//拆分
public class a5Test1 {
   // 把 拆分文件 中关闭流的风格，修改成 finally 方式


    /* 找到一个大于14的文件，按照3为单位，拆分成多个子文件，并且以编号作为文件名结束。
    比如文件 111.txt，大小是14*/
   public static void splitFile(File srcFile, int eachSize){
       //写入到数组
       //复制总长度
       byte[] fileContent= new byte[(int)srcFile.length()];
       FileInputStream fis =null;
       if(srcFile.length()==0)
           throw new RuntimeException("文件为0不可拆分");
       else {
           try {

                fis = new FileInputStream(srcFile);
               fis.read(fileContent);

           }catch (IOException e){
               e.printStackTrace();
           }finally {
               try {
                   fis.close();
               }catch (Exception e){
                   e.printStackTrace();
               }
           }
       }
       //计算划分的份数
       int fileNumber;
       if (0==srcFile.length() % eachSize)
           fileNumber = (int) (srcFile.length() / eachSize);
       else
           fileNumber = (int) (srcFile.length() / eachSize)+1;
       //拆分
       for (int i = 0; i < fileNumber; i++) {
           String eachFileName = srcFile.getName() + "-" + i;
           File eachFile = new File(srcFile.getParent(), eachFileName);
           //拆分文件夹长度
           byte[] eachContent;
           FileOutputStream fos =null;
           // 从源文件的内容里，复制部分数据到子文件
           if (i != fileNumber - 1)
               eachContent = Arrays.copyOfRange(fileContent, eachSize * i, eachSize * (i + 1));
           else
               eachContent = Arrays.copyOfRange(fileContent, eachSize * i, fileContent.length);
           //写出去
           try {
                fos = new FileOutputStream(eachFile);
               fos.write(eachContent);

               System.out.println("输出子文件"+eachFile.getAbsoluteFile()+"，其大小是 "+eachFile.length()+"字节");
           }catch (IOException e){
               e.printStackTrace();
           }finally {
               try {
                   fos.close();
               }catch (IOException e){
                   e.printStackTrace();
               }
           }
       }
   }

    public static void main(String[] args) {
        splitFile(new File("D:\\javaFile\\111.txt"),3);
    }
}
//合并
public class a5Test2 {
    public static void main(String[] args) {
        //目标文件
        File mdfile = new File("D:\\javaFile\\222.txt");
        //子文件的父类
        File fuFile = new File("D:\\javaFile\\111.txt");
        File ziFile = null;
        int sum = 0;
        //用于接受子文件内容并追加内容
        List<Byte> sh = new ArrayList<>();
        // 所以创建一个空文件之前，通常都会创建父目录
        mdfile.getParentFile().mkdirs();
        try (FileInputStream fis =new FileInputStream(ziFile)) {

            while (true){
                ziFile  = new File(fuFile.getAbsoluteFile()+"-"+sum);
                sum++;
                if(!ziFile.exists())
                    break;
                //"D:\javaFile\111.txt-0"
                //输入

                byte[] zi = new byte[(int) ziFile.length()];
                fis.read(zi);
                fis.close();

                //输出
                byte[] shuzu ;
                //将子类文件输入到数组
                shuzu = Arrays.copyOfRange(zi,0,zi.length);
                //将数组遍历到集合
                for (byte b : shuzu){
                    sh.add(b);
                }
                FileOutputStream fos =new FileOutputStream(mdfile);
                //遍历结合，并将其写入目标文件mdFile
                for (byte c : sh){
                    fos.write(c);
                }
                System.out.println("111");
                System.out.println(ziFile.getAbsoluteFile());
                System.out.println(mdfile.length());
                fos.close();
            }

        } catch (FileNotFoundException e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

    }
}

package com.hui;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;
//拆分
public class Day102105 {
    //拆分文件
    public static void main(String[] args) throws IOException {
        //拆分文件
        File file = new File("D:\\ceshi\\aaa.png");
        //创建文件输入流
        FileInputStream fis=new FileInputStream(file);
        //获取分频
        FileChannel inputChannel = fis.getChannel();
        FileChannel outputChannel;
        FileOutputStream fos;
        //D:\ceshi
        String parent = file.getParent();
        //拆分字节大小
        long a=102400;
        long startPoint = 0;
        long splitNum=file.length()/a+1;
        for (long i = 1; i <=splitNum; i++) {
            String newName=file.getName()+i;
            String path=parent+"\\"+newName;
            //创建新文件
            File f=new File(path);
            if (f.exists()){
                f.mkdirs();
            }
            //文件输出流
            fos = new FileOutputStream(path);
            //获取分频
            outputChannel=fos.getChannel();
            //写入文件,startPoint 起始值,结束值,分频文件
            inputChannel.transferTo(startPoint, a, outputChannel);
            startPoint+=a;
            outputChannel.close();
            fos.close();
        }
        inputChannel.close();
        fis.close();
        file.delete();
    }

