九乡新闻网面部轮廓整形美容医院:java 实现多线程复制功能，支持中断后继续。
来源：百度文库 编辑：九乡新闻网 时间：2024/05/02 07:53:13
CopyTask.java
Java代码 ',1)">
package copyFileTest;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
public class CopyTask implements Callable {
// 缓冲区大小
private int bufferSize = 10240;
private CountDownLatch latch;
private RandomAccessFile file = null;
private RandomAccessFile tempFile = null;
private RandomAccessFile inputFile = null;
private int id;
private long startPosition;
private long endPosition;
private long currentPosition;
public CopyTask(File file, File tmpFile, File inputFile, int id,
CountDownLatch latch, int bufferSize) {
try {
this.file = new RandomAccessFile(file, "rw");
this.tempFile = new RandomAccessFile(tmpFile, "rw");
this.inputFile = new RandomAccessFile(inputFile, "r");
} catch (FileNotFoundException e) {
e.printStackTrace();
}
this.id = id;
this.latch = latch;
this.bufferSize = bufferSize;
}
public String call() throws Exception {
try {
tempFile.seek((id - 1) * 28);
tempFile.readInt();
this.startPosition = tempFile.readLong();
this.endPosition = tempFile.readLong();
this.currentPosition = tempFile.readLong();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("Thread " + id + " begin!");
while (true) {
try {
tempFile.seek(id * 28 - 8);
if (currentPosition < endPosition) {
inputFile.seek(currentPosition);
file.seek(currentPosition);
int len = 0;
byte[] b = new byte[bufferSize];
while ((len = inputFile.read(b)) != -1) {
file.write(b, 0, len);
currentPosition += len;
tempFile.seek(id * 28 - 8);
tempFile.writeLong(currentPosition);
if (currentPosition > endPosition) {
break;
}
}
System.out.println("Thread " + id + " startPosition="
+ startPosition + ",endPosition=" + endPosition
+ ",currentPosition=" + currentPosition);
}
System.out.println("Thread " + id + " finished.");
break;
} catch (IOException e) {
e.printStackTrace();
} finally {
file.close();
tempFile.close();
inputFile.close();
}
}
latch.countDown();
return "finish";
}
}
CopyFileTest.java
Java代码 ',2)">
package copyFileTest;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class CopyFileTest {
// 线程数
private int poolSize = 10;
// 每个线程的缓冲区大小
public int bufferSize = 10240;
private int loopSize = 10000; // 每个线程循环读的次数
/**
* 复制文件
*
* @param fileSource
* 要复制的文件
* @param fileTarget
* 要复制到的文件路径
*/
public void copy(String fileSource, String fileTarget) {
long startTime = System.currentTimeMillis();
File file = null;
File tempFile = null;
File targetFile = null;
CountDownLatch latch;
ExecutorService pool = Executors.newCachedThreadPool();
long contentLength = 0;
long threadLength = 0;
try {
new File(fileTarget).mkdirs();
file = new File(fileSource);
targetFile = new File(fileTarget + File.separator + file.getName());
tempFile = new File(fileTarget + File.separator + "_temp");
// 得到content的长度
contentLength = file.length();
poolSize = this.getPoolSize(contentLength);
System.out.println("total length=" + contentLength
+ " use ThreadSize:" + poolSize);
threadLength = loopSize * bufferSize;
if (file.exists() && tempFile.exists()) {
// 如果文件已存在，根据临时文件中记载的线程数量，继续上次的任务
int tmpFileLength = (int) tempFile.length() / 28 + 1;
latch = new CountDownLatch(tmpFileLength);
for (int i = 1; i < tmpFileLength; i++) {
pool.submit(new CopyTask(targetFile, tempFile, file, i,
latch, bufferSize));
}
} else {
// 如果下载的目标文件不存在，则创建新文件
latch = new CountDownLatch(poolSize);
targetFile.createNewFile();
tempFile.createNewFile();
DataOutputStream os = new DataOutputStream(
new FileOutputStream(tempFile));
for (int i = 0; i < this.poolSize; i++) {
os.writeInt(i + 1);
os.writeLong(i * threadLength);
if (i == this.poolSize - 1) {// 最后一个线程的结束位置应为文件末端
os.writeLong(contentLength);
} else {
os.writeLong((i + 1) * threadLength);
}
os.writeLong(i * threadLength);
pool.submit(new CopyTask(targetFile, tempFile, file, i + 1,
latch, bufferSize));
}
os.close();
}
// 等待下载任务完成
latch.await();
// 删除临时文件
System.out.println("删除临时文件" + tempFile.delete());
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
pool.shutdown();
System.out.println("完成复制，所用时："
+ (System.currentTimeMillis() - startTime));
}
}
/**
* 根据总大小 缓存区与每个线程默认循环次数，判断用几个线程
*
* @param contentLength
* @return
*
*/
public int getPoolSize(long contentLength) {
int poolSize = 1;
BigDecimal contentBig = new BigDecimal(contentLength);
BigDecimal bufferBig = new BigDecimal(bufferSize);
BigDecimal loopBig = new BigDecimal(loopSize);
poolSize = contentBig.divide(bufferBig.multiply(loopBig), 0,
BigDecimal.ROUND_HALF_UP).intValue();
return poolSize;
}
public static void main(String[] args) {
String fileSource = "D:\\add.rar"; // 要复制的文件
String fileTarget = "D:\\copyTest";
new CopyFileTest().copy(fileSource, fileTarget);
