class FileUtils {

static class CompratorByLastModified implements Comparator {

public int compare(Object o1, Object o2) {

File file1 = (File)o1;

File file2 = (File)o2;

long diff = file1.lastModified() - file2.lastModified();

if (diff > 0)

return 1;

else if (diff == 0)

return 0;

else

return -1;

}

public boolean equals(Object obj){

return true; //简单做法

}

}

static class CompratorBySize implements Comparator {

public int compare(Object o1, Object o2) {

File file1 = (File)o1;

File file2 = (File)o2;

long diff = file1.length() - file2.length();

if (diff > 0)

return 1;

else if (diff == 0)

return 0;

else

return -1;

}

public boolean equals(Object obj){

return true; //简单做法

}

}

}

Java实现集合，文件，数组排序(3)

调用的示例：

File dir = new File("C:\\temp");

File[] files = dir.listFiles();

System.out.print("before sort: ");

for (int i = 0; i< files.length; i++)

System.out.print(files[i] + " ");

System.out.println();

Arrays.sort(files);

System.out.print("sort by name: ");

for (int i = 0; i< files.length; i++)

System.out.print(files[i] + " ");

System.out.println();

Arrays.sort(files, new FileUtils.CompratorBySize());

System.out.print("sort by size: ");

for (int i = 0; i< files.length; i++)

System.out.print(files[i] + " ");

System.out.println();

Arrays.sort(files, new FileUtils.CompratorByLastModified());

System.out.print("sort by last modified: ");

for (int i = 0; i< files.length; i++)

System.out.print(files[i] + " ");

System.out.println();

自己找个目录试一下吧。用这些Java类库中的方法，一般情况下应该是不用自己写排序算法了吧？

最后附上完整代码占点版面：

import java.io.*;

import java.util.*;

public class TestSort {

public static void main(String[] args) {

sortSimpleType();

sortComparable();

sortComparator();

}

public static void sortSimpleType() {

int[] arr = {2, 3, 1,10,7,4};

System.out.print("before sort: ");

for (int i = 0; i< arr.length; i++)

System.out.print(arr[i] + " ");

System.out.println();

Arrays.sort(arr);

System.out.print("after sort: ");

for (int i = 0; i< arr.length; i++)

System.out.print(arr[i] + " ");

System.out.println();

}

public static void sortComparable() {

ArrayList list = new ArrayList();

list.add(new Programmer("张三", "C", 12000));

list.add(new Programmer("李四", "Java", 200));

list.add(new Programmer("王五", "C++", 5000));

list.add(new Programmer("钱六", "VB", 3000));

System.out.println("before sort: " + list);

Collections.sort(list);

System.out.println("after sort: " + list);

}

public static void sortComparator() {

File dir = new File("C:\\java");

File[] files = dir.listFiles();

System.out.print("before sort: ");

for (int i = 0; i< files.length; i++)

System.out

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