求教关于java 字节流的问题
首先说说需要的功能，
对一个文件进行解析，需要每1024个字节作为一部分，
能够实现读取文件中任意第几个1024个字节的字符串。
对于1024字节的字符串以每个字节为一个元素存储为String []。
下面是我的实现算法
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.util.ArrayList;
public class Filedecode {
public static void main(String[] args) {
//读取1.txt文件，每1024字节作为一部分，从第12个1024字节开始，一直读取8个。
readFile("D:\\1.txt",12,8);
}
public static ArrayList<String[]> readFile(String path, int startindex,
int length) {
ArrayList<String[]> list = null;
try {
File file = new File(path);
BufferedInputStream in = new BufferedInputStream(
new FileInputStream(file));
list = new ArrayList<String[]>(length);
byte[] a = new byte[1024];
String[] str = new String[1024];
int count = -1;
int com = 0;
int end = startindex + length;
while ((count = in.read(a)) != -1 && com < end) {
if (startindex == com) {
//将字节数组转字符
str = StringTool.byteTohex(a);
list.add(str);
str = null;
com++;
startindex++;
} else {
com++;
}
}
} catch (Exception e) {
e.printStackTrace();
return null;
}
return list;
}
}
用我上面的方法实现有两个问题，
1. list中存放的字符不能太多，多了就会报内存溢出，
2. 也会出现性能问题，如果要读第1000个1024字节的字符串，
需要先把前面的999个都读一遍，当要读取的文件很大时，读取速度非常慢。
//求教各位有没有更好的算法实现我的功能，本人是新人积分不多，只有60分，都给大家。
java 字节流
[解决办法]
InputStream有个skip方法，就是忽略多少个字节。不要重复读。阅读下面的API
skip
public long skip(long n)
throws IOException
Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly 0. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.
The skip method of InputStream creates a byte array and then repeatedly reads into it until n bytes have been read or the end of the stream has been reached. Subclasses are encouraged to provide a more efficient implementation of this method.
Parameters:
n - the number of bytes to be skipped.
Returns:
the actual number of bytes skipped.
Throws:
IOException - if an I/O error occurs.
[解决办法]
既然楼主的边读取边组装放List有问题，那就试试一次性把内容读到内存,在按需求处理吧
1，每次读取1024个字节，放到StringBuilder里，追加表示符"\n"、'#'什么的，你任意，只要保证不会出现在文本里的特殊字符就行
2，根据上面定义特殊字符用split分组，split的字符串数组的长度作为循环的次数
3，根据split后的每个字符串做处理，也就是用charAt得到每一个字符放入String数组
4,将每个String数组放入list
