IO流(复制文本文件的5种方式案例（用字符流）

妖狐艹你老母 2022-08-02 15:50 221阅读 0赞

package cn.itcast_01;
    
    import java.io.BufferedReader;
    import java.io.BufferedWriter;
    import java.io.FileReader;
    import java.io.FileWriter;
    import java.io.IOException;
    
    /*
     * 复制文本文件
     * 
     * 分析：
     * 		复制数据，如果我们知道用记事本打开并能够读懂，就用字符流，否则用字节流。
     * 		通过该原理，我们知道我们应该采用字符流更方便一些。
     * 		而字符流有5种方式，所以做这个题目我们有5种方式。推荐掌握第5种。
     * 数据源：
     * 		c:\\a.txt -- FileReader -- BufferdReader
     * 目的地：
     * 		d:\\b.txt -- FileWriter -- BufferedWriter
     */
    public class CopyFileDemo {
    	public static void main(String[] args) throws IOException {
    		String srcString = "c:\\a.txt";
    		String destString = "d:\\b.txt";
    		// method1(srcString, destString);
    		// method2(srcString, destString);
    		// method3(srcString, destString);
    		// method4(srcString, destString);
    		method5(srcString, destString);
    	}
    
    	// 字符缓冲流一次读写一个字符串
    	private static void method5(String srcString, String destString)
    			throws IOException {
    		BufferedReader br = new BufferedReader(new FileReader(srcString));
    		BufferedWriter bw = new BufferedWriter(new FileWriter(destString));
    
    		String line = null;
    		while ((line = br.readLine()) != null) {
    			bw.write(line);
    			bw.newLine();
    			bw.flush();
    		}
    
    		bw.close();
    		br.close();
    	}
    
    	// 字符缓冲流一次读写一个字符数组
    	private static void method4(String srcString, String destString)
    			throws IOException {
    		BufferedReader br = new BufferedReader(new FileReader(srcString));
    		BufferedWriter bw = new BufferedWriter(new FileWriter(destString));
    
    		char[] chs = new char[1024];
    		int len = 0;
    		while ((len = br.read(chs)) != -1) {
    			bw.write(chs, 0, len);
    		}
    
    		bw.close();
    		br.close();
    	}
    
    	// 字符缓冲流一次读写一个字符
    	private static void method3(String srcString, String destString)
    			throws IOException {
    		BufferedReader br = new BufferedReader(new FileReader(srcString));
    		BufferedWriter bw = new BufferedWriter(new FileWriter(destString));
    
    		int ch = 0;
    		while ((ch = br.read()) != -1) {
    			bw.write(ch);
    		}
    
    		bw.close();
    		br.close();
    	}
    
    	// 基本字符流一次读写一个字符数组
    	private static void method2(String srcString, String destString)
    			throws IOException {
    		FileReader fr = new FileReader(srcString);
    		FileWriter fw = new FileWriter(destString);
    
    		char[] chs = new char[1024];
    		int len = 0;
    		while ((len = fr.read(chs)) != -1) {
    			fw.write(chs, 0, len);
    		}
    
    		fw.close();
    		fr.close();
    	}
    
    	// 基本字符流一次读写一个字符
    	private static void method1(String srcString, String destString)
    			throws IOException {
    		FileReader fr = new FileReader(srcString);
    		FileWriter fw = new FileWriter(destString);
    
    		int ch = 0;
    		while ((ch = fr.read()) != -1) {
    			fw.write(ch);
    		}
    
    		fw.close();
    		fr.close();
    	}
    }