java核心编程之文件过滤类FileFilter和FilenameFilter

package test;import java.io.File;import java.io.FileFilter;public class FileFilterTest implements FileFilter {      private String extension;    public FileFilterTest(String extension) {    this.extension = extension;  }  /**   *    */  @Override  public boolean accept(File pathname) {          if(pathname.isDirectory()){      return false;    }        String name = pathname.getName();    int num = name.lastIndexOf(".");    if(num == -1){      return false;    }    if(name.length()-1 == num){      return false;    } else {          return extension.equals(name.substring(num+1));    }  }      public static void main(String[] args) {        File path = new File("E://书籍//java 编程");    //获得过滤对象    FileFilterTest ft = new FileFilterTest("pdf");        File[] files = path.listFiles(ft);        for (int i = 0; i < files.length; i++) {      System.out.println(files[i].getAbsolutePath());    }       }}

package test;import java.io.File;import java.io.FilenameFilter;public class FileNameFilterTest implements FilenameFilter {    //判断图片是否格式是否是 gif  private boolean isGif(String fileName){    if(fileName.toLowerCase().endsWith(".gif")){      return true;    } else {      return false;    }      }  //判断图片是否格式是否是 jpg  private boolean isJpg(String fileName){    if(fileName.toLowerCase().endsWith(".jpg")){      return true;    } else {      return false;    }      }  //判断图片是否格式是否是 png  private boolean isPng(String fileName){    if(fileName.toLowerCase().endsWith(".png")){      return true;    } else {      return false;    }      }      @Override  public boolean accept(File dir, String name) {    return (isGif(name)||isJpg(name)||isPng(name));  }    public static void main(String[] args) {    File path = new File("C://img");    //获得过滤对象    FileNameFilterTest ft = new FileNameFilterTest();        File[] f = path.listFiles(ft);        for (int i = 0; i < f.length; i++) {      File file = f[i];            System.out.println(file.getAbsolutePath());          }  }}