java按行读取文件，解决断电读大文件的问题。
1.前言。
要保存当前读的记录，可以用java的类LineNumberReader.里面有getLineNumber()方法可以获得行数。
2.例子。
package com.redis;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.LineNumberReader;public class Ex7 {public void dataReader(String nameFile, int start, int finish) {if (start > finish) {System.out.println("Error start or finish!");return;}InputStream inputStream = null;LineNumberReader reader = null;try {inputStream = new FileInputStream(new File(nameFile));reader = new LineNumberReader(new InputStreamReader(inputStream));int lines = getTotalLines(new File(nameFile));if (start < 0 || finish < 0 || finish > lines || start > lines) {System.out.println("Line not found!");return;}String line = reader.readLine(); lines = 0; while (line != null) { lines++; if(lines >= start && lines <= finish){ //处理你读到的内容 System.out.println(line); //记录当前行数 System.out.println("读到第:"+reader.getLineNumber()+"行"); } line = reader.readLine(); } inputStream.close();reader.close();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {System.err.println("IO Error");System.exit(0);}}private int getTotalLines(File file) throws IOException{FileReader in = new FileReader(file); LineNumberReader reader = new LineNumberReader(in); String line = reader.readLine(); int lines = 0; while (line != null) { lines++; line = reader.readLine(); } reader.close(); in.close(); return lines;}public static void main(String[] args) {//读第二行和第四行的信息。new Ex7().dataReader("c:/data.txt", 2, 4);//new Ex7().dataReader("data.txt",3,8);}}