Java SimpleScriptContext removeAttribute()用法及代碼示例

SimpleScriptContext類的removeAttribute()方法用於刪除給定範圍中的屬性，並且屬性和範圍的名稱作為參數傳遞。

用法:

public Object removeAttribute(String name, int scope)

參數：此方法接受兩個參數：

name這是屬性的名稱，
scope這是刪除屬性的範圍。

返回值：此方法返回刪除的值。

異常：此方法引發以下異常：

NullPointerException ：如果名稱為null。
IllegalArgumentException：如果名稱為空或範圍無效。

以下示例程序旨在說明SimpleScriptContext.removeAttribute()方法：
程序1:

// Java program to demonstrate 
// SimpleScriptContext.removeAttribute() method 
  
import javax.script.ScriptContext; 
import javax.script.SimpleScriptContext; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create SimpleScriptContext object 
        SimpleScriptContext simple 
            = new SimpleScriptContext(); 
  
        // add some attribute 
        simple.setAttribute( 
            "name", "Value", 
            ScriptContext.ENGINE_SCOPE); 
  
        // remove using removeAttribute() 
        Object removedObject 
            = simple.removeAttribute( 
                "name", 
                ScriptContext.ENGINE_SCOPE); 
  
        // print 
        System.out.println("Removed Object:"
                           + removedObject); 
    } 
}

輸出：

Removed Object:Value

程序2:

// Java program to demonstrate 
// SimpleScriptContext.removeAttribute() method 
  
import javax.script.ScriptContext; 
import javax.script.SimpleScriptContext; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // create SimpleScriptContext object 
        SimpleScriptContext simple 
            = new SimpleScriptContext(); 
  
        // add some attribute 
        simple.setAttribute("Team1", "India", 
                            ScriptContext.ENGINE_SCOPE); 
        simple.setAttribute("Team2", "Japan", 
                            ScriptContext.ENGINE_SCOPE); 
        simple.setAttribute("Team3", "Nepal", 
                            ScriptContext.GLOBAL_SCOPE); 
  
        // remove using removeAttribute() 
        Object remove1 
            = simple.removeAttribute( 
                "Team1", 
                ScriptContext.ENGINE_SCOPE); 
        Object remove2 
            = simple.removeAttribute( 
                "Team2", 
                ScriptContext.ENGINE_SCOPE); 
  
        // print scopes of different teams 
        System.out.println("Removed:" + remove1); 
        System.out.println("Removed:" + remove2); 
    } 
}

輸出：

Removed:India
Removed:Japan

參考：https：//docs.oracle.com/javase/10/docs/api/javax/script/SimpleScriptContext.html#removeAttribute(java.lang.String，int)

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注：本文由純淨天空篩選整理自AmanSingh2210大神的英文原創作品 SimpleScriptContext removeAttribute() 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。