控制台程序不会写

[hujing101]

请各位大侠帮我写注释啊 我看都看不懂 先谢了

package com.itjob.io;

import java.io.*;

public class DataStreamDemo {

static String path;
static String[] cmds = null;
/**
* @param args
* @throws IOException
*/
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
InputStream in = System.in;

String cmd = "";
File f = new File(System.getProperty("user.dir"));
BufferedReader read = new BufferedReader(new InputStreamReader(in));

//StreamTokenizer st = new StreamTokenizer(new InputStreamReader(in));


path = getAbsolutePath(f);
while (!cmd.equals("exit"))
{
System.out.print(path);
cmd = read.readLine().trim();
cmds = cmd.split(" ");
if (cmds.length == 2 && cmds[0].equals("cd") && cmds[1] != null)
{

if (cmds[1].equals(".."))
{
if (f != null && f.getParentFile() != null)
f = f.getParentFile();
}
else
{
System.setProperty("user.dir", f.getAbsolutePath());
f = new File(new File(cmds[1]).getAbsolutePath());
}


path =getAbsolutePath(f.isDirectory() ? f : null);
}


if (cmds.length == 1 && cmds[0].equals("ls"))
{
for (String name : f.list())
{
System.out.print(name + " ");
}
System.out.println();
}

if (cmds.length == 3 && cmds[0].equals("cp")
&& cmds[1] != null && cmds[2] != null)
{
File src = new File(cmds[1]);
File dest = new File(cmds[2]);

if (src.exists() && dest.exists()
&& src.isFile() && dest.isDirectory())
{
BufferedReader bread = new BufferedReader(new InputStreamReader(
new FileInputStream(src)));

BufferedWriter bwrite = new BufferedWriter(new OutputStreamWriter(
new FileOutputStream(dest.getPath() + File.separator + src.getName())));

String line = null;
while ((line = bread.readLine()) != null)
{
bwrite.append(line);
bwrite.newLine();
}
bwrite.flush();

bread.close();
bwrite.close();
}
else
{
System.out.println("No such file or directory: \"" + cmds[1] + "\" and \"" + cmds[2] + "\"");
}
}
}


//random.close();
}

static String getAbsolutePath(File file)
{
if (file == null)
{
System.out.println("No such file or directory: " + cmds[1]);
return path;

}

return file.getAbsolutePath() + "> ";
}

}

[hujing101]

我想看看这个程序的注释 那位大哥帮忙注释一下

[KKK2007]

package com.itjob.io; 

import java.io.*; 

public class DataStreamDemo { 

static String path; //路径名
static String[] cmds = null; //命令列表
/** 
 * @param args 
 * @throws IOException  
 */ 
public static void main(String[] args) throws IOException { 
// TODO Auto-generated method stub 
InputStream in = System.in;// 获得控制台输入流

String cmd = ""; 
File f = new File(System.getProperty("user.dir")); //获得用户当前所在目录
BufferedReader read = new BufferedReader(new InputStreamReader(in)); 
//从控制台输入流构造一个字符缓冲区输入流
//StreamTokenizer st = new StreamTokenizer(new InputStreamReader(in)); 


path = getAbsolutePath(f); //取得用户当前所在目录的绝对路径
while (!cmd.equals("exit")) 
{ 
System.out.print(path); //向控制台输出用户当前所在目录的绝对路径
cmd = read.readLine().trim(); //从控制台读取一行用户输入的命令
cmds = cmd.split(" "); //把从控制台读取一行用户输入的命令以空格" "分离成字符串,存在数组cmds中
if (cmds.length == 2 && cmds[0].equals("cd") && cmds[1] != null) 
{ //如果用户输入的一行命令长度为2同时命令的第一个字符串是"cd"同时"cd"后面不是空的就执行下面的程序

if (cmds[1].equals("..")) 
{ //如果命令的第一个参数是"..",当前目录不是空,就用f存放父目录
if (f != null && f.getParentFile() != null) 
f = f.getParentFile(); 
} 
else //如果命令的第一个参数不是是"..",就设置系统的当前目录为参数的绝对目录
{ 
System.setProperty("user.dir", f.getAbsolutePath()); 
f = new File(new File(cmds[1]).getAbsolutePath()); 
} 

//执行完命令后,如果
path =getAbsolutePath(f.isDirectory() ? f : null); //把第一个参数表示的路径存到path里
} 


if (cmds.length == 1 && cmds[0].equals("ls"))//如果命令行字符串长度等于1,同时命令是"ls" 
{ 
for (String name : f.list()) //遍利当前目录下所有文件夹和文件,并输出名称
{ 
System.out.print(name + "  "); 
} 
System.out.println(); 
} 

if (cmds.length == 3 && cmds[0].equals("cp")  
&& cmds[1] != null && cmds[2] != null) //如果命令是"cp"同时第一个和第二个参数都不为空
{ 
File src = new File(cmds[1]); //src 为第一个参数, 源文件
File dest = new File(cmds[2]);
//dest为第二个参数,目标文件夹

if (src.exists() && dest.exists() 
&& src.isFile() && dest.isDirectory()) 
{ //如果源文件和目标文件夹都存在,就把文件复制到目标文件夹,下面的代码都是这功能

