struts2中常用Result类型type的用法

<result-types>
<result-type name="chain" class="com.opensymphony.xwork2.ActionChainResult"/>
<result-type name="dispatcher" class="org.apache.struts2.dispatcher.ServletDispatcherResult" default="true"/>
<result-type name="freemarker" class="org.apache.struts2.views.freemarker.FreemarkerResult"/>
<result-type name="httpheader" class="org.apache.struts2.dispatcher.HttpHeaderResult"/>
<result-type name="redirect" class="org.apache.struts2.dispatcher.ServletRedirectResult"/>
<result-type name="redirectAction" class="org.apache.struts2.dispatcher.ServletActionRedirectResult"/>
<result-type name="stream" class="org.apache.struts2.dispatcher.StreamResult"/>
<result-type name="velocity" class="org.apache.struts2.dispatcher.VelocityResult"/>
<result-type name="xslt" class="org.apache.struts2.views.xslt.XSLTResult"/>
<result-type name="plainText" class="org.apache.struts2.dispatcher.PlainTextResult" />
</result-types>

1.chain
该类型是请求转发给其他的action，如果为jsp则会报错

需要注意的就是与redirect的区别，请求转发是还在当前请求，

而redirect会响应一次浏览器然后浏览器再根据响应请求重定向的资源，注意看url的变化就明白了！

下面是apache给的示例，这个比较简单，没什么说的，

<span class="code-tag"></span><div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><strong>[html]</strong> <a target=_blank class="ViewSource" title="view plain" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">view plain</a><a target=_blank class="CopyToClipboard" title="copy" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">copy</a></div></div><ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span class="tag-name">package</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"public"</span><span> </span><span class="attribute">extends</span><span>=</span><span class="attribute-value">"struts-default"</span><span class="tag">></span><span>  </span></span></li><li><span>    </span><span class="comments"><!-- Chain creatAccount to login, using the default parameter --></span><span>  </span></li><li class="alt"><span>    </span><span class="tag"><</span><span class="tag-name">action</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"createAccount"</span><span> </span><span class="attribute">class</span><span>=</span><span class="attribute-value">"..."</span><span class="tag">></span><span>  </span></li><li><span>        </span><span class="tag"><</span><span class="tag-name">result</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"chain"</span><span class="tag">></span><span>login</span><span class="tag"></</span><span class="tag-name">result</span><span class="tag">></span><span>  </span></li><li class="alt"><span>    </span><span class="tag"></</span><span class="tag-name">action</span><span class="tag">></span><span>  </span></li><li><span>  </span></li><li class="alt"><span>    </span><span class="tag"><</span><span class="tag-name">action</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"login"</span><span> </span><span class="attribute">class</span><span>=</span><span class="attribute-value">"..."</span><span class="tag">></span><span>  </span></li><li><span>        </span><span class="comments"><!-- Chain to another namespace --></span><span>  </span></li><li class="alt"><span>        </span><span class="tag"><</span><span class="tag-name">result</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"chain"</span><span class="tag">></span><span>  </span></li><li><span>            </span><span class="tag"><</span><span class="tag-name">param</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"actionName"</span><span class="tag">></span><span>dashboard</span><span class="tag"></</span><span class="tag-name">param</span><span class="tag">></span><span>  </span></li><li class="alt"><span>            </span><span class="tag"><</span><span class="tag-name">param</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"namespace"</span><span class="tag">></span><span>/secure</span><span class="tag"></</span><span class="tag-name">param</span><span class="tag">></span><span>  </span></li><li><span>        </span><span class="tag"></</span><span class="tag-name">result</span><span class="tag">></span><span>  </span></li><li class="alt"><span>    </span><span class="tag"></</span><span class="tag-name">action</span><span class="tag">></span><span>  </span></li><li><span></span><span class="tag"></</span><span class="tag-name">package</span><span class="tag">></span><span>  </span></li><li class="alt"><span>  </span></li><li><span></span><span class="tag"><</span><span class="tag-name">package</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"secure"</span><span> </span><span class="attribute">extends</span><span>=</span><span class="attribute-value">"struts-default"</span><span> </span><span class="attribute">namespace</span><span>=</span><span class="attribute-value">"/secure"</span><span class="tag">></span><span>  </span></li><li class="alt"><span>    </span><span class="tag"><</span><span class="tag-name">action</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"dashboard"</span><span> </span><span class="attribute">class</span><span>=</span><span class="attribute-value">"..."</span><span class="tag">></span><span>  </span></li><li><span>        </span><span class="tag"><</span><span class="tag-name">result</span><span class="tag">></span><span>dashboard.jsp</span><span class="tag"></</span><span class="tag-name">result</span><span class="tag">></span><span>  </span></li><li class="alt"><span>    </span><span class="tag"></</span><span class="tag-name">action</span><span class="tag">></span><span>  </span></li><li><span></span><span class="tag"></</span><span class="tag-name">package</span><span class="tag">></span><span>  </span></li></ol></div>
