Java处理大文件

        /**
         * 将文件内容全部读取到内存中
         */
        try {
            List<String> list = FileUtils.readLines(new File(fileDerec), Charsets.UTF_8);
            System.out.println(list.get(0));
        } catch (IOException e) {
            e.printStackTrace();
        }

        /**
         * java.util.*文件流处理
         */
        FileInputStream fi = null;
        Scanner sc = null;
        try {
            fi = new FileInputStream(new File(fileDerec));
            sc = new Scanner(fi, "UTF-8");
            if (sc.hasNextLine()) {
                System.out.println(sc.nextLine());
            }
        } catch (Exception e) {
        } finally {
            if (fi != null) {
                try {
                    fi.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if (sc != null) {
                sc.close();
            }
        }

        /**
         * Apache-commons-io提供的流处理
         */
        LineIterator li = null;
        try {
            li = FileUtils.lineIterator(new File(fileDerec), "UTF-8");
            if (li.hasNext()) {
                System.out.println(li.next());
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            LineIterator.closeQuietly(li);
        }