java 获取已知文件扩展名的代码

packagecom.itheima;

importjava.io.File;

/**

 * 7、 编写程序获取已知文件的扩展名. 注意: abc.txt的扩展名是txt, abc.java.txt的扩展名也是txt.

 *

 * @author 281167413@qq.com

 */

publicclassTest7 {

    publicstaticvoidmain(String[] args) {

        String srcPath ="D:/java/java.copy.doc";

        getFilenameExtension(srcPath);

    }

    // 获取指定文件的扩展名

    publicstaticvoidgetFilenameExtension(String srcPath) {

        // 将源路径转换成文件对象

        File file =newFile(srcPath);

        if(file.isFile()) {

            String name = file.getName();

            String[] exName = name.split("\.");

            System.out.println(exName[exName.length -1]);

        }else{

            System.out.println("It's not a file!");

        }

    }

    // 获取指定目录下的文件的扩展名

    publicstaticvoidgetDirFilenameExtension(String srcPath) {

        // 将源路径转换成目录对象

        File[] file = (newFile(srcPath)).listFiles();

        for(inti =0; i < file.length; i++) {

            if(file[i].isDirectory()) {

                // 准备复制的源文件夹

                srcPath = srcPath +"/"+ file[i].getName();

                getDirFilenameExtension(srcPath);

            }else{

                // 源文件

                File sourceFile = file[i];

                // 文件名字

                String name = sourceFile.getName();

                String[] exName = name.split("\.");

                System.out.println(exName[exName.length -1]);

            }

        }

    }

}