BufferedReader bread = new BufferedReader(new InputStreamReader( 
new FileInputStream(src))); 

BufferedWriter bwrite = new BufferedWriter(new OutputStreamWriter( 
new FileOutputStream(dest.getPath() + File.separator + src.getName()))); 

String line = null; 
while ((line = bread.readLine()) != null) 
{ 
bwrite.append(line); 
bwrite.newLine(); 
} 
bwrite.flush(); 

bread.close(); 
bwrite.close(); 
} 
else 
{ //如果源文件或目标文件夹不存在,就输出错无信息
System.out.println("No such file or directory: \"" + cmds[1] + "\" and \"" + cmds[2] + "\""); 
} 
} 
} 


//random.close(); 
} 

static String getAbsolutePath(File file) //静态函数,获得绝对路径
{ 
if (file == null) 
{ 
System.out.println("No such file or directory: " + cmds[1]); 
return path; 

} 

return file.getAbsolutePath() + "> "; 
} 

} 

[anqini]

// 累了....

package zhao;
import java.io.*; 

public class DataStreamDemo { 

	static String path; 
	static String[] cmds = null; 
/** 
 * @param args 
 * @throws IOException  
 */ 
	public static void main(String[] args) throws IOException { 
		// TODO Auto-generated method stub 
		InputStream in = System.in; //System.in做为一个输入流

		String cmd = ""; 
			File f = new File(System.getProperty("user.dir")); //取得当前用户程序所在目录
			BufferedReader read = new BufferedReader(new InputStreamReader(in)); //把输入流包装在BufferedReader

			//StreamTokenizer st = new StreamTokenizer(new InputStreamReader(in)); 


			path = getAbsolutePath(f); //调用此方法,参数是上面得到的用户程序所在的目录,后面加上'>'符号
			while (!cmd.equals("exit")) //假如从控制台读入的不是为"exit",就继续执行
			{ 
				System.out.print(path); //打印
				cmd = read.readLine().trim(); //从控制台读入一行字符串
				cmds = cmd.split(" "); //以" "来分割这个cmd字符串
				if (cmds.length == 2 && cmds[0].equals("cd") && cmds[1] != null) //假如cmd为 cd d:\text 这种格式的话
				{ 

					if (cmds[1].equals("..")) //假如...这个你知道吧..呵呵
					{ 
						if (f != null && f.getParentFile() != null) //假如f不为null,它的上一目录不为null,意思就是它有上一目录
							f = f.getParentFile(); //那么取它的上一目录
					} 
					else 
					{ 
						System.setProperty("user.dir", f.getAbsolutePath()); //把这个f目录的路径名字符串设置给这个值
						f = new File(new File(cmds[1]).getAbsolutePath()); //取这个 cd 后面的目录的 绝对目录,比如说,你输入 cd test,那么返回这个test的绝对路径,再构件一个File对象
					} 


					path =getAbsolutePath(f.isDirectory() ? f : null); //假如这个f对象不是文件,而是一个目录的话,就把这个f对象传进去,否则传null
				} 


				if (cmds.length == 1 && cmds[0].equals("ls")) { //逻辑判断...
	
					for (String name : f.list()) //遍历这个f对象目录底下的所有文件以及目录
					{ 
						System.out.print(name + "  "); //打印
					} 
					System.out.println(); //换行
				} 

				if (cmds.length == 3 && cmds[0].equals("cp")  //逻辑判断。。。自己知道吧
						&& cmds[1] != null && cmds[2] != null) 
				{ 
					File src = new File(cmds[1]); //创建一个file对象，好像这里涉及到linux命令，俺不懂。。。sorry
					File dest = new File(cmds[2]); 

					if (src.exists() && dest.exists() //判断这个目录或者文件存不存在
							&& src.isFile() && dest.isDirectory()) //判断src是否为文件，dest是否为目录
					{ 
						BufferedReader bread = new BufferedReader(new InputStreamReader( 
								new FileInputStream(src))); //假如src为文件的话，创建一个可以读取这个文件的输入流

						BufferedWriter bwrite = new BufferedWriter(new OutputStreamWriter( 
								new FileOutputStream(dest.getPath() + File.separator + src.getName()))); //这个dest路径+"\"+src文件名字，创建一个可以输出到这个文件的输出流

						String line = null; 
						while ((line = bread.readLine()) != null) //从控制台读入一行字符串
						{ 
							bwrite.append(line); //输出到这个bwrite输出流里
							bwrite.newLine(); //写入一个行分隔符
						} 
						bwrite.flush(); //刷新这个输出流，保证确保把写入的东西反映到此输出流文件上

						bread.close(); //关闭。。。
						bwrite.close(); 
					} 
					else 
					{ 
						System.out.println("No such file or directory: \"" + cmds[1] + "\" and \"" + cmds[2] + "\""); //....
					} 
				} 
			} 


//random.close(); 
} 

static String getAbsolutePath(File file) 
{ 
	if (file == null) 
	{ 
		System.out.println("No such file or directory: " + cmds[1]); //打印信息
		return path; 

	} 

	return file.getAbsolutePath() + "> "; //返回此抽象路径名的绝对路径名字符串.
	} 

}

[youyou1225]

师姐啊！太厉害了！

[ericSola]

mark