convert.html

@@ -56,7 +56,21 @@
     <span class="kd">public</span> <span class="o">&lt;</span><span class="n">T</span><span class="o">&gt;</span> <span class="n">T</span> <span class="nf">convertFrom</span><span class="o">(</span><span class="kd">final</span> <span class="n">Type</span> <span class="n">type</span><span class="o">,</span> <span class="kd">final</span> <span class="kt">char</span><span class="o">[]</span> <span class="n">text</span><span class="o">,</span> <span class="kt">int</span> <span class="n">start</span><span class="o">,</span> <span class="kt">int</span> <span class="n">len</span><span class="o">);</span>
 
     <span class="kd">public</span> <span class="o">&lt;</span><span class="n">T</span><span class="o">&gt;</span> <span class="n">T</span> <span class="nf">convertFrom</span><span class="o">(</span><span class="kd">final</span> <span class="n">Type</span> <span class="n">type</span><span class="o">,</span> <span class="kd">final</span> <span class="n">ByteBuffer</span><span class="o">...</span> <span class="n">buffers</span><span class="o">);</span></pre></div>
-            <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;基本用法：</p>
+
+            <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Convert 与 ByteBuffer 的结合 </p>      
+            <p id="json_net_bytebuffer">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;从以上的方法可以看出，与其他JSON框架相比Convert多了与ByteBuffer结合的方法。特别是convertTo方法加了Supplier&lt;ByteBuffer&gt;方法，这么做是为了提高数据传输的性能。在大部分情况下JSON序列化得到的数据流是为了传输出去，常见的场景就是HTTP+JSON接口。Convert提供ByteBuffer接口会大量减少中间临时数据的产生。通常大家输出JSON数据的方法如下:
+            </p>
+            <div class="highlight"><pre>    <span class="kd">public</span> <span class="kt">void</span> <span class="nf">doPost</span><span class="o">(</span><span class="n">HttpServletRequest</span> <span class="n">req</span><span class="o">,</span> <span class="n">HttpServletResponse</span> <span class="n">resp</span><span class="o">)</span> <span class="kd">throws</span> <span class="n">ServletException</span><span class="o">,</span> <span class="n">IOException</span> <span class="o">{</span>
+        <span class="n">String</span> <span class="n">json</span> <span class="o">=</span> <span class="k">new</span> <span class="n">Gson()</span><span class="o">.</span><span class="na">toJson</span><span class="o">(record);</span>
+        <span class="n">resp</span><span class="o">.</span><span class="na">setContentType</span><span class="o">(</span><span class="s">&quot;text/json; charset=UTF-8&quot;</span><span class="o">);</span>
+        <span class="n">resp</span><span class="o">.</span><span class="na">getOutputStream</span><span class="o">().</span><span class="na">write</span><span class="o">(</span><span class="n">json</span><span class="o">.</span><span class="na">getBytes</span><span class="o">(</span><span class="s">&quot;UTF-8&quot;</span><span class="o">));</span>
+    <span class="o">}</span></pre></div>
+            <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;几乎所有的JSON框架提供的接口以String作为返回结果为主，其内在都是以char[]作为JsonWriter的载体。以Gson为例，Gson拼接JSON默认使用的是StringWriter，StringWriter的扩容策略是翻倍。为了方便计算，假设一个对象转换成JSON字符串大小为了10K。Gson在转换过程中产生的临时的char[]的大小: 16 + 32 + 64 + 128 + 256 + 512 + 1K + 2K + 4K + 8K + 16K = 32K, char[]转换成最终的String结果又会产生10K的char[], 最后在response输出时又回产生10K的byte[]（方便计算不考虑双字节）,也就是说整个对象输出过程中会产生52K的临时数据。同时常见的HTTP服务器(如实现java-servlet规范的服务器)不会把底层的ByteBuffer对象池暴露给上层。所以目前所有使用其他JSON框架输出数据都会产生5倍于数据体积大小的垃圾数据。而RedKale框架的HTTP服务内置了Convert的JSON接口，避免了这么大量的垃圾数据产生。</p>
+            <div class="highlight"><pre>    <span class="kd">protected</span> <span class="kt">void</span> <span class="nf">execute</span><span class="o">(</span><span class="n">HttpRequest</span> <span class="n">req</span><span class="o">,</span> <span class="n">HttpResponse</span> <span class="n">resp</span><span class="o">)</span> <span class="kd">throws</span> <span class="n">IOException</span> <span class="o">{</span>
+        <span class="n">resp</span><span class="o">.</span><span class="na">finishJson</span><span class="o">(</span><span class="n">record</span><span class="o">);</span>
+    <span class="o">}</span></pre></div>
+
+            <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;JSON基本用法：</p>
             <div class="highlight"><pre>    <span class="kd">public</span> <span class="kd">class</span> <span class="nc">UserRecord</span> <span class="o">{</span>
 
         <span class="kd">private</span> <span class="kt">int</span> <span class="n">userid</span><span class="o">;</span>
@@ -153,8 +167,8 @@
 <span class="n">JsonFactory</span><span class="o">.</span><span class="na">root</span><span class="o">().</span><span class="na">register</span><span class="o">(</span><span class="n">java</span><span class="o">.</span><span class="na">io</span><span class="o">.</span><span class="na">File</span><span class="o">.</span><span class="kd">class</span><span class="o">,</span> <span class="n">FileSimpleCoder</span><span class="o">.</span><span class="na">instance</span><span class="o">);</span>
 
 <span class="n">BsonFactory</span><span class="o">.</span><span class="na">root</span><span class="o">().</span><span class="na">register</span><span class="o">(</span><span class="n">java</span><span class="o">.</span><span class="na">io</span><span class="o">.</span><span class="na">File</span><span class="o">.</span><span class="kd">class</span><span class="o">,</span> <span class="n">FileSimpleCoder</span><span class="o">.</span><span class="na">instance</span><span class="o">);</span>
-    </pre></div>
-            
+                </pre></div>
+
             <h3><a id="welcome-to-github-pages" class="anchor" href="#" aria-hidden="true"><span class="octicon octicon-link"></span></a>BSON的协议格式</h3>
             <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;BSON类似Java自带的Serializable， 其格式如下: <br/>
                 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;1). 基本数据类型: 直接转换成byte[] <br/>