An example of Java splitting a file into multiple subfiles and merging the subfiles into the original file

Java's example of splitting a file into multiple subfiles and then merging the subfiles into the original file is as follows:

import java.io.File; 
import java.io.InputStream; 
import java.io.FileInputStream; 
import java.io.OutputStream; 
import java.io.FileOutputStream; 
import java.util.Properties; 
import java.util.Iterator; 
import java.util.TreeSet; 
import java.util.Set; 
 
public class Test 
{ 
  public static void main(String[] args) throws Exception 
  { 
    /* 
    * will 1 Three files split into multiple files , And then combine them again 1 A file  
    *  Find the file , Read in 1 a 1M the buffer In the , Then write 1 a Part In the file , This operation is looped until the file is read  
    */ 
 
    String sourceFilePath = "D:" + File.separator + "Code" + File.separator + "source" + File.separator + "031316_ The first 13 Chapter: Java Class set 】 _ Properties: Properties.wmv"; 
    int partFileLength = 1024*1024;// Specifies the size of the split subfile as 1M 
    splitFile(sourceFilePath,partFileLength);// Split the file  
    combineFile("D:" + File.separator + "Code" + File.separator + "target");// Merge the split files  
  } 
 
  public static void combineFile(String directoryPath) throws Exception 
  { 
    Properties config = new Properties(); 
    InputStream ips = null; 
    ips = new FileInputStream(new File(directoryPath + File.separator + "config.properties")); 
    config.load(ips); 
 
    Set keySet = config.keySet();// You need to keySet convert int type  
     
     
    // will keySet Iterative out , Converted to int The type of set, Sort it and store it in  
    Set<Integer> intSet = new TreeSet<Integer>(); 
    Iterator iterString = keySet.iterator(); 
    while(iterString.hasNext()) 
    { 
      String tempKey = (String)iterString.next(); 
      if("name".equals(tempKey)) 
      {} 
      else 
      { 
        int tempInt ; 
        tempInt = Integer.parseInt(tempKey); 
        intSet.add(tempInt); 
      } 
    } 
     
    Set<Integer> sortedKeySet = new TreeSet<Integer>(); 
    sortedKeySet.addAll(intSet); 
 
    OutputStream eachFileOutput = null; 
    eachFileOutput = new FileOutputStream(new File("D:" + File.separator + "Code" + File.separator + config.getProperty("name"))); 
 
    Iterator iter = sortedKeySet.iterator(); 
    while(iter.hasNext()) 
    { 
      String key = new String("" + iter.next()); 
      if(key.equals("name")) 
      {} 
      else 
      { 
        //System.out.println("debug---"); 
        String fileNumber = null; 
        String filePath = null; 
        fileNumber = key; 
        filePath = config.getProperty(fileNumber); 
 
        // Loop read file  -->  Write in turn  
 
        InputStream eachFileInput = null; 
         
        eachFileInput = new FileInputStream(new File(filePath)); 
         
        byte[] buffer = new byte[1024*1024*1];// The buffer file size is 1M 
        int len = 0; 
        while((len = eachFileInput.read(buffer,0,1024*1024*1)) != -1) 
        { 
          eachFileOutput.write(buffer,0,len); 
        } 
        eachFileInput.close(); 
      } 
    } 
 
    eachFileOutput.close(); 
  } 
 
  public static void splitFile(String sourceFilePath,int partFileLength) throws Exception  
  { 
    File sourceFile = null; 
    File targetFile = null; 
    InputStream ips = null; 
    OutputStream ops = null; 
    OutputStream configOps = null;// This file stream is used to store information about the split file, including the number and path of each child file after the split , And the name of the file before the split  
    Properties partInfo = null;//properties Used to store information about file segmentation  
    byte[] buffer = null; 
    int partNumber = 1; 
    sourceFile = new File(sourceFilePath);// Split file  
    ips = new FileInputStream(sourceFile);// Find the read source file and get the input stream  
    configOps = new FileOutputStream(new File("D:" + File.separator + "Code" // The configuration file  
      + File.separator + "target" + File.separator + "config.properties")); 
    buffer = new byte[partFileLength];// Open up cache space  
    int tempLength = 0; 
    partInfo = new Properties();//key:1 Start autonumbering  value: The file path  
 
    while((tempLength = ips.read(buffer,0,partFileLength)) != -1)  
    { 
      String targetFilePath = "D:" + File.separator + "Code"  
        + File.separator + "target" + File.separator + "part_" + (partNumber);// Split file path + The file name  
      partInfo.setProperty((partNumber++)+"",targetFilePath);// Store the relevant information in properties 
      targetFile = new File(targetFilePath); 
      ops = new FileOutputStream(targetFile);// Split file  
      ops.write(buffer,0,tempLength);// Writes the information to the shard file  
 
      ops.close();// Close the fragment file  
    } 
    partInfo.setProperty("name",sourceFile.getName());// Store source file name  
    partInfo.store(configOps,"ConfigFile");// will properties Store it in an entity file  
    ips.close();// Close the source file flow  
  } 
}