輸入輸出流?
在Java中，我們把能夠讀取一個字節序列的對象稱作一個輸入流;而我們把夠寫一個字節序列稱作一個輸出流。它們分別由抽象類?
InputStream和OutputStream類表示。因為面向字節的流不方便用來處理存儲為Unicode（每個字符使用兩個字節)的信息。所以Java?
引入了用來處理Unicode字符的類層次，這些類派生自抽象類Reader和Writer，它們用于讀寫雙字節的Unicode字符，而不是單字節字符。?
Java.io包簡介?
JDK標準幫助文檔是這樣解釋Java.io包的，通過數據流、序列和文件系統為系統提供輸入輸出。?
InputStream類和OutputStream類?
InputStream類是所有輸入數據流的父類，它是一個抽象類，定義了所有輸入數據流都具有的共通特性。?
java.io.InputStream的方法如下：?
public?abstract?read()throws?IOException?
讀取一個字節并返回該字節，如果到輸入源的末則返回-1。一個具體的輸入流類需要重載此方法，以提供?有用的功能。例如：在FileInputStream類中，該方法從一個文件讀取一個字節。?
public?int?read(byte[]?b)throws?IOException?
把數據讀入到一個字節數據中，并返回實際讀取的字節數目。如果遇到流末?則返回-1，該方法最多讀取b.length個字節。?
public?abstract?int?read(byte[]?b,int?off,int?len)throws?IOException?
把數據讀入到一個字節數組中并返回實際讀取的字節數目。如果遇到流的末尾則的返回-1。?其中參數off表示第一個字節在b中的位置，len表示讀取的最大字節數。?
public?long?skip(long?n)throws?IOException?
略過N個字節不讀取，會返回實際略過的字節數目。因為數據流中剩下的數據可能不到N?個字節那么多，所以此時返回值會小于N。?
public?int?available()throws?IOException?
read方法(包括后面要講的OutputStream類的Write方法)都能夠陰塞一個線程，直到字節被?實際讀取或寫入。這意味著如果一個流不能立即被讀或被寫?
/*?
*?Created?on?2005-3-10?
*?To?change?the?template?for?this?generated?file?go?to?
*?Window>Preferences>Java>Code?Generation>Code?and?Comments?
*/?

import?java.io.BufferedReader;?
import?java.io.File;?
import?java.io.FileReader;?
import?java.io.FileWriter;?
import?java.io.IOException;?
import?java.io.PrintWriter;?
import?java.io.FileInputStream;;?
/**?
*?@author?zhangqinglin?
*?To?change?the?template?for?this?generated?type?comment?go?to?
*?Window>Preferences>Java>Code?Generation>Code?and?Comments?
*/?
public?class?Files?
{?
public?static?void?main(String[]?args)?throws?IOException?
{?
Files?f?=?new?Files();?
//?System.out.println(f.readFile("f:\\LinkFile.java"));?
f.fileIsNull("D:\\java\\","ejb");?
//f.readLineFile("D:\\java\\","TestFile.txt");?
//?System.out.println(f.fileIsNull("f:\\","122.txt"));?
//f.readFolderByFile("F:\\Login");?//不區分大小寫
//?System.out.println(f.createAndDeleteFolder("ss","f:\\"));?
//?System.out.println(f.createAndDeleteFile("f:\\ss\\","TestFile.dat"));?
//f.createAndDeleteFolder("1","D:\\java\\");
String[]?ss?=?new?String[50];?//定義對象數組
for(int?i=0;i<ss.length;i++)?
{?
ss?=?"信息技術和互聯網(計算機軟硬件,通訊)?"+i;?
}?
f.writeFile("D:\\java\\","TestFile.txt",ss);?

}?
/**?
*?文件的寫入?
*?@param?filePath(文件路徑)?
*?@param?fileName(文件名)?
*?@param?args[]?
*?@throws?IOException?
*/?
public?void?writeFile(String?filePath,String?fileName,String[]?args)?throws?IOException?
{?
FileWriter?fw?=?new?FileWriter(filePath+fileName);?
PrintWriter?out=new?PrintWriter(fw);?
for(int?i=0;i<args.length;i++)?
{?
out.write(args);?
out.println();?
//out.flush();?
}
System.out.println("寫入成功！");?
fw.close();?
out.close();?
}?
/**?
*?文件的寫入?
*?@param?filePath(文件路徑)?
*?@param?fileName(文件名)?
*?@param?args?
*?@throws?IOException?
