新增章节 1_4

+YUCHENG HU+


git-svn-id: https://svn.code.sf.net/p/hawebs/svn@509 a2543c7e-f6e9-4f8a-8bff-1ffc34733512

hadocs/java/trunk/src/code_conventions/code_conventions.ditamap

@@ -63,5 +63,7 @@
     <topicref href="tasks/chapter1/chapter1_1.dita"/>
     <topicref href="tasks/chapter1/chapter1_2.dita"/>
     <topicref href="tasks/chapter1/chapter1_3.dita"/>
+    <topicref href="tasks/chapter1/chapter1_4.dita"/>
+    <topicref href="tasks/chapter1/chapter1_5.dita"/>
   </topicref>
 </map>

hadocs/java/trunk/src/code_conventions/tasks/chapter1/chapter1_4.dita

@@ -0,0 +1,52 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- This document was created with Syntext Serna Free. --><!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd" []>
+<!-- 
+**
+ * Copyright (C) 2006-2010 YUCHENG HU
+ *
+ * +++++++++++++++++++++++++++++++++++++++++++++++++
+ * HA WEBSYSTEMS
+ * http://www.hawebs.net
+ * http://www.tcivis.com
+ *
+ * Contact
+ * huyuchengus@gmail.com / yuchenghu@hawebs.net
+ * 
+ * +++++++++++++++++++++++++++++++++++++++++++++++++
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ * GNU GENERAL PUBLIC LICENSE
+ * APACHE LICENSE, VERSION 2.0
+ *
+ * +++++++++++++++++++++++++++++++++++++++++++++++++
+-->
+
+<concept id="chapter1_4" xml:lang="zh">
+  <title>可读性</title>
+  <prolog>
+    <metadata>
+      <keywords>
+        <indexterm>Java</indexterm>
+        <indexterm>编码规范</indexterm>
+      </keywords>
+    </metadata>
+  </prolog>
+  <conbody>
+    <p><ol>
+        <li>避免使用不易理解的数字，用有意义的标识来替代。</li>
+        <li>不要使用难懂的技巧性很高的语句。</li>
+        <li>源程序中关系较为紧密的代码应尽可能相邻。</li>
+      </ol></p>
+  </conbody>
+</concept>

hadocs/java/trunk/src/code_conventions/tasks/chapter1/chapter1_5.dita

@@ -0,0 +1,51 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!-- This document was created with Syntext Serna Free. --><!DOCTYPE concept PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd" []>
+<!-- 
+**
+ * Copyright (C) 2006-2010 YUCHENG HU
+ *
+ * +++++++++++++++++++++++++++++++++++++++++++++++++
+ * HA WEBSYSTEMS
+ * http://www.hawebs.net
+ * http://www.tcivis.com
+ *
+ * Contact
+ * huyuchengus@gmail.com / yuchenghu@hawebs.net
+ * 
+ * +++++++++++++++++++++++++++++++++++++++++++++++++
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ * GNU GENERAL PUBLIC LICENSE
+ * APACHE LICENSE, VERSION 2.0
+ *
+ * +++++++++++++++++++++++++++++++++++++++++++++++++
+-->
+
+<concept id="chapter1_5" xml:lang="zh">
+  <title>性能</title>
+  <prolog>
+    <metadata>
+      <keywords>
+        <indexterm>Java</indexterm>
+        <indexterm>编码规范</indexterm>
+      </keywords>
+    </metadata>
+  </prolog>
+  <conbody>
+    <p>在写代码的时候，从头至尾都应该考虑性能问题。这不是说时间都应该浪费在优化代码上，而是我们时刻应该提醒自己要注意代码的效率。比如：如果没有时间来实现一个高效的算法，那么我们应该在文档中记录下来，以便在以后有空的时候再来实现她。 不是所有的人都同意在写代码的时候应该优化性能这个观点的，他们认为性能优化的问题应该在项目的后期再去考虑，也就是在程序的轮廓已经实现了以后。 </p>
+    <p>不要在循环中构造和释放对象。</p>
+    <p>使用 StringBuffer 对象。在处理 String 的时候要尽量使用 StringBuffer 类，StringBuffer 类是构成 String 类的基础。String 类将 StringBuffer 类封装了起来，（以花费更多时间为代价）为开发人员提供了一个安全的接口。当我们在构造字符串的时候，我们应该用 StringBuffer 来实现大部分的工作，当工作完成后将 StringBuffer 对象再转换为需要的 String 对象。比如：如果有一个字符串必须不断地在其后添加许多字符来完成构造，那么我们应该使用 StringBuffer 对象和她的 append() 方法。如果我们用 String 对象代替 StringBuffer 对象的话，会花费许多不必要的创建和释放对象的 CPU 时间。 </p>
+    <p>避免不必要的使用关键字 synchronized，应该在必要的时候再使用她，这是一个避免死锁的好方法。</p>
+  </conbody>
+</concept>