inputstream示例_Java InputStream mark（）方法与示例

朱雀 2023-03-05 15:53 174阅读 0赞

inputstream示例

## InputStream类mark()方法 **(**InputStream Class mark() method**)** ##

*  **mark() method** is available in java.io package.
    
    **mark()方法**在java.io包中可用。
 *  **mark() method** is used to mark the present position in this InputStream and when we call to reset() method it reset the stream to the position set by the most recent call of mark() method.
    
    **mark()方法**用于标记此InputStream中的当前位置，当我们调用reset()方法时，它将流重置到由mark()方法的最新调用设置的位置。
 *  **mark() method** is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
    
    **mark()方法**是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。
 *  **mark() method** does not throw an exception at the time of marking the stream.
    
    **mark()方法**在标记流时不会引发异常。

**Syntax:**

**句法：**

public void mark(int r_limit);

**Parameter(s):**

**参数：**

*  int r\_limit – represents the maximum number of bytes that can be read before the mark gets invalid.
    
    int r\_limit –表示标记无效之前可以读取的最大字节数。

**Return value:**

**返回值：**

The return type of the method is void, it returns nothing.

该方法的返回类型为void ，不返回任何内容。

**Example:**

**例：**

// Java program to demonstrate the example 
    // of void mark(int r_limit) method
    // of InputStream
    
    import java.io.*;
    
    public class MarkOfIS {
        
     public static void main(String[] args) throws Exception {
        
      InputStream is_stm = null;
      int val = 0;
    
      try {
        
       // Instantiates FileInputStream
       is_stm = new FileInputStream("D:\\includehelp.txt");
    
       // By using read() method isto 
       // read the character from is_stm
       char ch1 = (char) is_stm.read();
       char ch2 = (char) is_stm.read();
    
       System.out.println("ch1: " + ch1);
       System.out.println("ch2: " + ch2);
    
       // By using mark() method isto
       // set the current position in this
       // is_stm
    
       System.out.println("is_stm.mark(0): ");
       is_stm.mark(0);
       char ch3 = (char) is_stm.read();
       char ch4 = (char) is_stm.read();
    
       System.out.println("ch3: " + ch3);
       System.out.println("ch4: " + ch4);
    
       // By using reset() method isto
       // reset the stream to the position 
       // set by the call mark() method
    
       System.out.println("is_stm.reset(): ");
       is_stm.reset();
       char ch5 = (char) is_stm.read();
       char ch6 = (char) is_stm.read();
    
       System.out.println("ch3: " + ch5);
       System.out.println("ch4: " + ch6);
      } catch (Exception ex) {
        
       System.out.println("Reset Not Supported");
    
      } finally {
        
       // with the help of this block is to
       // free all necessary resources linked
       // with the stream
       if (is_stm != null) {
        
        is_stm.close();
       }
      }
     }
    }

**Output**

**输出量**

ch1: J
    ch2: A
    is_stm.mark(0):
    ch3: V
    ch4: A
    is_stm.reset():
    Reset Not Supported

> 翻译自: [https://www.includehelp.com/java/inputstream-mark-method-with-example.aspx][https_www.includehelp.com_java_inputstream-mark-method-with-example.aspx]

inputstream示例

[https_www.includehelp.com_java_inputstream-mark-method-with-example.aspx]: https://www.includehelp.com/java/inputstream-mark-method-with-example.aspx