Android中讓多個線程順序執行

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目錄(?)[+]

線程調度是指按照特定機制爲多個線程分配CPU的使用權。 
有兩種調度模型：分時調度模型和搶佔式調度模型。　　 
分時調度模型：是指讓所有的線程輪流獲得cpu的使用權,並且平均分配每個線程佔用的CPU的時間片。 
搶佔式調度模型：是指優先讓可運行池中優先級高的線程佔用CPU，如果可運行池中的線程優先級相同，那麼就隨機選擇一個線程，使其佔用CPU。處於運行狀態的線程會一直運行，直至它不得不放棄CPU。一個線程會因爲以下原因而放棄CPU： 
1 、Java虛擬機讓當前線程暫時放棄CPU，轉到就緒狀態，使其它線程或者運行機會。 
2、 當前線程因爲某些原因而進入阻塞狀態 
3、 線程結束運行 
需要注意的是，線程的調度不是跨平臺的，它不僅僅取決於java虛擬機，還依賴於操作系統。在某些操作系統中，只要運行中的線程沒有遇到阻塞，就不會放棄CPU；在某些操作系統中，即使線程沒有遇到阻塞，也會運行一段時間後放棄CPU，給其它線程運行的機會，java的線程調度是不分時的，同時啓動多個線程後，不能保證各個線程輪流獲得均等的CPU時間片。如果希望明確地讓一個線程給另外一個線程運行的機會，可以採取以下辦法之一：調整各個線程的優先級、讓處於運行狀態的線程調用、Thread.sleep()方法、讓處於運行狀態的線程調用Thread.yield()方法、讓處於運行狀態的線程調用另一個線程的join()方法

所以，讓多個線程順序執行有三個確切的辦法： 
1、改變線程的優先級（不同的系統上可能並不會按照優先級來執行） 
2、調用join()方法，一個線程在run中調用join()方法時，會阻塞當前線程，而讓新加入的線程執行完再執行本線程 
3、第三個方法是我自己想出來的，就是使用PriorityQueue優先隊列，PriorityQueue有這樣一個特徵，就是可以讓隊列中某個優先級最高元素最先出來，所以利用這個特性，可以讓我們想要哪個線程先執行就先執行，最後通過線程的State來判斷該線程是否執行完畢，再執行下一個線程，這個方法的一個好處是各線程之間不必使用join來執行了，各個線程可以獨立出來。

PriorityQueue的用法：

<code class="hljs lasso has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">PriorityQueue<span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;"><</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">Integer</span><span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">></span> <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span> <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">=</span> <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">new</span> PriorityQueue<span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;"><</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">Integer</span><span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">></span>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">11</span>, <span class="hljs-literal" style="color: rgb(0, 102, 102); box-sizing: border-box;">new</span> MyComparator());
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">-</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">6</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">9</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>add(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">2</span>);
        <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>offer(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8</span>);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span> (<span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">!</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>isEmpty()) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">Log</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>v(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"zxy"</span>, <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">queue</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">.</span>poll() <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">+</span> <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//9864321-2</span>
        }
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> static class MyComparator implements Serializable, Comparator<span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;"><</span><span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">Integer</span><span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">></span> {

        @Override
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> int compare(<span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">Integer</span> lhs, <span class="hljs-built_in" style="color: rgb(102, 0, 102); box-sizing: border-box;">Integer</span> rhs) {
            int value <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">=</span> lhs <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">></span> rhs <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">?</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> : lhs <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;"><</span> rhs <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">?</span> <span class="hljs-subst" style="color: rgb(0, 0, 0); box-sizing: border-box;">-</span><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> : <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> value;
        }
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; opacity: 0; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

上面這個示例就是優先隊列的基本用法，它可以傳入一個我們自定義的比較器，利用這個比較器我們可以自己定義隊列中元素的順序。其中compare（）方法中的返回值： 
1、>0：代表lhs>rhs 
2、<0：代表rhs>lhs 
3、==0：代表lhs==rhs

而PriorityQueue中有這麼幾個方法： 
1、queue.poll()：表示從隊列中取出隊首上的元素，且取出後remove掉這個元素 
2、queue.peek()：表示從隊列中取出隊首上的元素，且取出後不remove掉這個元素 
3、queue.add()：表示添加一個元素 
4、queue.clear()：表示清空隊列 
5、queue.remove()：表示移除某個元素 
6、queue.size()：表示隊列的size

利用優先隊列實現多個線程順序執行

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> PriorityQueue<Thread> queue = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> PriorityQueue<>(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">11</span>, <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> MyThreadComparator());
        queue.add(thread1);
        queue.add(thread2);
        queue.add(thread3);
        queue.add(thread5);
        queue.add(thread7);
        queue.add(thread6);
        queue.add(thread4);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> flag = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
        Thread mThread = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> i=<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> size = queue.size();
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span> (!queue.isEmpty()) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(!flag){
                mThread = queue.poll();
                mThread.start();
                flag = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
                i++;
            }
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(mThread.getState()== Thread.State.TERMINATED && !queue.isEmpty()){
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(size==i){
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">break</span>;
                }
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(size==(i+<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>)){
                    mThread = queue.peek();
                    mThread.start();
                    i++;
                }<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
                    mThread = queue.poll();
                    mThread.start();
                    i++;
                }
            }
        }
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MyThreadComparator</span> <span class="hljs-inheritance" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span></span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Serializable</span>, <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Comparator</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Thread</span>> {</span>

        @Override
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> compare(Thread lhs, Thread rhs) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> value = lhs.getPriority() < rhs.getPriority() ? <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> : lhs.getPriority() > rhs.getPriority() ? -<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> : <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> value;
        }
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; opacity: 0; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li></ul>

這裏每創建一個線程我都給它設置了一個自帶的優先級（其實這個只是一個標誌，你也可以用任何東西作爲標誌，比如採用），用來表示該線程的優先級：

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">Thread thread1 = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread( <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable() {
            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
                    Thread.sleep(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4000</span>);
                } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {
                    e.printStackTrace();
                }
                Log.v(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"zxy"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"result—>thread1"</span>);
            }
        });
        thread1.setPriority(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">3</span>);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; opacity: 0; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

利用它做的一些效果：