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 <span id="Label3"><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>1.</strong> Struts2的类型转换，对于8个原生数据类型以及Date，String等常见类型，Struts2可以使用内建的类型转换器实现自动的转换；但对于自定义的类型转换来说，</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; 就需要我们自己指定类型转器的方式。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>2.</strong> 类型转换器必须继承DefaultTypeConverter，一般继承它的子类StrutsTypeConverter。action中调用set和get方法时，调用类型转换方法。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>3.</strong> 自定义类型转换器的实现步骤：</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; 1). 继承StrutsTypeConverter</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; 2). 覆盖convertFromString和convertToString</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;范例：</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp;public class UtilDateConverter extends StrutsTypeConverter {</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; private static final String PATTERN = "yyyy/MM/dd";</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //浏览器提交到服务器是调用，将字符串转换成对象</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Override</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;public Object convertFromString(Map context, String[] values, Class toClass) {</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; //values为要转换属性的数组，可能有多个名字相同，所以取第一个。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;String dateString = values[0];</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;SimpleDateFormat sdf = new SimpleDateFormat(PATTERN);</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;Date date = null;</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;try {</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;//字符串，转换成日期类型。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;date = sdf.parse(dateString);</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;} catch (ParseException e) {</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;e.printStackTrace();</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return date;</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;}</span></p><p><span style="font-family: ‘Microsoft YaHei‘;"> <br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;//服务器向浏览器输出时调用，将某种类型转换成字符串。o是要转换成字符串的对象。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; @Override</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;public String convertToString(Map context, Object o) {</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Date date = (Date)o;</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; return new SimpleDateFormat("yyyy年MM月dd日").format(date);</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;}<br /> <br />&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; }<br />&nbsp; &nbsp; &nbsp; &nbsp; 3).注册类型转换器</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; a).局部类型转换器，局部类型转换器只对当前Action起作用，需要提供如下配置文件：</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; MyActionName-conversion.properties,MyActionName指需要使用转换器的Action名称&rdquo;-conversion.properties&ldquo;固定字符串，不能修改。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 我们AddUserAction类型转换器的配置文件名称为：AddUserAction-conversion.properties,该配置文件必须和Action放到同一个目录中，该配</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 置文件的格式为：Action中的属性名称=转换器的完整路径，如：birthday=com.bjpowernode.struts2.UtilDateConverter&nbsp;也可以转换数组，</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 同样需要有set和get方法。 </span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;b).全局类型转换器，全局类型转换器可以对所有的Action起作用（同Struts1的类型转换器），需要提供如下配置文件：</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;xwork-conversion.properties(该名字固定),该配置文件需要放到src下，该配置文件的格式：需要转换的类型完整路径=转换器的完整路径，</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;如：java.util.Date=com.bjpowernode.struts2.UtilDateConverter自定义类型也可以转换。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; 补：请求页面：</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;出生日期：&lt;input type="text" name="birthday"&gt;&lt;br&gt;</span></p><p><span style="font-family: ‘Microsoft YaHei‘;">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;显示页面：&lt;s:property value="http://www.mamicode.com/birthday"/&gt; 或 &lt;s:text name="date"&gt;&lt;/s:text&gt;</span></p><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>4.</strong> 如果全局类型转换器和局部类型转换器同时存在，局部优先。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>5.</strong> 采用struts2标签读取属性get方法时可以调用转换器的convertToString。采用JSTL不会调用，显示的是默认格式的时间。</span></p><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>6.</strong> 类型转换时，若发生异常，fieldError中会自动把异常加上,英文的。 </span></p><p><span style="font-family: ‘Microsoft YaHei‘;"><strong>7.</strong> 使用类型转换器须要在Action中提供属性的set和get方法</span></p><p>struts(类型转换器)</p></span>