java 集合addall

集合类的addAll()方法 (Collections Class addAll() method)

• addAll() Method is available in java.lang package.

  addAll()方法在java.lang包中可用。

• addAll() Method is used to put all the given elements(ele) to the given collection (co).

  addAll()方法用于将所有给定的element( ele )放入给定的集合( co )。

• addAll() Method is a static method, it is accessible with the class name and if we try to access the method with the class object then we will not get an error.

  addAll()方法是一个静态方法，可以使用类名进行访问，如果尝试使用类对象访问该方法，则不会收到错误。

• addAll() Method may throw an exception at the time of add the elements(ele) to the given Collection(co).

  在将elements( ele )添加到给定Collection( co )时， addAll()方法可能会引发异常。

  • UnsupportedOperationException: This exception may throw when collection unsupport add() method.UnsupportedOperationException ：集合不支持add()方法时，可能引发此异常。
  • NullPointerException: This exception may throw when elements (ele) may have at least one null & the given collection unsupport null.
  • NullPointerException ：当元素( ele )可能至少具有一个null且给定的集合不支持null时，可能引发此异常。
  • IllegalArgumentException: This exception may throw when the given element (ele) is not valid.
  • IllegalArgumentException ：如果给定元素( ele )无效，则可能引发此异常。

Syntax:

句法：

    public static boolean addAll(Collection co, Type.. ele);

Parameter(s):

参数：

• Collection co – represents the container of "Collection" type.

  集合co –表示“集合”类型的容器。

• Type.. ele – represents the elements to add into given collection co.

  Type .. ele –表示要添加到给定集合co中的元素。

Return value:

返回值：

The return type of the method is Boolean, it returns true when the given set of elements(ele) to be added into collection successfully otherwise it returns false.

该方法的返回类型为Boolean ，如果要成功将给定的元素集(ele)添加到集合中，则返回true，否则返回false。

Example:

例：

// Java Program is to demonstrate the example
// of boolean addAll(Collection co, Type.. ele) of Collections class
import java.util.*;
public class AddAll {public static void main(String args[]) {// Create a linked list object
List link_list = new LinkedList();
// By using add() method is to add the
// given elements in linked list
link_list.add(10);
link_list.add(20);
link_list.add(30);
link_list.add(40);
link_list.add(50);
//Display Linked List
System.out.println("link_list: " + link_list);
// By using addAll() method is to add all the
// elements in the given collection linked list
boolean status = Collections.addAll(link_list, 60, 70, 80, 90);
System.out.println();
System.out.println("Collections.addAll(link_list, 60,70,80,90) :");
// Display Linked List
System.out.println("link_list: " + link_list);
}
}

Output

输出量

link_list: [10, 20, 30, 40, 50]Collections.addAll(link_list, 60,70,80,90) :
link_list: [10, 20, 30, 40, 50, 60, 70, 80, 90]

翻译自: https://www.includehelp.com/java/collections-addall-method-with-example.aspx

java 集合addall