Java 中的 SimpleScriptContext getAttribute()方法,示例

原文:https://www . geesforgeks . org/simplescriptcontext-getattribute-method-in-Java-with-examples/

SimpleScriptContext 类的 getAttribute() 方法用于返回给定名称的属性值作为该方法的参数。通过属性名搜索值在搜索顺序中最早出现的范围内。

语法:

public Object getAttribute(String name)

参数:此方法接受单个参数名称,这是要检索的属性的名称。

返回值:该方法返回定义了给定名称的属性的最低范围内的属性的值,如果在任何范围内都不存在该名称的属性,则返回 null。

异常:该方法抛出以下异常:

  • NullPointRexception:如果名称为空。
  • IllegalArgumentException :如果名称为空。

下面的程序说明了 simplescriptcontext . getattribute()方法: 程序 1:

// Java program to demonstrate
// SimpleScriptContext.getAttribute() 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);

        // get value using getAttribute()
        Object value
            = simple.getAttribute("name");

        // print
        System.out.println(value);
    }
}

Output:

Value

程序 2:

// Java program to demonstrate
// SimpleScriptContext.getAttribute() 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.ENGINE_SCOPE);

        // get value using getAttribute()
        Object value1
            = simple.getAttribute("Team1");
        Object value2
            = simple.getAttribute("Team2");
        Object value3
            = simple.getAttribute("Team3");

        // print
        System.out.println(value1);
        System.out.println(value2);
        System.out.println(value3);
    }
}

Output:

India
Japan
Nepal

参考文献:https://docs . Oracle . com/javase/10/docs/API/javax/script/simplescriptcontext . html # GetAttribute(Java . lang . string)