Java读取大文件java堆空间

Question

我写了这段代码:

try(BufferedReader file = new BufferedReader(new FileReader("C:\\Users\\User\\Desktop\\big50m.txt"));){
              String line;
              StringTokenizer st;

              while ((line = file.readLine()) != null){
                  st  = new StringTokenizer(line); // Separation of integers of the file line
                  while(st.hasMoreTokens())
                       numbers.add(Integer.parseInt(st.nextToken())); //Converting and adding to the list of numbers
                  }

          }
          catch(Exception e){
              System.out.println("Can't read the file...");

          }

big50m 文件有 50.000.000 个整数，我收到此运行时错误:

Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Arrays.java:3332)
    at java.lang.AbstractStringBuilder.ensureCapacityInternal(AbstractStringBuilder.java:124)
    at java.lang.AbstractStringBuilder.append(AbstractStringBuilder.java:596)
    at java.lang.StringBuffer.append(StringBuffer.java:367)
    at java.io.BufferedReader.readLine(BufferedReader.java:370)
    at java.io.BufferedReader.readLine(BufferedReader.java:389)
    at unsortedfilesapp.UnsortedFilesApp.main(UnsortedFilesApp.java:37)
C:\Users\User\AppData\Local\NetBeans\Cache\8.2\executor-snippets\run.xml:53: Java returned: 1
BUILD FAILED (total time: 5 seconds)

我认为问题出在名为line的字符串变量上。你能告诉我怎么做吗要解决这个问题 ？因为我想要快速阅读，所以我使用 StringTokenizer。

Answer 1

从文件创建一个 BufferedReader 并逐个字符read()。将数字字符放入String，然后Integer.parseInt()，跳过任何非数字字符并继续解析下一个数字，依此类推。