File类的深度学习(超简易文件管理器)——《Thinking in Java》随笔028

//: MakeDirectories.java
package c10;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
*    @time:         下午7:59:23
*    @date:         2017年4月29日
*    @auther:    skyfffire
*    @version:    v0.1
*/
public class MakeDirectories {
    private final static String usage 
        = "

1.Usage:MakeDirectories path1...
"
        + "	Creates each path

"
        + "2.Usage:MakeDirectories -d path1...
"
        + "	Deletes each path

"
        + "3.Usage:MakeDirectories -r path1 path2...
"
        + "	Renames from path1 to path2

";
    
    /**
     * 使用方法
     */
    private static void usage() {
        System.out.println(usage);
        System.exit(1);
    }
    
    /**
     * 显示一个path的详细信息
     * 
     * @param f 需要显示的path
     */
    private static void fileData(File f) {
        System.out.println("

Absolute path:" + f.getAbsolutePath());
        System.out.println("Can read:" + f.canRead());
        System.out.println("Can Write:" + f.canWrite());
        System.out.println("getName:" + f.getName());
        System.out.println("getParent:" + f.getParent());
        System.out.println("getPath:" + f.getPath());
        System.out.println("length:" + f.length());        
        System.out.println("lastModified:" 
        + new SimpleDateFormat("yy-MM-dd").
        format(new Date(f.lastModified())));
        
        if (f.isFile()) {
            System.out.println("It's a file.");
        } else if (f.isDirectory()) {
            System.out.println("It's a directory.");
        }
        
        System.out.println("

");
    }
    
    /**
     * 打印当前目录下的所有path
     */
    private static void printPath() {
        System.out.println();
        
        File point = new File(".");
        
        String[] path = point.list();
        
        for (String nowString : path) {
            System.out.println(nowString);
        }
        
        System.out.println();
    }
    
    public static void main(String[] args) {
        printPath();
        
        if (args.length < 1) {
            usage();
        }
        
        // 更新path名字命令
        if (args[0].equals("-r")) {
            if (args.length != 3) {
                usage();
            } else {
                File old = new File(args[1]);
                File rname = new File(args[2]);
                
                if (old.exists() && !rname.exists()) {
                    // 更新文件名
                    old.renameTo(rname);
                } else {
                    System.out.println("rename error: "
                            + old.getName() + " to " + rname.getName());
                }
                
                // 打印信息
                fileData(old);
                fileData(rname);
            }
        } // 执行删除命令
        else if (args[0].equals("-d")) {
            for (int count = 1; count < args.length; count++) {
                File f = new File(args[count]);
                
                // 判断f是否存在
                if (f.exists()) {
                    System.out.println(f + " exists");
                    
                    System.out.println("deleting..." + f);
                    f.delete();

                    fileData(f);
                } else {
                    System.out.println(f + " path is not found.");
                }
            }
        } // 执行创建命令
        else {
            for (int count = 0; count < args.length; count++) {
                File f = new File(args[count]);
                
                f.mkdirs();
                // f.mkdir()与f.mkdirs()的区别在于
                // mkdir不能在不存在的目录创建文件夹
                
                System.out.println("created " + f);

                fileData(f);
            }
        }
        
        printPath();
    }
}

///:~

优化了原书中某些不合理的地方。运行时将参数列表置于java xxx 之后即可。