}

//合并
public class Day102106 {
    //合并文件
    public static void main(String[] args) throws IOException {
        //创建分片文件数组
        File file1 = new File("D:\\ceshi\\aaa.png1");
        File file2 = new File("D:\\ceshi\\aaa.png2");
        File file3 = new File("D:\\ceshi\\aaa.png3");
        File[]files={file1,file2,file3};
        FileInputStream fis;
        FileChannel inputChannel=null;
        String path=file1.getAbsolutePath().replace("1","");
        //创建合并文件
        File file = new File(path);
        //文件输出分频
        FileChannel outputChannel=new FileOutputStream(file).getChannel();
        long startPoint = 0;
        for (int i = 0; i < files.length; i++) {
            //文件输入流
            fis=new FileInputStream(files[i]);
            //文件输入分频
            inputChannel=fis.getChannel();
            //写入文件,起始值0,结束值(已拆分文件大小),合并分频文件
            inputChannel.transferTo(0,inputChannel.size(),outputChannel);
            inputChannel.close();
            files[i].delete();
            fis.close();
        }
        outputChannel.close();
    }

}

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;

import javax.management.RuntimeErrorException;

public class TestStream {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		int eachSize = 100 * 1024;
		File srcFile = new File("E:/pp.pptx");
		splitFile(srcFile,eachSize);
		
		File f1 = new File("E:\\pp.pptx-0");
		File f2 = new File("E:\\pp.pptx-1");
		File f3 = new File("E:\\pp.pptx-2");
		File f4 = new File("E:\\pp.pptx-3");
		File f5 = new File("E:\\pp.pptx-4");
		hefile(f1,f2,f3,f4,f5);
	}

	private static void splitFile(File srcFile,int eachSize) {
		
		if(0 == srcFile.length())
			throw new RuntimeException();
		
		byte[] fileContent = new byte[(int) srcFile.length()];
		try {
			FileInputStream fis = new FileInputStream(srcFile);
			fis.read(fileContent);
			fis.close();
		}catch (IOException e) {
			e.printStackTrace();
		}
		
		int fileNumber;
		if(0 == fileContent.length % eachSize)
            fileNumber = (int) (fileContent.length / eachSize);
        else
            fileNumber = (int) (fileContent.length / eachSize) + 1;
		
		for(int i = 0;i < fileNumber;i++) {
			String eachFileName = srcFile.getName() + "-"+ i;
			File eachFile = new File(srcFile.getParent(), eachFileName);
            byte[] eachContent;
            // 从源文件的内容里，复制部分数据到子文件
            // 除开最后一个文件，其他文件大小都是100k
            // 最后一个文件的大小是剩余的
            if (i != fileNumber - 1) // 不是最后一个
                eachContent = Arrays.copyOfRange(fileContent, eachSize * i, eachSize * (i + 1));
            else // 最后一个
                eachContent = Arrays.copyOfRange(fileContent, eachSize * i, fileContent.length);
            
            FileOutputStream fos = null;
            try {
                // 写出去
            	fos = new FileOutputStream(eachFile);
                fos.write(eachContent);
                // 记得关
                System.out.printf("输出子文件%s，其大小是 %d字节%n", eachFile.getAbsoluteFile(), eachFile.length());
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }finally {
            	if(null != fos) {
            		try {
            			fos.close();
            		}catch(IOException e) {
            			e.printStackTrace();
            		}
            	}
            }
		}
	}
	private static void hefile(File f1,File f2,File f3,File f4,File f5) {
		File file = new File("E:\\pp.pptx00");
		try (FileOutputStream fos = new FileOutputStream(file)){
			File[] f = {f1,f2,f3,f4,f5};
			for(int i = 0; i < f.length;i++) {
				byte[] b = new byte[(int)f[i].length()];
				FileInputStream fis = new FileInputStream(f[i]);
				fis.read(b);
				fis.close();
				fos.write(b);
				fos.flush();
			}
			fos.close();
			System.out.printf("最后目标文件的大小%s",file.length());
		}catch(IOException exception) {
			exception.printStackTrace();
		}
	}
}

public class IOpractice2 {
    public static void main(String[] args) {
        File file = new File("F:\\ideaProject\\javabasecod\\IOpractice" +
                "\\src\\com\\java\\demo\\IOpractice\\A.pdf");

        //将A.pdf进行拆分为大小为1000k的若干文件
        byte[] buffer = new byte[1024 * 1000];//1000k大小的字节数组
        int num = 0;//num为拆分文件个数
        if (file.length() % buffer.length == 0) {
            num = (int) (file.length() / buffer.length);
        } else {
            num = (int) (file.length() / buffer.length + 1);
        }

