How can we display dynamic or static images that can be provided as an array of bytes
To display an image represented as an array of bytes
- Reference an Action for the image src attribute
- Provide a helper method on the Action to return an array of bytes
- Provide a Result Type that renders the array to the response
Reference an Action
MyAction.jsp
<img src="/myWebAppContext/myAction.do" />
Provide Helper Methods
MyAction.java
public class MyAction extends ActionSupport {
public String doDefault() {
return "myImageResult";
}
public byte[] getMyImageInBytes() { .... }
public String getMyContentType() { ... }
public String getMyContentDisposition() { ... }
public int getMyContentLength() { .... }
public int getMyBufferSize() { ... }
}
Provide a Custom Result Type
struts.xml
<struts> ... <result-types> <result-type name="myBytesResult" class="MyBytesResult" /> </result-types> ... <action name="myAction" class="MyAction"> <result name="myImageResult" type="myBytesResult"> <param name="contentType">${myContentType}</param> <param name="contentDisposition">${myContentDisposition}</param> <param name="contentLength">${myContentLength}</param> <param name="bufferSize">${myBufferSize}</param> <result> </action> ... </struts>
MyBytesResult.java
public class MyBytesResult implements Result {
public void execute(ActionInvocation invocation) throws Exception {
MyAction action = (MyAction) invocation.getAction();
HttpServletResponse response = ServletActionContext.getResponse();
response.setContentType(action.getContentType());
response.setContentLength(action.getContentLength());
response.getOutputStream().write(action.getImageInBytes());
response.getOutputStream().flush();
}
}
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