*/?
public?void?writeFile(String?filePath,String?fileName,String?args)?throws?IOException?
{?
FileWriter?fw?=?new?FileWriter(filePath+fileName);?
fw.write(args);?
fw.close();?
}?
/**?
*?創建與刪除文件?
*?@param?filePath?
*?@param?fileName?
*?@return?創建成功返回true?
*?@throws?IOException?
*/?
public?boolean?createAndDeleteFile(String?filePath,String?fileName)?throws?IOException?
{?
boolean?result?=?false;?
File?file?=?new?File(filePath,fileName);?
if(file.exists()){
if(file.isFile())?
{?
file.delete();?
result?=?true;?
System.out.println("文件已經刪除！");?
}?
else?
{
???System.out.println("對不起,該路徑為目錄！");?
???
}
}
else?
{?
file.createNewFile();?//jdk5.0的新方法
result?=?true;?
System.out.println("文件已經創建！");?
}?
return?result;?
}?
/**?
*?創建和刪除目錄?
*?@param?folderName?
*?@param?filePath?
*?@return?刪除成功返回true?
*/?
public?boolean?createAndDeleteFolder(String?folderName,String?filePath)?
{?
boolean?result?=?false;?
try?
{?
File?file?=?new?File(filePath+folderName);?
if(file.exists())?
{?
if(file.isDirectory()){
file.delete();?
System.out.println("目錄已經存在，已刪除!");?
result?=?true;?
}
else{
System.out.println("對不起,該路徑為文件！");?
}
}?
else?
{?
file.mkdir();?
System.out.println("目錄不存在，已經建立!");?
result?=?true;?
}?
}?
catch(Exception?ex)?
{?
result?=?false;?
System.out.println("CreateAndDeleteFolder?is?error:"+ex);?
}?
return?result;?
}?
/**?
*?輸出目錄中的所有文件及目錄名字?
*?@param?filePath?
*/?
public?void?readFolderByFile(String?filePath)
{?
File?file?=?new?File(filePath);?
File[]?tempFile?=?file.listFiles();?
for(int?i?=?0;i<tempFile.length;i++)?
{?
if(tempFile.isFile())?
{?
System.out.println("File?:?"+tempFile.getName());?
}?
if(tempFile.isDirectory())?
{?
System.out.println("Directory?:?"+tempFile.getName());?
}?
}?
}?
/**?
*?檢查文件中是否為一個空?
*?@param?filePath?
*?@param?fileName?
*?@return?為空返回true?
*?@throws?IOException?
*/?
public?boolean?fileIsNull(String?filePath,String?fileName)?throws?IOException?
{?
boolean?result?=?false;?
FileReader?fr?=?new?FileReader(filePath+fileName);?
if(fr.read()?==?-1)?
{?
result?=?true;?
System.out.println(fileName+"?文件中沒有數據!");?
}?
else?
{?
System.out.println(fileName+"?文件中有數據!");?
}?
fr.close();?
return?result;?
}?
/**?
*?讀取文件中的所有內容?
*?@param?filePath?
*?@param?fileName?
*?@throws?IOException?
*/?
public?void?readAllFile(String?filePath,String?fileName)?throws?IOException?
{?
FileReader?fr?=?new?FileReader(filePath+fileName);?
//PrintWriter?pr=new?PrintWriter(fr);
//pr.print
int?count?=?fr.read();?
while(count?!=?-1)?
{?
System.out.print((char)count);?
count?=?fr.read();?
//System.out.println();
if(count?==?13)?
{?
fr.skip(1);?
System.out.print("跳過!");?
}
}?
System.out.println();?
fr.close();?
}?
/**?
*?一行一行的讀取文件中的數據?
*?@param?filePath?
*?@param?fileName?
*?@throws?IOException?
*/?
public?void?readLineFile(String?filePath,String?fileName)?throws?IOException?
{?
FileReader?fr?=?new?FileReader(filePath+fileName);?
BufferedReader?br?=?new?BufferedReader(fr);?
String?line?=?br.readLine();?
while(line?!=?null)?
{?
System.out.println(line);?
line?=?br.readLine();?
}?
br.close();?
fr.close();?
}
}


/***************************以下是常用的文件操作方法******************************/

/**?
???? *? @see 新建目錄?
???? *? @param? folderPath? String? 如? c:/fqf?
???? *? @return? boolean?
???? */?
?? public? void? newFolder(String? folderPath)?
{?
?????? try? {?
?????????? String? filePath? =? folderPath;?
?????????? filePath? =? filePath.toString();?