}
}
Java代码 ',1)">
package copyFileTest;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
public class CopyTask implements Callable
// 缓冲区大小
private int bufferSize = 10240;
private CountDownLatch latch;
private RandomAccessFile file = null;
private RandomAccessFile tempFile = null;
private RandomAccessFile inputFile = null;
private int id;
private long startPosition;
private long endPosition;
private long currentPosition;
public CopyTask(File file, File tmpFile, File inputFile, int id,
CountDownLatch latch, int bufferSize) {
try {
this.file = new RandomAccessFile(file, "rw");
this.tempFile = new RandomAccessFile(tmpFile, "rw");
this.inputFile = new RandomAccessFile(inputFile, "r");
} catch (FileNotFoundException e) {
e.printStackTrace();
}
this.id = id;
this.latch = latch;
this.bufferSize = bufferSize;
}
public String call() throws Exception {
try {
tempFile.seek((id - 1) * 28);
tempFile.readInt();
this.startPosition = tempFile.readLong();
this.endPosition = tempFile.readLong();
this.currentPosition = tempFile.readLong();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println("Thread " + id + " begin!");
while (true) {
try {
tempFile.seek(id * 28 - 8);
if (currentPosition < endPosition) {
inputFile.seek(currentPosition);
file.seek(currentPosition);
int len = 0;
byte[] b = new byte[bufferSize];
while ((len = inputFile.read(b)) != -1) {
file.write(b, 0, len);
currentPosition += len;
tempFile.seek(id * 28 - 8);
tempFile.writeLong(currentPosition);
if (currentPosition > endPosition) {
break;
}
}
System.out.println("Thread " + id + " startPosition="
+ startPosition + ",endPosition=" + endPosition
+ ",currentPosition=" + currentPosition);
}
System.out.println("Thread " + id + " finished.");
break;
} catch (IOException e) {
e.printStackTrace();
} finally {
file.close();
tempFile.close();
inputFile.close();
}
}
latch.countDown();
return "finish";
}
}
CopyFileTest.java
Java代码 ',2)">
package copyFileTest;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class CopyFileTest {
// 线程数
private int poolSize = 10;
// 每个线程的缓冲区大小
public int bufferSize = 10240;
private int loopSize = 10000; // 每个线程循环读的次数
/**
* 复制文件
*
* @param fileSource
* 要复制的文件
* @param fileTarget
* 要复制到的文件路径
*/
public void copy(String fileSource, String fileTarget) {
long startTime = System.currentTimeMillis();
File file = null;
File tempFile = null;
File targetFile = null;
CountDownLatch latch;
ExecutorService pool = Executors.newCachedThreadPool();
long contentLength = 0;
long threadLength = 0;
try {
new File(fileTarget).mkdirs();
file = new File(fileSource);
targetFile = new File(fileTarget + File.separator + file.getName());
tempFile = new File(fileTarget + File.separator + "_temp");
// 得到content的长度
contentLength = file.length();
poolSize = this.getPoolSize(contentLength);
System.out.println("total length=" + contentLength
+ " use ThreadSize:" + poolSize);
threadLength = loopSize * bufferSize;
if (file.exists() && tempFile.exists()) {
// 如果文件已存在，根据临时文件中记载的线程数量，继续上次的任务
int tmpFileLength = (int) tempFile.length() / 28 + 1;
latch = new CountDownLatch(tmpFileLength);
for (int i = 1; i < tmpFileLength; i++) {
pool.submit(new CopyTask(targetFile, tempFile, file, i,
latch, bufferSize));
}
} else {
// 如果下载的目标文件不存在，则创建新文件
latch = new CountDownLatch(poolSize);
targetFile.createNewFile();
tempFile.createNewFile();
DataOutputStream os = new DataOutputStream(
new FileOutputStream(tempFile));
for (int i = 0; i < this.poolSize; i++) {
os.writeInt(i + 1);
os.writeLong(i * threadLength);
if (i == this.poolSize - 1) {// 最后一个线程的结束位置应为文件末端
os.writeLong(contentLength);
} else {
os.writeLong((i + 1) * threadLength);
}
os.writeLong(i * threadLength);
pool.submit(new CopyTask(targetFile, tempFile, file, i + 1,
latch, bufferSize));
}
os.close();
}
// 等待下载任务完成
latch.await();
// 删除临时文件
System.out.println("删除临时文件" + tempFile.delete());
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
pool.shutdown();
System.out.println("完成复制，所用时："
+ (System.currentTimeMillis() - startTime));
}
}
/**
* 根据总大小 缓存区与每个线程默认循环次数，判断用几个线程
*
* @param contentLength
* @return
*
*/
public int getPoolSize(long contentLength) {
int poolSize = 1;
BigDecimal contentBig = new BigDecimal(contentLength);
BigDecimal bufferBig = new BigDecimal(bufferSize);
BigDecimal loopBig = new BigDecimal(loopSize);
poolSize = contentBig.divide(bufferBig.multiply(loopBig), 0,
BigDecimal.ROUND_HALF_UP).intValue();
return poolSize;
}
public static void main(String[] args) {
String fileSource = "D:\\add.rar"; // 要复制的文件
String fileTarget = "D:\\copyTest";
new CopyFileTest().copy(fileSource, fileTarget);
}
}
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