Java HashSet contains（）方法与示例

- 日理万妓 2023-03-05 15:53 4阅读 0赞

## HashSet类contains()方法 **(**HashSet Class contains() method**)** ##

*  **contains() method** is available in java.util package.
    
    **contains()方法**在java.util包中可用。
 *  **contains() method** is used to check the existence of the given object (ob) in this HashSet.
    
    **contains()方法**用于检查此HashSet中给定对象(ob)的存在。
 *  **contains() 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.
    
    **contains()方法**是一个非静态方法，只能由类对象访问，如果尝试使用类名访问该方法，则会收到错误消息。
 *  **contains() method** does not throw an exception at the time of testing the existence of the given object.
    
    在测试给定对象的存在时， **contains()方法**不会引发异常。

**Syntax:**

**句法：**

public boolean contains (Object ob);

**Parameter(s):**

**参数：**

*  Object ob – represents the object whose existence is to be checked.
    
    对象ob –表示要检查其存在的对象。

**Return value:**

**返回值：**

The return type of the method is boolean, it returns true when the given object exists otherwise it returns false.

方法的返回类型为boolean ，当给定对象存在时返回true，否则返回false。

**Example:**

**例：**

// Java program to demonstrate the example 
    // of boolean contains (Object ob) method of HashSet 
    
    import java.util.*;
    
    public class ContainsOfHashSet {
        
        public static void main(String[] args) {
        
            // Instantiates a HashSet object
            HashSet < String > hs = new HashSet < String > ();
    
            // By using add() method is to add
            // the given object of this
            // HashSet 
            hs.add("C");
            hs.add("C++");
            hs.add("JAVA");
            hs.add("PHP");
            hs.add("SFDC");
    
            // Display HashSet
            System.out.println("HashSet: " + hs);
    
            // By using contains() method is to 
            // check whether the given object exists
            // or not exists in this HashSet
            boolean status = hs.contains("JAVA");
    
            // Display Status
            System.out.println("hs.contains(JAVA): " + status);
        }
    }

**Output**

**输出量**

HashSet: [JAVA, C++, C, SFDC, PHP]
    hs.contains(JAVA): true

> 翻译自: [https://www.includehelp.com/java/hashset-contains-method-with-example.aspx][https_www.includehelp.com_java_hashset-contains-method-with-example.aspx]

[https_www.includehelp.com_java_hashset-contains-method-with-example.aspx]: https://www.includehelp.com/java/hashset-contains-method-with-example.aspx