throws IOException {
DataOutputStream dos = new DataOutputStream(new FileOutputStream(tempFile));
dos.writeInt(startPos.length);
for (int i = 0; i < startPos.length; i++) {
dos.writeLong(fileItem[i].getStartPos());
dos.writeLong(fileItem[i].getEndPos());
//LogUtils.info("[" + fileItem[i].getStartPos() + "＃" + fileItem[i].getEndPos() + "]"); }
dos.close();
}
/*** function:读取写入点的地位信息
*＠authorhoojo
* ＠createDate 2011-9-23 下午05:30:29
*＠throwsIOException*/
private void readPosInfo() throws IOException {
DataInputStream dis = new DataInputStream(new FileInputStream(tempFile));
int startPosLength = dis.readInt();
startPos = new long[startPosLength];
endPos = new long[startPosLength];
for (int i = 0; i < startPosLength; i++) {
startPos[i] = dis.readLong();
endPos[i] = dis.readLong();
}
dis.close();
}
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-26 下午12:15:08
*＠return*/
private int getFileSize() {
int fileLength = -1;
try {
URL url = new URL(this.downloadInfo.getUrl());
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
DownloadFile.setHeader(conn);
int stateCode = conn.getResponseCode();
//断定http status是否为HTTP/1.1 206 Partial Content或者200 OK if (stateCode != HttpURLConnection.HTTP_OK && stateCode != HttpURLConnection.HTTP_PARTIAL) {
LogUtils.log("Error Code: " + stateCode);
return -2;
} else if (stateCode >= 400) {
LogUtils.log("Error Code: " + stateCode);
return -2;
} else {
//获取长度 fileLength = conn.getContentLength();
LogUtils.log("FileLength: " + fileLength);
}
//读取文件长度 /*for (int i = 1; ; i++) {
String header = conn.getHeaderFieldKey(i);
if (header != null) {
if ("Content-Length".equals(header)) {
fileLength = Integer.parseInt(conn.getHeaderField(i));
break;
}
} else {
break;
}
}*/
DownloadFile.printHeader(conn);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return fileLength;
}
}
五、对象类、测试类
日记对象类
LogUtils.java 
package com.hoo.util;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-21 下午05:21:27
* ＠file LogUtils.java
* ＠package com.hoo.util
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public abstract class LogUtils {
public static void log(Object message) {
System.err.println(message);
}
public static void log(String message) {
System.err.println(message);
}
public static void log(int message) {
System.err.println(message);
}
public static void info(Object message) {
System.out.println(message);
}
public static void info(String message) {
System.out.println(message);
}
public static void info(int message) {
System.out.println(message);
}
}
下载对象类
DownloadUtils.java 
package com.hoo.util;
import com.hoo.download.BatchDownloadFile;
import com.hoo.entity.DownloadInfo;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-28 下午05:22:18
* ＠file DownloadUtils.java
* ＠package com.hoo.util
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public abstract class DownloadUtils {
public static void download(String url) {
DownloadInfo bean = new DownloadInfo(url);
LogUtils.info(bean);
BatchDownloadFile down = new BatchDownloadFile(bean);
new Thread(down).start();
}
public static void download(String url， int threadNum) {
DownloadInfo bean = new DownloadInfo(url， threadNum);
LogUtils.info(bean);
BatchDownloadFile down = new BatchDownloadFile(bean);
new Thread(down).start();
}
public static void download(String url， String fileName， String filePath， int threadNum) {
DownloadInfo bean = new DownloadInfo(url， fileName， filePath， threadNum);
LogUtils.info(bean);
BatchDownloadFile down = new BatchDownloadFile(bean);
new Thread(down).start();
}
}
下载测试类
TestDownloadMain.java 
package com.hoo.test;
import com.hoo.util.DownloadUtils;
/*** function:
*＠authorhoojo
* ＠createDate 2011-9-23 下午05:49:46
* ＠file TestDownloadMain.java
* ＠package com.hoo.download
* ＠project MultiThreadDownLoad
* ＠blog* ＠email hoojo_＠126.com
*＠version1.0*/
public class TestDownloadMain {
public static void main(String[] args) {
/*DownloadInfo bean = new DownloadInfo("http://i7.meishichina.com/Health/UploadFiles/201109/2011092116224363.jpg");
System.out.println(bean);
BatchDownloadFile down = new BatchDownloadFile(bean);
new Thread(down).start();*/
//DownloadUtils.download("http://i7.meishichina.com/Health/UploadFiles/201109/2011092116224363.jpg"); DownloadUtils.download("http://mp3.baidu.com/j？j=2&url=http％3A％2F％2Fzhangmenshiting2.baidu.com％2Fdata％2Fmusic％2F1669425％2F％25E9％2599％25B7％25E5％2585％25A5％25E7％2588％25B1％25E9％2587％258C％25E9％259D％25A2.mp3％3Fxcode％3D2ff36fb70737c816553396c56deab3f1"， "aa.mp3"， "c:/temp"， 5);
}
}
多线程下载首要在第三部和第四部，其他的处所还是很好懂得。源码中供给响应的注释了，便于懂得。
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