Home > Database > Mysql Tutorial > 找出多个文本中频率高的单词(2)

找出多个文本中频率高的单词(2)

WBOY
Release: 2016-06-07 15:32:30
Original
1313 people have browsed it

接上篇,我打算用 用concurrent包里的CountDownLatch类 去实现。 还是直接上代码吧: Main.java package com.anders.thread;import java.util.HashMap;import java.util.Map;import java.util.concurrent.CountDownLatch;import java.util.concurrent.Execut

接上篇,我打算用用concurrent包里的CountDownLatch类去实现。


还是直接上代码吧:

Main.java

package com.anders.thread;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class Main {

	public static void main(String[] args) {

		int threadNumber = Integer.parseInt(PropertiesUtil.get("ThreadNumber"));

		ExecutorService es = Executors.newFixedThreadPool(threadNumber);
		SingleThreadStatistics[] threads = new SingleThreadStatistics[threadNumber];
		try {
			CountDownLatch doneSignals = new CountDownLatch(threadNumber);

			// 这是在 文件数比线程数多的情况下,若文件比线程数少的话,加个判断就可以了
			for (int i = 0; i  map = mergeThreadMap(threads);

			display(map);

		} catch (InterruptedException e) {
			e.printStackTrace();
		} finally {
			es.shutdown();
		}

	}

	private static Map<string integer> mergeThreadMap(SingleThreadStatistics[] threads) {
		Map<string integer> map = new HashMap<string integer>();

		for (SingleThreadStatistics singleThreadStatistics : threads) {
			Map<string integer> threadMap = singleThreadStatistics.getMap();

			for (Map.Entry<string integer> entry : threadMap.entrySet()) {
				String threadWord = entry.getKey();
				Integer threadWordCount = entry.getValue();
				Integer wordCount = map.get(threadWord);

				if (wordCount == null) {
					map.put(threadWord, threadWordCount);
				} else {
					map.put(threadWord, threadWordCount + wordCount);
				}
			}
		}

		return map;
	}

	private static void display(Map<string integer> map) {

		for (Map.Entry<string integer> entry : map.entrySet()) {
			System.out.print(entry.getKey());
			System.out.println("   ," + entry.getValue());
		}

	}

}
</string></string></string></string></string></string></string>
Copy after login

SingleThreadStatistics.java
package com.anders.thread;

import java.io.File;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CountDownLatch;

public class SingleThreadStatistics implements Runnable {

	private Map<string integer> map = new HashMap<string integer>();
	private CountDownLatch doneSignals;

	public SingleThreadStatistics(CountDownLatch doneSignals) {
		this.doneSignals = doneSignals;
	}

	@Override
	public void run() {

		while (true) {
			File file = FileManager.getFile();
			if (file == null) {
				break;
			}
			FileManager.parseFile(file, map);
		}

		doneSignals.countDown();

	}

	// --------getter/setter------------

	public Map<string integer> getMap() {
		return map;
	}

}
</string></string></string>
Copy after login

FileManager.java
package com.anders.thread;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Manage files and offer single for every thread
 * 
 * @author Anders
 * 
 */
public class FileManager {

	private static List<file> fileList;
	private static int index = 0;

	static {
		String dirPath = PropertiesUtil.get("DirName");
		String path = FileManager.class.getClassLoader().getResource(dirPath).getPath();
		fileList = getFiles(path);
	}

	public synchronized static File getFile() {
		if (index == fileList.size()) {
			return null;
		}
		File file = fileList.get(index);
		index++;
		return file;
	}

	private static List<file> getFiles(String dirPath) {

		File dir = new File(dirPath);
		if (!dir.exists() || !dir.isDirectory()) {
			return Collections.emptyList();
		}

		File[] files = dir.listFiles();

		//判断 是不是  以txt结尾的文件
		Pattern pattern = Pattern.compile(PropertiesUtil.get("FileType"));
		List<file> list = new ArrayList<file>();

		for (File file : files) {
			Matcher matcher = pattern.matcher(file.getName());
			if (matcher.matches()) {
				list.add(file);
			}
		}

		return list;
	}

	//读取文件  使用的是java.nio的filechannel 和bytebuffer
	public static void parseFile(File file, Map<string integer> map) {
		FileInputStream ins = null;
		try {
			ins = new FileInputStream(file);
			FileChannel fIns = ins.getChannel();
			ByteBuffer buffer = ByteBuffer.allocate(1024);

			while (true) {
				buffer.clear();
				int r = fIns.read(buffer);
				if (r == -1) {
					break;
				}
				buffer.flip();
				buffer2word(buffer, map);
			}
			fIns.close();

		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (ins != null) {
					ins.close();
				}
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

	}

	//这个是  将读取的内容,提取出  英语字母
	private static void buffer2word(ByteBuffer buffer, Map<string integer> map) {
		StringBuilder str = new StringBuilder();
		for (int i = 0; i  map) {
		Integer count = map.get(word);
		if (null == count) {
			map.put(word, 1);
		} else {
			map.put(word, ++count);
		}
	}

	//看看是否是  英语字符
	private static boolean isEnglishChar(byte b) {
		//通过ASCLL码  判断
		if (b > 65 && b  97 && b <br>

<p><br>
</p>
config.properties<br>


<pre class="brush:php;toolbar:false">ThreadNumber=3
DirName=txt
FileType=.*.txt
Copy after login


其实我觉得最重要的代码是  FileManager里的

public synchronized static File getFile() {
		if (index == fileList.size()) {
			return null;
		}
		File file = fileList.get(index);
		index++;
		return file;
	}
Copy after login
这部分代码,因为只要  每个thread 分别得到不同的文件,就可以了。

而且还有一个很重要的一点就是  验证index是否已经读取完所有的文件  要和index++放在一个同步块里面,不然会引起线程安全问题


Related labels:
source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template