package com.swift;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

public class Copy_java_To_txt {

    public static void main(String[] args) {

        /*

         * 把一个文件夹下的.java文件复制到另一个文件夹下的.txt文件

         */

        try {

            StringBuffer sb = new StringBuffer();

            BufferedReader br = new BufferedReader(

                    new InputStreamReader(new FileInputStream("e:\\neck\\test.java"), "utf-8"));

            String str;

            while ((str = br.readLine()) != null) {

                System.out.println("从文件中读取了一行...");

                sb.append(str);

                sb.append("\r\n");

            }

            System.out.println("文件读取到容器成功"+"\r\n"+sb.toString());

            String dir="e:\\apple";

            String fileName="test.txt";

            File file=new File(dir,fileName);

            if(!file.getParentFile().exists()) {

                System.out.println(file.getParentFile()+"目录不存在，即将创建...");

                file.getParentFile().mkdirs();

            }else {

                System.out.println("目录存在，不用创建...");

            }

            BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file),"utf-8"));

            bw.write(sb.toString());

            bw.flush();

        } catch (UnsupportedEncodingException e) {

            e.printStackTrace();

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}

package com.swift;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.File;

import java.io.FileFilter;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

public class Copy_java_To_txt {

    public static void main(String[] args) {

        /*

         * 把一个文件夹下的.java文件（需要搜索所有以.java结尾的文件）复制到另一个文件夹下的.txt文件（改名为.txt的文件）

         */

        File[] files = null;

        try {

            StringBuffer sb = new StringBuffer();

            File dir_source = new File("e:\\neck");

            File dir_destination = new File("e:\\apple");

            if(!dir_destination.exists()) {

                dir_destination.mkdirs();

            }

            if (dir_source.exists()) {

                System.out.println("搜索地址存在...");

                if (dir_source.isDirectory()) {

                    System.out.println("此地址是一个目录...");

                    files = dir_source.listFiles(new FileFilter() {

                        @Override

                        public boolean accept(File arg0) {

                            return arg0.getName().endsWith(".java");

                        }

                    });

                } else {

                    System.out.println("此地址不是目录...");

                }

            } else {

                System.out.println("搜索地址不存在...");

            }

            for (File f : files) {

                System.out.println(f);

                BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(f), "utf-8"));

                String str;

                while ((str = br.readLine()) != null) {

                    System.out.println("从文件中读取了一行...");

                    sb.append(str);

                    sb.append("\r\n");

                }

                System.out.println("一个 文件读取到容器成功" + "\r\n" + sb.toString());

                BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(

                        new FileOutputStream(new File(dir_destination, f.getName().replaceAll(".java", ".txt"))),

                        "utf-8"));

                bw.write(sb.toString());

                bw.flush();

                sb.delete(0, sb.length());//也可以sb.setLength(0);sb= new StringBuffer();都可以清空StringBuffer

            }

        } catch (UnsupportedEncodingException e) {

            e.printStackTrace();

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

}