如何实现一个文件到另一个文件内容的拷贝

Runtime.getRuntime().exec("copy c:/1.txt c:/2.txt");

package com.ocean.jproject.io;/*
A set of handy methods for common (text)file-related operations. Read, write, append, prepend, read from a zip, load into a Properties object, read from console. Simple but useful.
*/
import java.io.*;
import java.util.*;
import java.util.zip.*;import com.ocean.jproject.util.*;/**
Provides useful operations on files. Most of the operations are intended
only for text files.
@date: 7/6/00
@author G. Bright
**/
public class FileTool {
//_______________________________________________________________________
 /** Append a given string to the text file with the given filename.
 @param strstring to append to file
 @param filenamename of file
 **/
 public void appendToFile(String str, String filename) throws Exception {
// Open up an outputstream writer to the file, and append str to it.
 FileOutputStream stream; //provides file access
 OutputStreamWriter writer; //writes to the file
 try {
 stream = new FileOutputStream(filename, true);
 writer = new OutputStreamWriter(stream);
 writer.write(str);
 writer.close();
 stream.close();
 } //try
 catch (Exception e) {
 throw e;
 } //catch
 } //appendToFile//_______________________________________________________________________
//_______________________________________________________________________
 /** Prepend a given string to the text file with the given filename. 
 @param strstring to prepend to file
 @param filenamename of file
 **/

public void prependToFile(String str, String filename) throws Exception {
// Read the file, then prepend str to the file text and write back
// to the file.
 String newStr; //final string to be written
 try {
 newStr = str + readFile(filename);
 writeFile(newStr, filename);
 } //try
 catch (Exception e) {
 throw e;
 } //catch
 } //prependToFile//_______________________________________________________________________
//_______________________________________________________________________
 /** Read the text file with the given filename and return as a string. 
 @param filenamename of file to read
 @returnstring of text of file
 **/
 public String readFile(String filename) throws Exception {
//Read the file into a string buffer, then return as a string.
 StringBuffer buf; //the intermediary, mutable buffer
 BufferedReader breader; //reader for the template files
 //if(JDebug.DEBUG){JDebug.print("readFile:"+filename);}
 try {
 breader = new BufferedReader(new FileReader(filename)); //header
 buf = new StringBuffer();
 while (breader.ready()) {
 buf.append( (char) breader.read());
 }
 breader.close();
 } //try
 catch (Exception e) { throw e;
 } //catch
 return buf.toString();
 } //readFile//_______________________________________________________________________
//_______________________________________________________________________
 /** Read the given text file and return as a vector of lines. 
 @param filenamename of file to read
 @returnvector, in which the ith element is a string of the
 ith line of the text file.
 **/
 public List readFileToList(String filename) throws Exception {
//Read the file into a List, then return.
 BufferedReader breader; //reader for the template files
 List list; //target vector
 String line; //line from file
 list = new ArrayList();
 try {
 breader = new BufferedReader(new FileReader(filename)); //header
 while ( (line = breader.readLine()) != null) {
 list.add(line);
 }
 breader.close();
 } //try
 catch (Exception e) {
 throw e;
 } //catch
 return list;
 } //readFileToVector//_______________________________________________________________________
//_______________________________________________________________________
 /** Write the given string to the file with the given filename. 
 @param strstring to write to file
 @param filenamename of file
 
 Note: The pre-existing contents of the file are completely over written.
 **/

public void writeFile(String str, String filename) throws Exception {
 //if(JDebug.DEBUG){JDebug.print("writeFile="+filename);}
 String strFilePath = filename.substring(0, filename.lastIndexOf("\\"));
 //if(JDebug.DEBUG){JDebug.print("file path="+strFilePath);}
 File filePath = new File(strFilePath);
 if (!filePath.exists()) {
 filePath.mkdirs();
 }// Open a writer to the file, then write the string.
 BufferedWriter bwriter; //writer to the file
 String fullfilepath; //path for the output file try {
 bwriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(
 filename)));
 bwriter.write(str);
 bwriter.flush();
 bwriter.close();
 } //try
 catch (Exception e) {
 if (JDebug.DEBUG) {
 JDebug.print(filename + e.toString());
 }
 throw e;
 } //catch
 } //writeFile//_______________________________________________________________________
//_______________________________________________________________________
 /** Copy a file to another location.
 @param sourcenamename of file to copy
 @param targetnamename of file to copy to
 **/
 public void copyFile(String sourcename, String targetname) throws Exception {
// Open up a reader from sourcename and a writer to targetname.
// Write each character from sourcename to targetname, then close.
 BufferedReader breader; //reader from source
 BufferedWriter bwriter; //writer to target
 try {
 breader = new BufferedReader(new FileReader(sourcename));
 bwriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(
 targetname)));
 while (breader.ready()) {
 bwriter.write(breader.read());
 }
 breader.close();
 bwriter.close();
 } //try
 catch (Exception e) {
 throw e;
 } //catch
 } //copyFile//_______________________________________________________________________
//_______________________________________________________________________
 /** Read a text file from a given zip file and return as a string.
 @param textFilenamethe zipped text file to read
 @param zipFilenamezipp file to open
 @returntext of the file
 **/
 public String readZippedFile(String textFilename, String zipFilename) throws
 Exception {
// Open a stream from the entry in the zip file for the file.
// Read the file into a string buffer, then return as a string.
 StringBuffer buf; //the intermediary, mutable buffer
 BufferedReader breader; //reader for the template files
 ZipFile zipFile; //zip file
 ZipEntry zipEntry; //entry in zip
 InputStream iStream; //input stream of file
 try {
 zipFile = new ZipFile(zipFilename);
 zipEntry = zipFile.getEntry(textFilename);
 iStream = zipFile.getInputStream(zipEntry);
 breader = new BufferedReader(new InputStreamReader(iStream));
 buf = new StringBuffer();
 while (breader.ready()) {
 buf.append( (char) breader.read());
 }
 breader.close();
 } //try
 catch (Exception e) {
 throw e;
 } //catch
 return buf.toString();
 } //readZippedFile//_______________________________________________________________________
//______________________________________________________________
 /** Read a line from System.in. (block) 
 @return input read from console.
 **/
 public String readConsole() throws Exception {
// Create a buffered reader with System.in, then
// read a line from it.
 BufferedReader breader;
 breader = new BufferedReader(new InputStreamReader(System.in));
 return breader.readLine();
 } //readConsole//______________________________________________________________
//______________________________________________________________
 /** Return a properties object loaded from the given file. 
 @parampropsFilename of props file to load
 @return properties object from file
 */
 public Properties loadProperties(String propsFile) throws Exception {
// Open up an input stream from the file, then read it into
// a properties hashtable and return.
 FileInputStream instream; //the input stream
 Properties props; //props object
 instream = null;
 props = new Properties();
 try {
 instream = new FileInputStream(propsFile);
 props.load(instream);
 } //try
 finally {
 try {
 instream.close();
 } //try
 catch (Exception e1) {}
 } //finally
 return props;
 } //loadProperties
//______________________________________________________________
} //FileTool

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如何实现一个文件到另一个文件内容的拷贝

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