Java 文件操作

package com.file.test;



import java.io.BufferedInputStream;

import java.io.BufferedReader;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.util.logging.Level;

import java.util.logging.Logger;



/**

 * @date 2015-3-17 7:52:06

 * @author y

 * @desc 

 */

public class FileTest {

    

    /**

     * 通过　BufferedReader 读取文本文件

     * 使用此种方式进进行读取文件,将会忽略回车换行等字符

     * 读取中文推荐此种方式

     * @param fileName 

     */

    public static void readFileByBufferedReader(String fileName){

        FileReader fr = null;

        BufferedReader br = null;

        StringBuilder sb = new StringBuilder();

        

        try {

            fr = new FileReader(fileName);

            br = new BufferedReader(fr);

            

            String line;

            while((line=br.readLine())!=null){

                sb.append(line);

            }

            

            System.out.println("str:"+sb.toString());

            System.out.println("str.length:"+sb.length());

        } catch (FileNotFoundException ex) {

            Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

        } catch (IOException ex) {

            Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

        }finally{

            try {

                if(null!=br){

                    br.close();

                }

                if(null!=fr){

                    fr.close();

                }

            } catch (IOException ex) {

                Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

            }

        }

    }



    /**

     * 通过 BufferedInputStream 读取文件

     * 此种方式存在中文乱码问题，关键点在这里：

     * byte buffer[]=new byte[1024];  有可能中文被读取了半个字节

     * 使用ByteArrayOutputStream解决中文乱码问题

     * @param fileName 

     */

    public static void readFileByBufferedInputStream(String fileName){

        File file = new File(fileName);

        

        FileInputStream fis = null;

        BufferedInputStream bis = null;

        ByteArrayOutputStream baos = null;

        

        StringBuilder sb = new StringBuilder();

        

        try {

            fis = new FileInputStream(file);

            bis = new BufferedInputStream(fis);

            baos = new ByteArrayOutputStream();

            

            

            byte buffer[]=new byte[2];

            int b;

            while((b=bis.read(buffer))>0){

                baos.write(buffer, 0, b);

            }

            

            sb.append(baos.toString());

            

            System.out.println("str:"+sb.toString());

            System.out.println("str.length:"+sb.length());

        } catch (FileNotFoundException ex) {

            Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

        } catch (IOException ex) {

            Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

        }finally{

            try {

                if(null!=baos){

                    baos.close();

                }

                if(null!=bis){

                    bis.close();

                }

                if(null!=fis){

                    fis.close();

                }

            } catch (IOException ex) {

                Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

            }

        }

    }

    

    /**

     * 创建文件

     * @param fileName 

     */

    public static void createFile(String fileName){

        try {

            File file = new File(fileName);

            

            if(!file.exists()){

                file.createNewFile();

                

                System.out.println("文件创建成功");

            }else{

                System.out.println("文件已经存在");

            }

        } catch (IOException ex) {

            Logger.getLogger(FileTest.class.getName()).log(Level.SEVERE, null, ex);

        }

    }

}