文件拆分、合并

深藏阁楼爱情的钟 2022-05-24 07:55 225阅读 0赞

import java.io.*;
    
    
    public class IOTest {
         public static void main(String[] args){
             //拆分文件
             devide();
             //合并文件
             merge();
         }
         public static void devide(){
             //要被拆分的目标文件
             File file = new File("E:\\merge\\sxcs项目执行流程.txt");
             //文件读写流
             FileInputStream fileInputStream = null;
             FileOutputStream fileOutputStream = null;
             int num = 0;
             try {
                //获取文件的输入流,用来读取文件
                fileInputStream = new FileInputStream(file);
                //每次读的字节大小为100k
                byte[] by = new byte[100];
                while((fileInputStream.read(by)) != -1){
                    //新建存放拆分后字节的文件
                    File files = new File("E:\\merge\\sxcs项目执行流程"+num+".txt");
                    //获取输入流
                    fileOutputStream = new FileOutputStream(files);
                    //写入文件
                    fileOutputStream.write(by);
                    num++;
                    //重新初始化by数组,清空内容,如果拆分后源文件不是100的整数倍, 写入文件后会将上一个子文件的一部分写进去
                    by = new byte[100];
                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }catch (IOException e) {
                e.printStackTrace();
            }finally{
                    try {
                        if(fileOutputStream != null){
                           fileOutputStream.close();
                        }
                        if(fileInputStream != null){
                            fileInputStream.close();
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
            }
         }
         public static void merge(){
             //要合并的文件所在目录, 用来获取需要合并的文件集合
             File file = new File("E:\\merge");
             //合并后文件存放的位置
             File outFile = new File("E:\\merge\\merge.txt");
             //获取需要合并的文件集合
             File[] filelistFiles = file.listFiles();
             FileInputStream fileInputStream = null;
             FileOutputStream fileOutputStream = null;
             //循环每一个文件, 合并到一个文件重
             for(File f : filelistFiles){
                 try {
                     //存储字节大小为文件大小
                     byte[] by = new byte[(int)f.length()];
                     fileInputStream = new FileInputStream(f);
                     fileInputStream.read(by);
                     //将读取出来的文件,采用追加的方式添加到文件中
                     fileOutputStream = new FileOutputStream(outFile,true);
                     fileOutputStream.write(by);
                } catch (FileNotFoundException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }finally{
                        try {
                            if(fileInputStream != null){
                               fileInputStream.close();
                            }
                            if(fileOutputStream != null){
                                fileOutputStream.close();
                            }
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                }
                
             }
         }
    }