Queue 中 add() 和 offer() 区别

• 在做Leetcode算法题的时候，看到大神们往队列中添加元素都是用offer。看看add和offer的区别

• 截一下Jdk1.8的Queue接口中对add和offer方法的描述：（高亮部分是重点）

    
     @return {@code true} (as specified by {@link Collection#add})
     @throws IllegalStateException if the element cannot be added at this
     *         time due to capacity restrictions
     
    boolean add(E e);


     * Inserts the specified element into this queue if it is possible to do
     * so immediately without violating capacity restrictions.
     * When using a capacity-restricted queue, this method is generally
     * preferable to {@link #add}, which can fail to insert an element only
     * by throwing an exception.
     *
      
     @return {@code true} if the element was added to this queue, else
             {@code false}
    
    boolean offer(E e);

• 我们可以看到add方法在添加成功的时候，返回true；但是失败的时候回抛出异常IllegalStateException；
• offer方法添加成功时返回true，失败返回false；