Java属性setProperty（）方法与示例：java中的property

java中的property

属性类setProperty()方法 (Properties Class setProperty() method )

setProperty() method is available in java.utilpackage.

setProperty()方法在java.util包中可用。

setProperty() method is used to set the given value element (val_ele) associated with the given key element (key_ele) when no value element associate previously otherwise it replaces the old value with the given value for the given key of this Properties.

setProperty()方法用于设置与给定键元素(key_ele)关联的给定值元素(val_ele)，前提是之前没有关联的值元素，否则它将用此属性的给定键的给定值替换旧值。

setProperty() 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.

setProperty()方法是一个非静态方法，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。

setProperty() method does not throw an exception at the time of setting the property.

setProperty()方法在设置属性时不会引发异常。

Syntax:

句法：

    public Object setProperty(String key_ele, String val_ele);

Parameter(s):

参数：

String key_ele– represents the key element at which the value is to be set.

字符串key_ele –表示要在其上设置值的键元素。

String val_ele– represents the value element for the given key.

字符串val_ele –表示给定键的value元素。

Return value:

返回值：

The return type of the method is Object, it returns the old value linked with the given key if exists otherwise it returns null.

方法的返回类型为Object ，如果存在则返回与给定键链接的旧值，否则返回null。

Example:

例：

// Java program to demonstrate the example 
// of Object setProperty(String key_ele, String val_ele)
// method of Properties
 
import java.io.*;
import java.util.*;
 
public class SetPropertyOfProperties {
  
 public static void main(String arg[]) throws Exception {
  
  // Instantiate Properties object
  Properties prop = new Properties();
 
  prop.put("10", "C");
  prop.put("20", "C++");
  prop.put("30", "JAVA");
  prop.put("40", "PHP");
  prop.put("50", "SFDC");
 
  // By using setProperty() method is to
  // replace the old value for the given
  // key if exists with the given new value
  Object ob = prop.setProperty("20", "OOPS");
 
  // Display old value returned for the
  // given key element
  System.out.println("prop.setProperty(20,OOPS): " + ob);
 
  // Display updated list
  prop.list(System.out);
 }
}

Output

输出量

prop.setProperty(20,OOPS): C++
-- listing properties --
50=SFDC
40=PHP
30=JAVA
20=OOPS
10=C