Java将文件分割为多个子文件再将子文件合并成原始文件的示例

时间:2022-06-26 00:40:44

Java将文件分割为多个子文件再将子文件合并成原始文件的示例,废话不多说,代码如下:

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
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
  {
    /*
    *将一个文件分割为多个文件,然后再组合成一个文件
    * 找到文件,读入一个1M的buffer中,然后写入一个Part文件中,循环此操作直到文件读取完毕
    */
 
    String sourceFilePath = "D:" + File.separator + "Code" + File.separator + "source" + File.separator + "031316_【第13章:Java类集】_属性类:Properties.wmv";
    int partFileLength = 1024*1024;//指定分割的子文件大小为1M
    splitFile(sourceFilePath,partFileLength);//将文件分割
    combineFile("D:" + File.separator + "Code" + File.separator + "target");//将分割后的文件合并
  }
 
  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();//需要将keySet转换为int型
     
     
    //将keySet迭代出来,转换成int类型的set,排序后存储进去
    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);
 
        //循环读取文件 --> 依次写入
 
        InputStream eachFileInput = null;
         
        eachFileInput = new FileInputStream(new File(filePath));
         
        byte[] buffer = new byte[1024*1024*1];//缓冲区文件大小为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;//该文件流用于存储文件分割后的相关信息,包括分割后的每个子文件的编号和路径,以及未分割前文件名
    Properties partInfo = null;//properties用于存储文件分割的信息
    byte[] buffer = null;
    int partNumber = 1;
    sourceFile = new File(sourceFilePath);//待分割文件
    ips = new FileInputStream(sourceFile);//找到读取源文件并获取输入流
    configOps = new FileOutputStream(new File("D:" + File.separator + "Code" //配置文件
      + File.separator + "target" + File.separator + "config.properties"));
    buffer = new byte[partFileLength];//开辟缓存空间
    int tempLength = 0;
    partInfo = new Properties();//key:1开始自动编号 value:文件路径
 
    while((tempLength = ips.read(buffer,0,partFileLength)) != -1
    {
      String targetFilePath = "D:" + File.separator + "Code"
        + File.separator + "target" + File.separator + "part_" + (partNumber);//分割后的文件路径+文件名
      partInfo.setProperty((partNumber++)+"",targetFilePath);//将相关信息存储进properties
      targetFile = new File(targetFilePath);
      ops = new FileOutputStream(targetFile);//分割后文件
      ops.write(buffer,0,tempLength);//将信息写入碎片文件
 
      ops.close();//关闭碎片文件
    }
    partInfo.setProperty("name",sourceFile.getName());//存储源文件名
    partInfo.store(configOps,"ConfigFile");//将properties存储进实体文件中
    ips.close();//关闭源文件流
  }
}

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:http://blog.csdn.net/cqulyk/article/details/38471505