1、利用 File、FileInputStream、BufferedInputStream、DataInputStream、FileOutputStream、 BufferedOutputStream、DataOutputStream 写一个文件复制
程序。 代码: import java.io.*; class copyfile{ public static void main ( String[] args ) { DataInputStream instr; DataOutputStream outstr; if ( args.length != 2 ) { System.out.println("Please Enter file names!"); return; } File inFile = new File( args[0] ); File outFile = new File( args[1] ); if ( outFile.exists() ) { System.out.println( args[1] + " already exists"); return; } if ( !inFile.exists() ) { System.out.println( args[0] + " does not exist"); return; } try{ instr = new DataInputStream(new BufferedInputStream( new FileInputStream( inFile ))); outstr = new DataOutputStream(new BufferedOutputStream( new FileOutputStream( outFile ))); try { int data; while ( true ) { data = instr.readUnsignedByte() ; outstr.writeByte( data ) ; } } catch ( EOFException eof ) { outstr.close(); instr.close(); return; } } catch ( FileNotFoundException nfx ) { System.out.println("Problem opening files" ); } catch ( IOException iox ) { System.out.println("IO Problems" ); } } } 2、创建一个书籍对象,并把它输出到一个文件 book.dat 中,然后再把该对象读出来,在屏 幕上显示对象信息。 代码: import java.io.*;
class Book implements Serializable { int id; String name; String author; float price; public Book(int id,String name,String author,float price) { this.id=id; this.name=name; this.author=author; this.price=price; } } public class serializable{ public static void main(String args[]) throws IOException,ClassNotFoundException { Book book=new Book(100032,"
Java ProgrammingSkills","Wang Sir",30); ObjectOutputStream oos=new ObjectOutputStream( new FileOutputStream("c:/book.dat")); oos.writeObject(book); oos.close(); book=null; ObjectInputStream ois=new ObjectInputStream( new FileInputStream("c:/book.dat")); book=(Book)ois.readObject(); ois.close(); System.out.println("ID is:"+book.id); System.out.println("name is:"+book.name); System.out.println("author is:"+book.author); System.out.println("price is:"+book.price); } }