java IO中的乱码问题

 1 　　 //文件拆分
 2     public void SplitFileStream(String src){
 3         //数据源
 4         File file = new File(src);
 5         //总长度
 6         long len = file.length();
 7         //块大小
 8         int blockSize = 500;
 9         //块个数
10         int size = (int)Math.ceil(len*1.0/blockSize);
11 
12         //起始位置和实际大小
13         int beginPos = 0;
14         int actualSize = 0;
15         for(int i= 0;i < size;++i){
16             beginPos = i*blockSize;
17             if(i == size -1){//最后一块另外处理
18                 actualSize = (int)len;
19             }else{//剩余块数
20                 actualSize = blockSize;
21                 len-=actualSize;
22             }
23             Split(file,i,beginPos, actualSize);
24         }
25     }
26     public void Split(File srcFile,int i,long beginPos,int actualSize){
27         RandomAccessFile in = null;
28         RandomAccessFile out = null;
29         try {
30             in = new RandomAccessFile((srcFile), "r");
31             out = new RandomAccessFile(new File("D:\Test\split\"+i+"-"+srcFile.getName()), "rw");
32             in.seek(beginPos);
33             byte[] buffer = new byte[1024];
34             int length = -1;
35             while ((length = in.read(buffer, 0, buffer.length))!=-1){
36                 if (actualSize>length){
37                     out.write(buffer, 0, length);
38                     actualSize-=length;
39                 }else{
40                     out.write(buffer, 0, actualSize);
41                     break;
42                 }
43             }
44             System.out.println(i+"-->"+"已完成!");
45         } catch (FileNotFoundException e) {
46             System.out.println(i+"-->"+"有误！");
47         } catch (IOException e) {
48             System.out.println(i+"-->"+"有误！");
49         }finally {
50             if(out!=null){
51                 try {
52                     out.close();
53                 } catch (IOException e) {
54                     e.printStackTrace();
55                 }
56             }
57             if (in!=null){
58                 try {
59                     in.close();
60                 } catch (IOException e) {
61                     e.printStackTrace();
62                 }
63             }
64         }
65     }
执行上面的代码可以将某文件拆分成多个文件存储，但会出现部分正常，部分乱码的问题？？？