Java Reader close()用法及代碼示例

Java中Reader類的close()方法用於關閉流並釋放流中繁忙的資源(如果有)。此方法具有以下結果：

如果流是打開的，則關閉流以釋放資源
如果流已經關閉，則將無效。
如果對流執行任何讀取或其他類似操作，則在關閉後，將引發IOException

用法:

public abstract void close()

參數：此方法不接受任何參數

返回值：此方法不返回任何值。

異常：如果輸入輸出時發生某些錯誤，則此方法將引發IOException。

下麵的方法說明了close()方法的用法方式：

示例1:

// Java program to demonstrate 
// Reader close() method 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        try { 
  
            String str = "GeeksForGeeks"; 
  
            // Create a Reader instance 
            Reader reader 
                = new StringReader(str); 
  
            // Get the character 
            // to be read from the stream 
            int ch; 
  
            // Read the first 5 characters 
            // to this reader using read() method 
            // This will put the str in the stream 
            // till it is read by the reader 
            for (int i = 0; i < 5; i++) { 
                ch = reader.read(); 
                System.out.println("\nInteger value "
                                   + "of character read: "
                                   + ch); 
                System.out.println("Actual "
                                   + "character read: "
                                   + (char)ch); 
            } 
  
            // Close the stream using close() 
            reader.close(); 
            System.out.println("Stream Closed."); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

Integer value of character read: 71
Actual character read: G

Integer value of character read: 101
Actual character read: e

Integer value of character read: 101
Actual character read: e

Integer value of character read: 107
Actual character read: k

Integer value of character read: 115
Actual character read: s
Stream Closed.

示例2:

// Java program to demonstrate 
// Reader close() method 
  
import java.io.*; 
import java.util.*; 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        try { 
            String str = "GeeksForGeeks"; 
  
            // Create a Reader instance 
            Reader reader 
                = new StringReader(str); 
  
            // Close the stream using close() 
            reader.close(); 
            System.out.println("Stream Closed."); 
  
            // Check if the Reader is 
            // ready to be read using ready() 
            System.out.println("Is Reader ready "
                               + "to be read"
                               + reader.ready()); 
        } 
        catch (Exception e) { 
            System.out.println(e); 
        } 
    } 
}

輸出：

Stream Closed.
java.io.IOException: Stream closed

參考： https://docs.oracle.com/javase/9/docs/api/java/io/Reader.html#close–

相關用法

注：本文由純淨天空篩選整理自Code_r大神的英文原創作品 Reader close() method in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。