Java IO流

第一种通过字节对文件读取

package class04.filems;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Scanner;

/**
编写一个文件操作类（FileOperation），具有复制和剪切两个方法，要求：
    源路径和目标路径由控制台输入
    使用静态方法
 * */

public class FileOperation {

    public static String copyFile(String path) throws IOException {
        StringBuffer sb = new StringBuffer();
        File file = new File(path);
        
        if(!file.isFile() || !file.exists()) {
            return "";
        }
        
        FileInputStream inputStream = new FileInputStream(file);
        for(int i = 0; i < file.length(); i++ ) {
            //read()方法可填写byte数组
            sb.append((char)inputStream.read());
        }
        inputStream.close();
        return sb.toString();
    }
    
    public static boolean pasteFile(String path, String txt) throws IOException {
        File file = new File(path);
        
        FileOutputStream outputStream = new FileOutputStream(file);
        for(int i = 0; i < txt.length(); i++ ) {
            //write()方法可填写byte数组
            outputStream.write(txt.charAt(i));
        }
        outputStream.close();
        return true;
    }
    
    
    public static void main(String[] args) throws IOException {
        String txt = "2018 FIFA World Cup will play in Russia.";
        pasteFile("D:\data.txt", txt);
        System.out.println(copyFile("D:\data.txt"));
    }

}

第二种

package class04.filems;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class FileOperationT {

    public static String readFile(String path) throws IOException {
        File file = new File(path);
        FileReader fr = new FileReader(file);
        BufferedReader bf = new BufferedReader(fr);
        
        StringBuffer sb = new StringBuffer();
        String string = "";
        
        while((string = bf.readLine()) != null) {
            sb.append(string);
        }
        bf.close();
        fr.close();
        return sb.toString();
    }
    
    public static boolean writeFile(String path, String txt) throws IOException {
        File file = new File(path);
        FileWriter fw = new FileWriter(file);
        BufferedWriter bw = new BufferedWriter(fw);
        for(int i = 0; i < txt.length(); i++ ) {
            bw.write(txt.charAt(i));
        }
        bw.newLine();
        bw.close();
        fw.close();
        return true;
    }
    
    public static void main(String[] args) throws IOException {
        String txt = FileOperationT.readFile("D:\data.txt");
        System.out.println(txt);
        FileOperationT.writeFile("D:\data2.txt", txt);
    }

}