最近学习java字符串部分，用正则表达式做了一个简单的统计单词出现次数的小程序，目前只能统计英文。
整个程序包括三个包，分别为output，run，wordcount
wordCount包
执行单词统计逻辑的工具包，使用HashMap存储某个字符串出现的次数。
setPattern用来在类外部设置不同的正则表达式,从而使用不同的分词规则（策略模式的一个变种吧），默认使用[a-zA-Z]+
getMap返回存储统计结果的map，map用来给输出器(outputProcesser)将结果输出到控制台或文件。
源代码：
package wordCount;
import java.util.*;
import java.util.Map.*;
import java.util.regex.*;
public class WordCount{
private String pattern = new String("([a-zA-Z]+)");
private HashMap map;
public void setPatterm(String p){
this.pattern = p;
}
public Map getMap(){
return this.map;
}
public void count(String str){
this.map = new HashMap();
Matcher matcher = Pattern.compile(this.pattern).matcher(str);
String key;
while ( matcher.find() ){
key = matcher.group();
if ( this.map.containsKey(key) ){
this.map.put(key, this.map.get(key) + 1);
}else {
this.map.put(key, 1);
}
}
}
}
output包
这个包包括了三个类，OutputProcesser,ConsoleOutput,FileOutput，其中OutputProcesser作为基类
OutputProcesser.java
构造器接收一个来自wordCount返回的map
processInternal()申明为抽象方法，不同的子类实现不同输出方式
output()作为外部调用的接口，接口会循环map，给processInternal提供entry，processInternal会根据提供的entry进行自己的输出
beforeOutput()在输出循环开始前调用
afterOutput()在输出循环结束后调用，这两个方法使用了模板设计模式，用于子类进行输出准备和结束操作，如输出到文件时，在循环开始前打开文件，循环结束之后关闭文件
package output;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
public abstract class OutputProcesser {
private Map map;
public OutputProcesser(Map map){
this.map = map;
}
public void output(){
if ( this.beforeOutput(this.map) ){
Iterator> iterator = this.map.entrySet().iterator();
while ( iterator.hasNext() ){
this.processInternal(iterator.next());
}
this.afterOutput(this.map);
}
}
protected boolean beforeOutput(Map map){
return true;
}
protected void afterOutput(Map map){
}
abstract protected void processInternal(Entry entry);
}
ConsoleOutput.java
package output;
import java.util.Map.Entry;
import java.util.*;
public class ConsoleOutput extends OutputProcesser{
public ConsoleOutput(Map map) {
super(map);
}
protected void processInternal(Entry entry){
System.out.println(this.logString(entry));
}
protected String logString(Entry entry){
return entry.getKey()+" : "+entry.getValue()+" times";
}
}
FileOutput.java
package output;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Map;
import java.util.Map.Entry;
public class FileOutput extends ConsoleOutput{
private String filePath = "result.txt";
private FileWriter fw;
private PrintWriter pw;
public FileOutput(Map map) {
super(map);
}
protected boolean beforeOutput(Map map){
try {
this.fw = new FileWriter(this.filePath);
this.pw = new PrintWriter(this.fw);
} catch (IOException e) {
System.out.println("IOException before process output");
}
return true;
}
protected void afterOutput(Map map){
try {
this.pw.close();
this.fw.close();
} catch (IOException e) {
System.out.println("IOException after process output");
}
}
protected void processInternal(Entry entry){
this.pw.println(this.logString(entry));
}
}
run包
该包对wordCount进行测试，并调用输出类，同时进行简单的性能测试(使用内存和耗时)。
首先会打开一个文本，并读入内存，将文本交给wordCount进行处理
package run;
import java.io.File;
import java.io.FileInputStream;
import java.util.logging.ConsoleHandler;
import org.omg.SendingContext.RunTime;
import wordCount.WordCount;
import output.*;
public class Run {
private long totalMemory = 0,time1 = 0,time2 = 0,memoryUsage = 0;
public void beginProfile(){
this.totalMemory = Runtime.getRuntime().totalMemory();
this.time1 = this.time2 = System.currentTimeMillis();
}
public void endProfile(){
this.memoryUsage = this.totalMemory -
Runtime.getRuntime().freeMemory();
this.time2 = System.currentTimeMillis();
System.out.println("memory usage:"+this.memoryUsage+" B");
System.out.println("time usage:"+(this.time2 - this.time1)+"ms");
}
public String readFromFile(String filePath){
File file = new File(filePath);
Long fLength = file.length();
byte[] content = new byte[fLength.intValue()];
try {
FileInputStream input = new FileInputStream(file);
input.read(content);
input.close();
} catch (Exception e) {
}
return new String(content);
}
public static void main(String[] args) {
Run run = new Run();
WordCount wordCount = new WordCount();
run.beginProfile();
wordCount.count(run.readFromFile("messages.txt"));
run.endProfile();
OutputProcesser out = new FileOutput(wordCount.getMap());
out.output();
}
}
下面是简单的性能测试结果
java根据标点英文分词,码迷,mamicode.com