        FileInputStream fis = null;
        try {
            fis = new FileInputStream(file);
            for (int i = 0; i < num; i++) {
                FileOutputStream fos = new FileOutputStream("F:\\ideaProject\\javabasecod\\IOpractice" +
                        "\\src\\com\\java\\demo\\IOpractice\\file4\\" + "A" + i + ".pdf");
                int len = fis.read(buffer);
                fos.write(buffer, 0, len);
                fos.close();//关闭输出流
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (null != fis) {
                try {
                    fis.close();//关闭输入流
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }


        //讲拆分的各个文件合并为1个并能正常打开
        try (FileOutputStream fos = new FileOutputStream("F:\\ideaProject\\javabasecod\\IOpractice" +
                "\\src\\com\\java\\demo\\IOpractice\\file4\\A.pdf", true);) {
            for (int i = 0; i < num; i++) {
                FileInputStream fis1 = new FileInputStream("F:\\ideaProject\\javabasecod\\IOpractice" +
                        "\\src\\com\\java\\demo\\IOpractice\\file4\\" + "A" + i + ".pdf");

                int len = fis1.read(buffer);
                fos.write(buffer, 0, len);
                fis1.close();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}

public static String joinFilePath(String filePath,String fileName,String suffix,String extension){
        StringBuffer outFilePAth = new StringBuffer(filePath);//输出合并文件路径
        outFilePAth.append("/");
        outFilePAth.append(fileName);
        outFilePAth.append(suffix);
        outFilePAth.append(extension);
        return String.valueOf(outFilePAth);
    }

    /**
     * 按照指定大小分割文件的练习
     * ps：如果原文件包含中文内容有可能会出现乱码，因为通过流读取的是字节，而一个中文占三个字节，如果恰巧把这三个字节分割了，就会出现乱码
     * @param path
     * @param outFileSize
     */
    public static void testFile(String path, int outFileSize){
        File inFile = new File(path);//创建文件对象
        String fileAllName = inFile.getName();//获取文件名带扩展名
        String fileName = fileAllName.substring(0,fileAllName.lastIndexOf('.'));//获取文件名不带扩展
        String extension = fileAllName.substring(fileAllName.lastIndexOf('.')+1);//获取文件扩展名
        String filePath = inFile.getParent();//文件路径

        int fileSize = (int)inFile.length();//原文件大小
        int fileNumber = (int) Math.ceil(fileSize/(double)outFileSize);//计算分割文件数量（向上取整）

        byte[] inFileByte = new byte[fileSize];//申明保存原文件数据的byte数组

        //使用try-with-resources方式读取原文件数据，一次性读取完（此方式try/catch结束后自动关闭流）
        try(FileInputStream fis = new FileInputStream(inFile)){
            int byteSize = fis.read(inFileByte);//read返回（整形）读取到缓存的字节数或者-1（可以忽略返回结果）
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        String outFilePAth = joinFilePath(filePath,fileName,"-all.",extension);//输出合并文件名
        File outFile = new File(outFilePAth);//创建输出合并文件对象

        //使用try-with-resources方式保存文件数据（此方式try/catch结束后自动关闭流）
        try(FileOutputStream outFileStream = new FileOutputStream(outFile)){//合并文件输出流
            //循环按照指定大小分割原数据
            for (int i = 0;i < fileNumber;i++){
                int from = i*outFileSize;//开始位置等于次数*分割大小
                int to = i == fileNumber-1 ? inFileByte.length:(i+1)*outFileSize;//结束位置等于下一次的开始位置，也就是i+1 *分割大小；如果最后一次就是长度结尾
                byte[] fileItem = Arrays.copyOfRange(inFileByte, from, to);//按照指定分割大小复制数据
               
                String fileItemPath = joinFilePath(filePath,fileName,(i+1)+".",extension);//分割文件名
                File fileItemObj = new File(fileItemPath);//创建子文件输出对象
                try(FileOutputStream fio = new FileOutputStream(fileItemObj)){//子文件输出流
                    fio.write(fileItem);//写入分割数据
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }

                File readFileItemObj = new File(fileItemPath);//重新创建子文件读取对象
                byte[] itemFileByte = new byte[(int)readFileItemObj.length()];//申明保存数据的临时字节数组

                try(FileInputStream fis = new FileInputStream(inFile)){
                    int byteSize = fis.read(itemFileByte);//把分割的子文件写入的内容重新读取出来
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }

                outFileStream.write(itemFileByte);//把子文件的内容再次写入到新的合并文件
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

package file;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class TestClose {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		File fileInput = new File("/Users/apple/Desktop/Result");
		
		
		FileInputStream fis = null;
		try {
			fis = new FileInputStream(fileInput);
			try {
				fis.read();
				
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			try {
				fis.close();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		

		
		
	}

}