【一】需求
查找某個指定目錄下，創建日期在指定日期之前，且開頭為指定前綴，結尾為指定類型，大小大于指定size的文件。例如：查找我本地磁盤上位于：E:\Other\Picture\私人 目錄下，創建日期在2010年1月2日之前，開頭為IMG_、DSCN，類型為JPG、GIF，且大小超過2M的圖片資源文件。
【二】簡介
1.基本功能過濾器
=============================================
①類型：DirectoryFileFilter、FileFileFilter
②大小：EmptyFileFilter、SizeFileFilter
③時間：AgeFileFilter
④名稱：NameFileFilter、PrefixFileFilter、SuffixFileFilter、RegexFileFilter、WildcardFileFilter
⑤讀寫屬性：CanReadFileFilter、CanWriteFileFilter
⑥隱藏屬性：HiddenFileFilter
2.邏輯關系過濾器
=============================================
①邏輯與：AndFileFilter
②邏輯或：OrFileFilter
③邏輯非：NotFileFilter
④永真/假：TrueFileFilter、FalseFileFilter
3.過濾器容器
=============================================
①工具類：FileFilterUtils
【三】思路
①使用遞歸方法遍歷所有目錄
②采用FileFilter定義的各種類型進行組合
具體思路通過閱讀代碼可以知道
【四】代碼
package example.io;
import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import org.apache.commons.io.DirectoryWalker;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOCase;
import org.apache.commons.io.filefilter.AgeFileFilter;
import org.apache.commons.io.filefilter.AndFileFilter;
import org.apache.commons.io.filefilter.FileFilterUtils;
import org.apache.commons.io.filefilter.IOFileFilter;
import org.apache.commons.io.filefilter.PrefixFileFilter;
import org.apache.commons.io.filefilter.SizeFileFilter;
import org.apache.commons.io.filefilter.SuffixFileFilter;
public class ImageFileFilter 
{
private PrefixFileFilter prefixF;
private SuffixFileFilter suffixF;
private AgeFileFilter ageF;
private SizeFileFilter sizeF;
public static void main(String args[]) {
ImageFileFilter filter = new ImageFileFilter();
// Set cutoff date
Calendar instance = Calendar.getInstance();
instance.set(2010, Calendar.JANUARY, 1, 23, 59, 59);
filter.setFileAge(instance.getTime(), true);
// Set prefix
List<String> prefixs = new ArrayList<String>();
prefixs.add("IMG_");
prefixs.add("DSCN");
filter.setFilePrefix(prefixs);
// Set suffix
List<String> suffixs = new ArrayList<String>();
suffixs.add(".jpg");
suffixs.add(".gif");
filter.setFileSuffix(suffixs);
// Set size
filter.setFileSize(1024 * 1024 * 2);
// Union filter conditions
File baseDir = new File("E:/Other/Picture/私人/");
IOFileFilter fullConditions = new AndFileFilter(filter.unionFilters());
filter.search(baseDir, fullConditions);
}
public void search(File baseDir, FileFilter fullConditions) {
ImageSearcher searcher = new ImageSearcher(baseDir,
(IOFileFilter) fullConditions);
Thread searchThread = new Thread(searcher);
searchThread.start();
try {
searchThread.join(); // child thread join to main thread
} catch (InterruptedException e) {
e.printStackTrace();
}
searcher.displaySearchResult();
}
// ============== Methods to construct kinds of filters ==============
public void setFilePrefix(List<String> prefix) {
prefixF = new PrefixFileFilter(prefix, IOCase.SYSTEM);
}
public void setFileSuffix(List<String> suffix) {
suffixF = new SuffixFileFilter(suffix, IOCase.SYSTEM);
}
public void setFileAge(Date cutoffDate) {
ageF = new AgeFileFilter(cutoffDate);
}
public void setFileAge(Date cutoffDate, boolean acceptOlder) {
ageF = new AgeFileFilter(cutoffDate, acceptOlder);
}
public void setFileSize(long size) {
sizeF = new SizeFileFilter(size);
}
public void setFileSize(long size, boolean acceptLarger) {
sizeF = new SizeFileFilter(size, acceptLarger);
}
private List<FileFilter> unionFilters() {
List<FileFilter> allFilters = new ArrayList<FileFilter>();
allFilters.add(prefixF);
allFilters.add(suffixF);
allFilters.add(ageF);
allFilters.add(sizeF);
return allFilters;
}
// ============ Inner class to do search task ================
class ImageSearcher extends DirectoryWalker implements Runnable {
private volatile boolean cancelled = false;
private File basePath;
private List<String> finalResult = new ArrayList<String>();
private long startTime;
private long endTime;
public ImageSearcher(File basePath, IOFileFilter filter) {
super(FileFilterUtils.directoryFileFilter(), filter, -1);
this.basePath = basePath;
}
public void run() {
filter();
}
public void filter() {
List<String> result = new ArrayList<String>();
try {
startTime = new Date().getTime();
walk(basePath, result);
} catch (IOException e) {
e.printStackTrace();
}
endTime = new Date().getTime();
finalResult = result;
}
public List<String> getResult() {
return finalResult;
}
/** *//**
* Display search result.
*/
public void displaySearchResult() {
String s = null;
System.out.println("\n=======================================");
for (int i = 0; i < finalResult.size(); i++) {
s = (String) finalResult.get(i);
System.out.println(" Image file found: " + s);
}
int size = finalResult.size();
long elapsed = endTime - startTime;
System.out.println("\nFinally found items: " + size);
System.out.println("\nTime costing(ms) on searching: " + elapsed);
System.out.println("=======================================\n");
}
protected boolean handleDirectory(File directory, int depth,
Collection results) throws IOException {
return true;
}
protected void handleFile(File file, int depth, Collection results)
throws IOException {
StringBuffer sb = new StringBuffer(file.getAbsolutePath());
sb.append("------");
sb.append(FileUtils.byteCountToDisplaySize(file.length()));
results.add(sb.toString());
}
public void cancel() {
cancelled = true;
}
protected boolean handleIsCancelled(File file, int depth,
Collection results) {
return cancelled;
}
protected void handleCancelled(File startDirectory, Collection results,
CancelException cancel) {
if (cancelled) {
cancel();
}
System.out.println("\nCancelled by external or interal thread");
finalResult = (List<String>) results;
}
}
}
這個目錄下有23個子目錄，3452張圖片
=======================================
... ...
Image file found: E:\Other\Picture\私人\2009-雕塑公園\IMG_4968.JPG------2 MB
Image file found: E:\Other\Picture\私人\2009-雕塑公園\IMG_4977.JPG------3 MB
Image file found: E:\Other\Picture\私人\2009-雕塑公園\IMG_4992.JPG------4 MB
Image file found: E:\Other\Picture\私人\2009-雕塑公園\IMG_5001.JPG------3 MB
Image file found: E:\Other\Picture\私人\2009-雕塑公園\IMG_5010.JPG------2 MB
Finally found items: 1662
Time costing(ms) on searching: 26125
=======================================
-------------------------------------------------------------
生活就像打牌，不是要抓一手好牌，而是要盡力打好一手爛牌。
posted on 2010-04-01 17:52
Paul Lin 閱讀(3172)
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