?????????? java.io.File? myFilePath? =? new? java.io.File(filePath);?
?????????? if? (!myFilePath.exists())??
????????????{?
?????????????? myFilePath.mkdir();?
?????????? }?
?????? }?
?????? catch? (Exception? e)?
???????{?
?????????? System.out.println("新建目錄操作出錯");?
?????????? e.printStackTrace();?
?????? }?
?? }?
?
?? /**?
???? *? @see 新建文件?
???? *? @param? filePathAndName? String? 文件路徑及名稱? 如c:/fqf.txt?
???? *? @param? fileContent? String? 文件內容?
???? *? @return? boolean?
???? */?
?? public? void? newFile(String? filePathAndName,? String? fileContent)? {?
?
?????? try? {?
?????????? String? filePath? =? filePathAndName;?
?????????? filePath? =? filePath.toString();?
?????????? File? myFilePath? =? new? File(filePath);?
?????????? if? (!myFilePath.exists())? {?
?????????????? myFilePath.createNewFile();?
?????????? }?
?????????? FileWriter? resultFile? =? new? FileWriter(myFilePath);?
?????????? PrintWriter? myFile? =? new? PrintWriter(resultFile);?
?????????? String? strContent? =? fileContent;?
?????????? myFile.println(strContent);?
?????????? resultFile.close();?
?
?????? }?
?????? catch? (Exception? e)? {?
?????????? System.out.println("新建文件操作出錯");?
?????????? e.printStackTrace();?
?
?????? }?
?
?? }?
?
?? /**?
???? *? @see 刪除文件?
???? *? @param? filePathAndName? String? 文件路徑及名稱? 如c:/fqf.txt?
???? *? @param? fileContent? String?
???? *? @return? boolean?
???? */?
?? public? void? delFile(String? filePathAndName)? {?
?????? try? {?
?????????? String? filePath? =? filePathAndName;?
?????????? filePath? =? filePath.toString();?
?????????? java.io.File? myDelFile? =? new? java.io.File(filePath);?
?????????? myDelFile.delete();?
?????????? System.out.println(myDelFile + "\\文件存在，已刪除。");
?
?????? }?
?????? catch? (Exception? e)? {?
?????????? System.out.println("刪除文件操作出錯");?
?????????? e.printStackTrace();?
?
?????? }?
?
?? }?
?
?? /**?
???? *? @see 刪除文件夾?
???? *? @param? filePathAndName? String? 文件夾路徑及名稱? 如c:/fqf?
???? *? @param? fileContent? String?
???? *? @return? boolean?
???? */?
?? public? void? delFolder(String? folderPath)? {?
?????? try? {?
?????????? delAllFile(folderPath);? //刪除完里面所有內容?
?????????? String? filePath? =? folderPath;?
?????????? filePath? =? filePath.toString();?
?????????? java.io.File? myFilePath? =? new? java.io.File(filePath);?
?????????? myFilePath.delete();? //刪除空文件夾?
?
?????? }?
?????? catch? (Exception? e)? {?
?????????? System.out.println("刪除文件夾操作出錯");?
?????????? e.printStackTrace();?
?
?????? }?
?
?? }?
?
?? /**?
???? *? @see 刪除文件夾里面的所有文件?
???? *? @param? path? String? 文件夾路徑? 如? c:/fqf?
???? */?
?? public? void? delAllFile(String? path)? {?
?????? File? file? =? new? File(path);?
?????? if? (!file.exists())? {?
?????????? return;?
?????? }?
?????? if? (!file.isDirectory())? {?
?????????? return;?
?????? }?
?????? String[]? tempList? =? file.list();?
?????? File? temp? =? null;?
?????? for? (int? i? =? 0;? i? <? tempList.length;? i++)? {?
?????????? if? (path.endsWith(File.separator))? {?
?????????????? temp? =? new? File(path? +? tempList[i]);?
?????????? }?
?????????? else? {?
?????????????? temp? =? new? File(path? +? File.separator? +? tempList[i]);?
?????????? }?
?????????? if? (temp.isFile())? {?
?????????????? temp.delete();?
?????????? }?
?????????? if? (temp.isDirectory())? {?
?????????????? delAllFile(path+"/"+? tempList[i]);//先刪除文件夾里面的文件?
?????????????? delFolder(path+"/"+? tempList[i]);//再刪除空文件夾?
?????????? }?
?????? }?
?? }?
?
?? /**?
???? *? @see 復制單個文件?
