第十章编程作业

1 ) 实现字节数组和任何基本类型和引用类型执行的相互转换

​​提示：使用ByteArrayInutStream和ByteArrayOutputStream。​​

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.Arrays;
import java.util.Date;

public class Work01 {
  
  public static void main(String[] args) throws IOException, ClassNotFoundException {
    
    // 字节数组输入流
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    // 对象输出流
    ObjectOutputStream oos = new ObjectOutputStream(bos);
    
    // 操作(写)
    oos.writeBoolean(false);
    oos.writeUTF("你好,世界！");
    oos.writeInt(123);
    oos.writeObject("Hello,world");
    // 时间对象的序列化
    oos.writeObject(new Date());
    // 自定义类对象的序列化
    oos.writeObject(new Students("小万", 98, 18));
    
    
    byte[] datas = bos.toByteArray();
    System.out.println(Arrays.toString(datas));   
    
    // 创建字节数组输入流
    ByteArrayInputStream bis = new ByteArrayInputStream(datas);
    // 创建对象输入流
    ObjectInputStream ois = new ObjectInputStream(bis);
    
    // 操作(读取数据,按照顺序)
    boolean flag = ois.readBoolean();
    System.out.println(flag);
    
    String str1 = ois.readUTF();
    System.out.println(str1);
    
    int a = ois.readInt();
    System.out.println(a);
    
    Object ss = ois.readObject();
    if(ss instanceof String) {
      String str = (String)ss;
      System.out.println(str);  
    }
    
    Object obj = ois.readObject();
    if(obj instanceof Date) {
      Date date = (Date)obj;
      System.out.println(date);
    }
    
    obj = ois.readObject();
    if(obj instanceof Students) {
      
      Students stu = (Students)obj;
      System.out.println(""+stu.getName()+"--"+stu.getScore()+"--"+stu.getAge());
      
      System.out.println();
    }
  }
}

class Students implements java.io.Serializable{
  
  private String name;
  private int score;
  private transient int age;
  
  public String getName() {
    return name;
  }
  public void setName(String name) {
    this.name = name;
  }
  public int getScore() {
    return score;
  }
  public void setScore(int score) {
    this.score = score;
  }
  public int getAge() {
    return age;
  }
  public void setAge(int age) {
    this.age = age;
  }
  
  public Students(String name, int score, int age) {
    super();
    this.name = name;
    this.score = score;
    this.age = age;
  }
}

2 ) 复制文件夹d:/sxtjava下面所有文件和子文件夹内容到d:/sxtjava2。

​​提示：涉及单个文件复制、目录的创建、递归的使用​​

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class Work02 {
  
  private static File srcFile = new File("/home/sweetheart/eclipse-workspace");
  private static File destFile = new File("/home/sweetheart/eclipse-workspace-copy");
  private static boolean flag = true;
  private static String fileName = "/home/sweetheart/eclipse-workspace";
  private static String fileName1 = "/home/sweetheart/eclipse-workspace-copy";
  
  public static void main(String[] args) {
    
    copy(srcFile);
  }
  
  public static void copy(File f) {
    
    if(flag) {  // 如果是顶层文件夹
      flag = false;
      destFile.mkdir();
      File[] files = f.listFiles();
      
      for(File file:files) {
        copy(file);
      }
      
    }else {
      
      String destpath = f.getAbsolutePath().replace(fileName, fileName1);
      System.out.println(destpath);
      
      File f1 = new File(destpath);
      
      
      if(f.isFile()) {
        // 是文件的话直接拷贝
        copyDetial(f,f1);
        
      }else {
        // 文件夹的话先创建
        f1.mkdir();
        // 列出子级文件对象
        File[] files = f.listFiles();
        
        // 递归调用
        for(File file:files) {
          copy(file);
        }
      } 
    }
  }
  
  // 拷贝具体的文件(从源路径到目标路径)
  public static void copyDetial(File src,File dest){
    
    // 选择流
    try(InputStream is = new FileInputStream(src);
      OutputStream os = new FileOutputStream(dest,true)){
      
      // 操作(拷贝)
      
      int len = -1;
      byte[] datas = new byte[1024];
      
      while((len=is.read(datas))!=-1) {
        os.write(datas,0,len);
      }
      
      os.flush();
    } catch (FileNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } 
  }
}

3 ) 使用IO包中的类读取D盘上exam.txt文本文件的内容，每次读取一行内容，将每行作为一个输入放入ArrayList的泛型集合中并将集合中的内容使用加强for进行输出显示。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;

import java.util.ArrayList;
import java.util.List;



public class Work03 {

  public static void main(String[] args) {
    
    // 创建集合用来存储读取到的数据
    List<String> textList = new ArrayList<>();
    
    // 创建源
    File src = new File("exam.txt");
    
    // 选择流(采用try-catch-with...关闭)
    try(BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(src)))){
      
      String strLine = null;
      // 循环读取并添加到集合中
      while((strLine=br.readLine())!=null) {
        
        textList.add(strLine);
        
      }
      
      // 利用增强for打印
      for(String str:textList) {
        
        System.out.println(str);
      }
      
    } catch (FileNotFoundException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    } catch (IOException e1) {
      // TODO Auto-generated catch block
      e1.printStackTrace();
    } 
    
  }
}