【Java】18 增强流

public class BufferedDemo {
    public static void main(String[] args) throws FileNotFoundException {
      	// 记录开始时间
        long start = System.currentTimeMillis();
		// 创建缓冲流对象
        try (
			BufferedInputStream bis = new BufferedInputStream(new FileInputStream("jdk9.exe"));
		 	BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("copy.exe"));
        ){
          	// 读写数据
            int len;
            byte[] bytes = new byte[8 * 1024];
            while ((len = bis.read(bytes)) != -1) {
                bos.write(bytes, 0 , len);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
		// 记录结束时间
        long end = System.currentTimeMillis();
        System.out.println("缓冲流使用数组复制时间:" + (end - start) + " ms");
    }
}

public class BufferedReaderDemo {
    public static void main(String[] args) throws IOException {
      	 // 创建缓冲流对象
        BufferedReader br = new BufferedReader(new FileReader("in.txt"));
        BufferedWriter bw = new BufferedWriter(new FileWriter("out.txt"));
        
		// 定义字符串,保存读取的一行文字
        String line = null;
      	// 循环读取,读取到最后返回null
        while ((line = br.readLine()) != null) {
           	// 写出数据
	        bw.write(line);
	      	// 写出换行
	        bw.newLine();
        }
        
		// 释放资源
        br.close();
        bw.close();
    }
}

public class ReaderDemo2 {
    public static void main(String[] args) throws IOException {
      	// 定义文件路径,文件为gbk编码
        String FileName = "E:\\file_gbk.txt";
      	// 创建流对象,默认UTF8编码
        InputStreamReader isr = new InputStreamReader(new FileInputStream(FileName));
      	// 创建流对象,指定GBK编码
        InputStreamReader isr2 = new InputStreamReader(new FileInputStream(FileName) , "GBK");
		// 定义变量,保存字符
        int read;
      	// 使用默认编码字符流读取,乱码
        while ((read = isr.read()) != -1) {
            System.out.print((char)read); // ��Һ�
        }
        isr.close();
      
      	// 使用指定编码字符流读取,正常解析
        while ((read = isr2.read()) != -1) {
            System.out.print((char)read);// 大家好
        }
        isr2.close();
    }
}

public class OutputDemo {
    public static void main(String[] args) throws IOException {
      	// 定义文件路径
        String FileName = "E:\\out.txt";
      	// 创建流对象,默认UTF8编码
        OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream(FileName));
        // 写出数据
      	osw.write("你好"); // 保存为6个字节
        osw.close();
      	
		// 定义文件路径
		String FileName2 = "E:\\out2.txt";
     	// 创建流对象,指定GBK编码
        OutputStreamWriter osw2 = new OutputStreamWriter(new FileOutputStream(FileName2),"GBK");
        // 写出数据
      	osw2.write("你好");// 保存为4个字节
        osw2.close();
    }
}

// 将要被序列化的实体类
public class Student implements Serializable {
	// 加入序列版本号
    private static final long serialVersionUID = 1L;
    public String name;
    public transient int age; // transient 瞬态修饰成员,不会被序列化
    public void show() {
      	System.out.println(name + " -- " + age);
    }
}

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// 序列化
public class SerializeDemo{
   	public static void main(String [] args)   {
   		// 创建对象
    	Student stu = new Student();
    	stu.name = "zhangsan";
    	stu.age = 20; 
    	
    	try {
      		// 创建序列化流对象
          	ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("stu.txt"));
        	// 写出对象
        	out.writeObject(stu);
        } catch(IOException i)   {
            i.printStackTrace();
        } finally {
            // 释放资源
        	out.close();
        }
   	}
}

public class DeserializeDemo {
   public static void main(String [] args)   {
        Student stu = null;
        try {		
             // 创建反序列化流
             ObjectInputStream in = new ObjectInputStream(new FileInputStream("stu.txt"));
             // 读取一个对象
             stu = (Student) in.readObject();
        } catch(IOException i) {
             // 捕获其他异常
             i.printStackTrace();
             // 结束执行
             return;
        } catch(ClassNotFoundException c)  {
        	 // 捕获类找不到异常
             c.printStackTrace();
             // 结束执行
             return;
        } finally {
             // 释放资源
             in.close();
        }
        
        // 无异常,直接打印输出
        System.out.println("Name: " + stu.name);	// zhangsan
        System.out.println("age: " + stu.age); // 0
    }
}