<strong><span style="font-size:16px;">2.dispatcher</span></strong>
请求转发视图资源，比如jsp,html，如果请求action会找不到资源，
请求转发的问题看1中的说明
apache给的示例。。也没啥说的
<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><strong>[html]</strong> <a target=_blank class="ViewSource" title="view plain" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">view plain</a><a target=_blank class="CopyToClipboard" title="copy" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">copy</a></div></div><ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span class="tag-name">result</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"success"</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"dispatcher"</span><span class="tag">></span><span>  </span></span></li><li><span>  </span><span class="tag"><</span><span class="tag-name">param</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"location"</span><span class="tag">></span><span>foo.jsp</span><span class="tag"></</span><span class="tag-name">param</span><span class="tag">></span><span>  </span></li><li class="alt"><span></span><span class="tag"></</span><span class="tag-name">result</span><span class="tag">></span><span>  </span></li></ol></div>
<strong><span style="font-size:16px;">3.httpheader</span></strong>
这个挺有意思的，可以随便更改响应状态
比如下面的这个示例
<div class="dp-highlighter bg_html"><div class="bar"><div class="tools"><strong>[html]</strong> <a target=_blank class="ViewSource" title="view plain" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">view plain</a><a target=_blank class="CopyToClipboard" title="copy" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">copy</a></div></div><ol class="dp-xml"><li class="alt"><span><span class="tag"><</span><span class="tag-name">action</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"test"</span><span> </span><span class="attribute">class</span><span>=</span><span class="attribute-value">"com.iss.action.TestAction"</span><span class="tag">></span><span>  </span></span></li><li><span>        </span><span class="tag"><</span><span class="tag-name">result</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"success"</span><span> </span><span class="attribute">type</span><span>=</span><span class="attribute-value">"httpheader"</span><span class="tag">></span><span>  </span></li><li class="alt"><span>        </span><span class="tag"><</span><span class="tag-name">param</span><span> </span><span class="attribute">name</span><span>=</span><span class="attribute-value">"status"</span><span class="tag">></span><span>400</span><span class="tag"></</span><span class="tag-name">param</span><span class="tag">></span><span>  </span></li><li><span>    </span><span class="tag"></</span><span class="tag-name">result</span><span class="tag">></span><span>  </span></li><li class="alt"><span>    </span><span class="tag"></</span><span class="tag-name">action</span><span class="tag">></span><span>  </span></li></ol></div>
当action返回SUCCESS的时候，会将响应状态修改为400，客户端错误的请求，
还有其他的状态可以自行尝试，比如为100时，浏览器会在请求一段时间之后继续当前页面，500则为服务器内部错误等等
具体为什么会产生这样的结果，当然得把源码翻出来了
下面是HttpHeaderResult的一些成员变量，private的可以作为param的name属性
<div class="dp-highlighter bg_java"><div class="bar"><div class="tools"><strong>[java]</strong> <a target=_blank class="ViewSource" title="view plain" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">view plain</a><a target=_blank class="CopyToClipboard" title="copy" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">copy</a></div></div><ol class="dp-j"><li class="alt"><span><span class="keyword">private</span><span> </span><span class="keyword">static</span><span> </span><span class="keyword">final</span><span> </span><span class="keyword">long</span><span> serialVersionUID = 195648957144219214L;  </span></span></li><li><span>  </span></li><li class="alt"><span></span><span class="comment">/** The default parameter */</span><span>  </span></li><li><span></span><span class="keyword">public</span><span> </span><span class="keyword">static</span><span> </span><span class="keyword">final</span><span> String DEFAULT_PARAM = </span><span class="string">"status"</span><span>;  </span></li><li class="alt"><span>  </span></li><li><span>  </span></li><li class="alt"><span></span><span class="keyword">private</span><span> </span><span class="keyword">boolean</span><span> parse = </span><span class="keyword">true</span><span>;  </span></li><li><span></span><span class="keyword">private</span><span> Map<String,String> headers;  </span></li><li class="alt"><span></span><span class="keyword">private</span><span> </span><span class="keyword">int</span><span> status = -</span><span class="number">1</span><span>;  </span></li><li><span></span><span class="keyword">private</span><span> </span><span class="keyword">int</span><span> error = -</span><span class="number">1</span><span>;  </span></li><li class="alt"><span></span><span class="keyword">private</span><span> String errorMessage;  </span></li></ol></div>
下面是具体执行操作过程，可以看到response.setStatus等操作