???? *? @param? oldPath? String? 原文件路徑? 如：c:/fqf.txt?
???? *? @param? newPath? String? 復制后路徑? 如：f:/fqf.txt?
???? *? @return? boolean?
???? */?
?? public? void? copyFile(String? oldPath,? String? newPath)? {?
?????? try? {?
?????????? int? bytesum? =? 0;?
?????????? int? byteread? =? 0;?
?????????? File? oldfile? =? new? File(oldPath);?
?????????? if? (oldfile.exists())? {? //文件存在時?
?????????????? InputStream? inStream? =? new? FileInputStream(oldPath);? //讀入原文件?
?????????????? FileOutputStream? fs? =? new? FileOutputStream(newPath);?
?????????????? byte[]? buffer? =? new? byte[1444];?
?????????????? //int? length = 0;?
?????????????? while? (? (byteread? =? inStream.read(buffer))? !=? -1)? {?
?????????????????? bytesum? +=? byteread;? //字節數? 文件大小?
?????????????????? System.out.println(bytesum);?
?????????????????? fs.write(buffer,? 0,? byteread);?
?????????????? }?
?????????????? inStream.close();?
?????????? }?
?????? }?
?????? catch? (Exception? e)? {?
?????????? System.out.println("復制單個文件操作出錯");?
?????????? e.printStackTrace();?
?
?????? }?
?
?? }?
?
?? /**?
???? *? @see 復制整個文件夾內容?
???? *? @param? oldPath? String? 原文件路徑? 如：c:/fqf?
???? *? @param? newPath? String? 復制后路徑? 如：f:/fqf/ff?
???? *? @return? boolean?
???? */?
?? public? void? copyFolder(String? oldPath,? String? newPath)? {?
?
?????? try? {?
?????????? (new? File(newPath)).mkdirs();? //如果文件夾不存在? 則建立新文件夾?
?????????? File? a=new? File(oldPath);?
?????????? String[]? file=a.list();?
?????????? File? temp=null;?
?????????? for? (int? i? =? 0;? i? <? file.length;? i++)? {?
?????????????? if(oldPath.endsWith(File.separator)){?
?????????????????? temp=new? File(oldPath+file[i]);?
?????????????? }?
?????????????? else{?
?????????????????? temp=new? File(oldPath+File.separator+file[i]);?
?????????????? }?
?
?????????????? if(temp.isFile()){?
?????????????????? FileInputStream? input? =? new? FileInputStream(temp);?
?????????????????? FileOutputStream? output? =? new? FileOutputStream(newPath? +? "/"? +?
?????????????????????????? (temp.getName()).toString());?
?????????????????? byte[]? b? =? new? byte[1024? *? 5];?
?????????????????? int? len;?
?????????????????? while? (? (len? =? input.read(b))? !=? -1)? {?
?????????????????????? output.write(b,? 0,? len);?
?????????????????? }?
?????????????????? output.flush();?
?????????????????? output.close();?
?????????????????? input.close();?
?????????????? }?
?????????????? if(temp.isDirectory()){//如果是子文件夾?
?????????????????? copyFolder(oldPath+"/"+file[i],newPath+"/"+file[i]);?
?????????????? }?
?????????? }?
?????? }?
?????? catch? (Exception? e)? {?
?????????? System.out.println("復制整個文件夾內容操作出錯");?
?????????? e.printStackTrace();?
?
?????? }?
?
?? }?
?
?? /**?
???? *? @see 移動文件到指定目錄?
???? *? @param? oldPath? String? 如：c:/fqf.txt?
???? *? @param? newPath? String? 如：d:/fqf.txt?
???? */?
?? public? void? moveFile(String? oldPath,? String? newPath)? {?
?????? copyFile(oldPath,? newPath);?
?????? delFile(oldPath);?
?
?? }?
?
?? /**?
???? *? 移動文件到指定目錄?
???? *? @param? oldPath? String? 如：c:/fqf.txt?
???? *? @param? newPath? String? 如：d:/fqf.txt?
???? */?
?? public? void? moveFolder(String? oldPath,? String? newPath)? {?
?????? copyFolder(oldPath,? newPath);?
?????? delFolder(oldPath);?
?
?? }?
??
?? /**?
??? * @see 獲得系統根目錄絕對路徑?
??? * @return String?
??? *???
??? */
?? public String getPath(){

? String sysPath = this.getClass().getResource("/").getPath();
???? //對路徑進行修改
? sysPath = sysPath.substring(1, sysPath.length() - 16);
? return? sysPath;
???
?? }