Action中获取HttpServletResponse ,HttpServletRequest,HttpSession等Servlet相关变量有两种方式；
1、非Ioc方式
要获得上述对象，关键Struts 2.0中com.opensymphony.xwork2.ActionContext类。我们可以通过它的静态方法getContext()获取当前Action的上下文对象。 另外，org.apache.struts2.ServletActionContext作为辅助类（Helper Class），可以帮助您快捷地获得这几个对象。
HttpServletRequest request = ServletActionContext.getRequest();
HttpServletResponse response = ServletActionContext.getResponse();
HttpSession session = request.getSession();
2、Ioc 方式
只要Action类实现SessionAware, ServletRequestAware, ServletResponseAware这几个接口，相应的变量会自动注入
调用action的方法
我们知道，当客户端请求一个action时，会生成一个Action 对应的变量，并执行execute方法，但这是需要跟据配置来确定的
< action name ="HelloWorld" class ="tutorial.HelloWorld" >
< result > /HelloWorld.jsp </ result >
</ action > 要想改变默认执行的方法，需要在action节点加上要调用的方法名，如:
<action name="AliasHelloWorld" class="tutorial.HelloWorld" method="aliasAction">
<result>/HelloWorld.jsp</result>
</action>
如果要实现类似于Structs1.x那样的DispatchAction方式的调用，配置例子如下：
<action name="login!*" method="{1}" class="one.LoginAction">
<result name="success" type="dispatcher">
<param name="location">/main.jsp</param>
</result>
<result name="input">/login.jsp</result>
<result name="loginfail" type="dispatcher">
<param name="location">/login.jsp</param>
</result>
</action> 如上配置，如果只调用login.action，会执行默认方法execute()。
Structs 2文件上传例子
package one;
import java.io.File;
import java.text.*;
import java.util.*;
import javax.servlet.ServletContext;
import org.apache.commons.io.FileUtils;
import org.apache.struts2.util.ServletContextAware;
import com.opensymphony.xwork2.ActionSupport;
public class FileUploadAction extends ActionSupport implements ServletContextAware{
private File doc;
private String docContentType;
private String docFileName;
private ServletContext context;
public String execute()throws Exception{
String target=context.getRealPath("/upload");
String file=generateFileName(docFileName);
File dfile=new File(target,file);
FileUtils.copyFile(doc,dfile);
return this.SUCCESS;
}
private String generateFileName(String fileName) {
DateFormat format = new SimpleDateFormat("yyMMddHHmmss");
String formatDate = format.format(new Date());
int random = new Random().nextInt(10000);
int position = fileName.lastIndexOf(".");
String extension = fileName.substring(position);
return formatDate + random + extension;
}
public void setServletContext(ServletContext context) {
// TODO Auto-generated method stub
this.context=context;
}
public ServletContext getContext() {
return context;
}
public void setContext(ServletContext context) {
this.context = context;
}
public File getDoc() {
return doc;
}
public void setDoc(File doc) {
this.doc = doc;
}
public String getDocContentType() {
return docContentType;
}
public void setDocContentType(String docContentType) {
this.docContentType = docContentType;
}
public String getDocFileName() {
return docFileName;
}
public void setDocFileName(String docFileName) {
this.docFileName = docFileName;
}
}
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