<div class="dp-highlighter bg_java"><div class="bar"><div class="tools"><strong>[java]</strong> <a target=_blank class="ViewSource" title="view plain" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">view plain</a><a target=_blank class="CopyToClipboard" title="copy" href="http://blog.csdn.net/zhouyuqwert/article/details/6765926#">copy</a></div></div><ol class="dp-j"><li class="alt"><span><span class="keyword">public</span><span> </span><span class="keyword">void</span><span> execute(ActionInvocation invocation) </span><span class="keyword">throws</span><span> Exception {  </span></span></li><li><span>        HttpServletResponse response = ServletActionContext.getResponse();  </span></li><li class="alt"><span>        ValueStack stack = ActionContext.getContext().getValueStack();  </span></li><li><span>          </span></li><li class="alt"><span>        </span><span class="keyword">if</span><span> (status != -</span><span class="number">1</span><span>) {  </span></li><li><span>            response.setStatus(status);  </span></li><li class="alt"><span>        } </span><span class="keyword">else</span><span> </span><span class="keyword">if</span><span> (error != -</span><span class="number">1</span><span>) {  </span></li><li><span>            </span><span class="keyword">if</span><span> (errorMessage != </span><span class="keyword">null</span><span>) {  </span></li><li class="alt"><span>                String finalMessage = parse ? TextParseUtil.translateVariables(  </span></li><li><span>                    errorMessage, stack) : errorMessage;  </span></li><li class="alt"><span>                response.sendError(error, finalMessage);  </span></li><li><span>            } </span><span class="keyword">else</span><span>  </span></li><li class="alt"><span>                response.sendError(error);  </span></li><li><span>        }  </span></li><li class="alt"><span>  </span></li><li><span>        </span><span class="keyword">if</span><span> (headers != </span><span class="keyword">null</span><span>) {  </span></li><li class="alt"><span>            </span><span class="keyword">for</span><span> (Iterator iterator = headers.entrySet().iterator();  </span></li><li><span>                 iterator.hasNext();) {  </span></li><li class="alt"><span>                Map.Entry entry = (Map.Entry) iterator.next();  </span></li><li><span>                String value = (String) entry.getValue();  </span></li><li class="alt"><span>                String finalValue = parse ? TextParseUtil.translateVariables(value, stack) : value;  </span></li><li><span>                response.addHeader((String) entry.getKey(), finalValue);  </span></li><li class="alt"><span>            }  </span></li><li><span>        }  </span></li><li class="alt"><span>    }  </span></li></ol></div>
<strong><span style="font-size:16px;">4.redirect
</span></strong>

重定向操作，与请求转发的区别看1的介绍

让客户端请求另外的网络资源，可以为action，也可以为视图资源

下面是apache的示例

[html]
view plaincopy

<result name="success" type="redirect">
<param name="location">foo.jsp</param>
<param name="parse">false</param>
</result>

5.redirectAction
重定向至Action，与redirect的区别找了好久，但是也没发现比较权威的说明

最明显的区别当然是redirectAction只能请求action,如果请求视图资源会报错

然后还有个小区别就是redirectAction会为url添加.action后缀而redirect不会

有说redirectAction无法通过url传参，但是我测试时完全可以通过request获取到，

此处区别如果有哪位知道的麻烦告知，Thank you!

下面是apache的传参的示例

[html]
view plaincopy

<package name="passingRequestParameters" extends="struts-default" namespace="/passingRequestParameters">
<-- Pass parameters (reportType, width and height) -->
<!--
The redirect-action url generated will be :
/genReport/generateReport.action?reportType=pie&width=100&height=100
-->
<action name="gatherReportInfo" class="...">
<result name="showReportResult" type="redirect-action">
<param name="actionName">generateReport</param>
<param name="namespace">/genReport</param>
<param name="reportType">pie</param>
<param name="width">100</param>
<param name="height">100</param>
</result>
</action>
</package>

6.stream
这个返回类型主要用作下载文件或者在浏览器上显示PDF等文档

此处给一个显示PDF文档示例

项目web.xml中

[html]
view plaincopy

<mime-mapping>
<extension>pdf</extension>
<mime-type>application/pdf</mime-type>
</mime-mapping>

struts.xml中

[html]
view plaincopy

<action name="test" class="com.iss.action.TestAction">
<result name="success" type="stream">
<param name="contentType">application/pdf</param>
<param name="inputName">inputStream</param>
<param name="contentDisposition">filename="a.pdf"</param>
</result>
</action>

TestAction.java中

[java]
view plaincopy

public class TestAction extends ActionSupport
{

private InputStream inputStream;

public InputStream getInputStream()
{
return inputStream;
}

@Override
public String execute() throws Exception
{
inputStream = new FileInputStream("xxxxx/a.pdf");//要下载或显示的文件路径
return SUCCESS;
}
}

需要注意的地方是struts.xml中inputName的值要与TestAction中的get方法名相关，如在此处是getInputStream，inputName则为inputStream

7.plainText

响应以plain形式返回给客户端

截取源码的最重要的一部分

[java]
view plaincopy

if (charset != null) {
response.setContentType("text/plain; charset="+charSet);
}
else {
response.setContentType("text/plain");
}

8.freemarker,velocity,xslt