java中常用的文件操作方法有哪些

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常用的文件的操作方法

public class FileUtility {

public static void createDir(String filePath){
 File fileDir = new File(filePath);
 try {
  if (!fileDir.exists()) {
   fileDir.mkdir();
  }
 } catch (Exception ex) {
 }
}

public FileUtility() {

}

public static void createFile(String filePath, String fileName,
  StringBuffer sb) {
 createDir(filePath);

java.io.File file = new java.io.File(filePath, fileName);
 try {
  if (file.exists() == true) {
   file = new java.io.File(filePath, fileName);
   file.delete();
  }
  file.createNewFile();
  FileOutputStream fos = new FileOutputStream(file);
  Writer out = new OutputStreamWriter(fos, "GB2312");
  out.write(sb.toString());
  out.flush();
  out.close();
  fos.close();
  out = null;
  fos = null;
 } catch (Exception ex) {
 }
}

public static void deleteFile(String filePath, String fileName)
 {
 createDir(filePath);

java.io.File file = new java.io.File(filePath, fileName);
 try {
  if (file.exists()) {
   file = new java.io.File(filePath, fileName);
   file.delete();
  }
  file = null;
 } catch (Exception ex) {
  }
}

public static void createOrClearFile(String filePath, String fileName)
  {
 createDir(filePath);
 File fileDS = new File(filePath, fileName);
 try {
  if (fileDS.exists()) {
   fileDS = new File(filePath, fileName);
   fileDS.delete();
  }
  fileDS.createNewFile();
 } catch (Exception ex) {
 }
}

public static void writeAppendFile(String filePath, String fileName,
  StringBuffer sb) {
 try {
  FileWriter fileWriter = new FileWriter(filePath + File.separator
    + fileName, true);
  PrintWriter out = new PrintWriter(fileWriter);
  out.print(sb.toString());
  out.flush();
  fileWriter.flush();
  out.close();
  fileWriter.close();
  out = null;
  fileWriter = null;
 } catch (Exception ex) {
  }
}

public static void zip(List zipList, String filePath, String zipName)
{
 BufferedInputStream origin = null;
 ZipOutputStream out = null;
 int BUFFER = 2048;
 createDir(filePath);
 try {
  File zipFile = new File(filePath, zipName);
  FileOutputStream dest = new FileOutputStream(zipFile);
  byte data[] = new byte[BUFFER];
  //针对压缩的文件打入标志位，当解压缩的时候判断是否被损坏，如果被损坏的话则不予解压缩          
  out = new ZipOutputStream(new BufferedOutputStream(dest));
  // 设置文件为压缩方式
  out.setMethod(ZipOutputStream.DEFLATED);
  int num = zipList.size();
  for (int i = 0; i < num; i++) {
   FileInputStream fi = new FileInputStream(filePath
     + File.separator + (String) zipList.get(i));
   origin = new BufferedInputStream(fi, BUFFER);
   ZipEntry entry = new ZipEntry((String) zipList.get(i));
   out.putNextEntry(entry);
   int count;
   while ((count = origin.read(data, 0, BUFFER)) != -1) {
    out.write(data, 0, count);
   }
   origin.close();
  }
  out.close();
 } catch (Exception e) {
 } finally {
  origin = null;
  out = null;
 }
}

public static void delete(List delList, String filePath)
{

try {
  for (int i = 0; i < delList.size(); i++) {
   String fileName = (String) delList.get(i);
   File f = new File(filePath, fileName);
   if (f.exists()) {
    f.delete();
   }
   fileName = null;
   f = null;
  }
 } catch (Exception e) {
  }

}

public static BufferedReader getZipReader(String filePath,
  String zipFileName, String fileName) {
 BufferedReader br = null;
 try {
  ZipFile zf = new ZipFile(filePath + File.separator + zipFileName);
  ZipEntry entry = zf.getEntry(fileName);
  br = new BufferedReader(new InputStreamReader(zf
    .getInputStream(entry)));
 } catch (Exception e) {
  }
 return br;
}

public static Document readXmlFile(File xmlFile) {
 Document doc = null;
 try {
  SAXBuilder saxBuilder = new org.jdom.input.SAXBuilder(false);
  doc = saxBuilder.build(xmlFile);
 } catch (Exception ex) {
  }
 return doc;
}

public static void saveXmlFile(String saveDir, String fileName, Document doc) {
 createDir(saveDir);

try {
  java.io.FileWriter fw = null;
  java.io.BufferedWriter bw = null;
  File file = new File(saveDir, fileName);

if (file.exists()) {
   file.delete();
  }

if (file.createNewFile()) {
   XMLOutputter xmlOut = new XMLOutputter("  ", true);

xmlOut.setEncoding("GB2312");
   fw = new java.io.FileWriter(file);
   bw = new java.io.BufferedWriter(fw);

xmlOut.output(doc, bw);

bw.flush();
   fw.flush();
   bw.close();
   fw.close();
   bw = null;
   fw = null;
  }
 } catch (Exception ex) {
  }
}

public static void createEntryFile() {
 try {
  // 创建xml文件
  Element rootElement = new Element("entry");
  Document doc = new Document(rootElement);

FileUtility.saveXmlFile(FilePath, FileName, doc);
 } catch (Exception e) {
 }
}

public void zip(List tableList, String entryFileName,
  String backupFilePath, String backupFileName){
 // 1.获取所有的压缩文件名
 List fileList = new ArrayList();
 int num = tableList.size();
 TableObject to = null;
 for (int i = 0; i < num; i++) {
  to = (TableObject) tableList.get(i);
  //只有记录大于0的表才进行输出
  if (to.getRecordnum() > 0) {
   fileList.add(to.getBackupfile());
  }
 }
 fileList.add(entryFileName);
 // 2.将所有文件进行压缩并将临时文件删除
 try {
  FileUtility.zip(fileList, backupFilePath, backupFileName);
  FileUtility.delete(fileList, backupFilePath);
 } catch (Exception e) {
  }
}

public static String checkPath(String path){
 if (!path.matches("[^*?" < > | ]{1,}")) {
 } else {
  File dir = new File(path);
  if (!dir.exists()) {
     }
  return dir.getAbsolutePath() + File.separator;
 }
}

}

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