字节流跟字符流读取文件

字节流和字符流读取文件

package io;

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 javax.servlet.http.HttpServletRequest;

public class ReadFile {
	public static void main(String[] args) {
		/** 读取字符流文件，并且把此文件复制到本地磁盘 */
		String fromPath = "f://每日任务.txt";
		String toPath = "f://1.txt";
		ReadFile.readAndWriteTxt(fromPath, toPath);

		/** 读取字节流文件，并且把此文件复制到本地磁盘 */
		// String fromPath = "f://3.gif";
		// String toPath = "f://1.gif";
		// ReadFile.readAndWriteImg(fromPath, toPath);
	}

	/**
	 * FileInputStream 用于读取诸如图像数据之类的原始字节流。要读取字符流，请考虑使用 FileReader。
	 * 
	 * @param fromPath
	 * @param toPath
	 */
	public static void readAndWriteImg(String fromPath, String toPath) {

		File file = new File(fromPath);
		try {
			FileInputStream is = new FileInputStream(file);
			FileOutputStream os = new FileOutputStream(toPath);
			byte[] b = new byte[1024];
			while (is.read(b) != -1) {
				os.write(b);
			}
			os.close();
			is.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * FileReader 用于读取字符流。要读取原始字节流，请考虑使用 FileInputStream。
	 * 
	 * @param fromPath
	 * @param toPath
	 */
	public static void readAndWriteTxt(String fromPath, String toPath) {

		File file = new File(fromPath);
		try {
			FileReader ir = new FileReader(file);
	        BufferedReader br = new BufferedReader(ir);  
			FileWriter ow = new FileWriter(toPath);
			BufferedWriter bw=new BufferedWriter(ow);
			char[] b = new char[1024];
			while (ir.read(b) != -1) {
				ow.write(b);
			} 
			ow.close();
			ir.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	/**
	 * 把文本内容输出到控制台和页面，这个是在jsp页面上调用的方法
	 
	 */
	public static String getTxt(HttpServletRequest request) {

		String fromPath = "f://每日任务.txt";
		StringBuffer sb=new StringBuffer();
		File file = new File(fromPath);
		try {
			FileReader ir = new FileReader(file);
	        BufferedReader br = new BufferedReader(ir);  
			String output;
			while((output=br.readLine())!=null){ 
				sb.append(output+"\n");
				System.out.println(output); 
			} 
			ir.close();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return sb.toString();
	}

}

jsp页面调用getTxt（）

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@page import="io.ReadFile"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
<%  
	String content = ReadFile.getTxt(request); 
%>
</head>
<body>
<%=content %>
</body>
</html>

字节流跟字符流读取文件

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