java文本的读写

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Collection;
import java.util.Scanner;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.commons.io.LineIterator;

public class HandleTextFile {

	/**
	 * commons.io
	 * @param path
	 */
	public static void testReadFile(String path) {
        try {
            LineIterator lineIterator = FileUtils.lineIterator(new File(path), "UTF-8");
            while (lineIterator.hasNext()) {
                String line = lineIterator.nextLine();
                System.out.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
	/**
	  * commons.io
	  */
	public static void writeLines(File file, Collection lines, String lineEnding) throws IOException {
       OutputStream out = null;
       try {
       	out = new FileOutputStream(file) ;
           IOUtils.writeLines(lines, lineEnding, out, "UTF-8");
       } finally {
           IOUtils.closeQuietly(out);
       }
   }
	
	public static void testScannerReadFile(String path) {
        FileInputStream fileInputStream = null;
        Scanner scanner = null;
        try {
            fileInputStream = new FileInputStream(path);
            scanner = new Scanner(fileInputStream, "UTF-8");
            while (scanner.hasNext()) {
                String line = scanner.nextLine();
                System.out.println(line);
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            if (fileInputStream != null) {
                try {
                    fileInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (scanner != null) {
                scanner.close();
            }
        }

    }
	
	public static void write() throws IOException{
		  File file = new File("i:/test/"+File.separator+"hello.txt") ;
		  if(!file.exists()){
			  
			  file.createNewFile() ;
		  }
		  OutputStream out = new FileOutputStream(file) ;
		  byte[] bt = new byte[1024] ;
		  bt = "aa|bb|cc|dd|ee|ff|gg|hh|jj".getBytes() ;
		  for (int j = 0; j < bt.length; j++) {
			  out.write(bt) ;
		}
		  out.close();
		  
	  }
	
	public static void readCache(String path) {
        String filename = path;
        File file = new File(filename);

        BufferedReader reader = null;
        try {
            reader = new BufferedReader(new FileReader(file), 10 * 1024 * 1024);   //读大文件 设置缓存
            String tempString = null;
            while ((tempString = reader.readLine()) != null) {
                System.out.println(tempString);
            }
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

        }
    }
	
	 
	 
	 public static void write2() throws IOException{
			//判断目录是否存在
				File file = new File("i:/test/"+File.separator+"hello.txt");
				if(!file.exists()){
					file.createNewFile() ;
				}
				FileWriter fw = new FileWriter("i:/test/"+File.separator+"hello.txt", false) ;
				
				BufferedWriter bw = new BufferedWriter(fw) ;
				for (int i = 0; i < 1000000; i++) {
					bw.write("aa|bb|cc|dd|ee|ff|gg|hh|jj") ;//文件开始标识 长度20，左对齐，右补空格
					bw.newLine();
				}
				bw.flush() ; //将数据更新至文件
				bw.close() ;
				fw.close() ;
			  
		  }
	  
	 
	
	public static void main(String[] args) {
		String path = "i:/test/"+File.separator+"hello.txt" ;
		long b1 = System.currentTimeMillis() ;
		testReadFile(path) ;
		long e1 = System.currentTimeMillis() ;
		long b2 = System.currentTimeMillis() ;
		testScannerReadFile(path) ;
		long e2 = System.currentTimeMillis() ;
		long b3 = System.currentTimeMillis() ;
		readCache(path) ;
		long e3 = System.currentTimeMillis() ;
		System.out.println("|"+(b1-e1)+"|"+(b2-e2)+"|"+(b3-e3)+"|");
	}
}

 

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