<%
List loanRecords = (List) request.getAttribute("loanRecords");
##if (loanRecords.size() > 0) {
%>
##
##
ID |
# #
Title |
##
Due date |
Fine |
<%
##for (int i = 0; i < loanRecords.size(); i++) {
LoanRecord loanRecord = (LoanRecord) loanRecords.get(i);
%>
">
<%=loanRecord.id%>
|
<%=loanRecord.title%>
|
<%=DateUtil.dateToString(loanRecord.dueDate)%>
|
<%=loanRecord.fine.toString()%>
|
<%
}
%>
<%
}
%>
下面则是Jasper所生成的代码。
package com.objectmentor.library.jsp.WEB_002dINF.pages.patrons.books;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import com.objectmentor.library.utils.DateUtil;
import com.objectmentor.library.web.controller.patrons.LoanRecord;
import java.util.List;
public final class loanRecords_jsp extends org.apache.jasper.runtime.HttpJspBase
implements org.apache.jasper.runtime.JspSourceDependent {
private static java.util.List _jspx_dependants;
public Object getDependants() {
return _jspx_dependants;
}
public void _jspService(HttpServletRequest request, HttpServletResponse response)
throws java.io.IOException, ServletException {
JspFactory _jspxFactory = null;
PageContext pageContext = null;
HttpSession session = null;
ServletContext application = null;
ServletConfig config = null;
JspWriter out = null;
Object page = this;
JspWriter _jspx_out = null;
PageContext _jspx_page_context = null;
try {
_jspxFactory = JspFactory.getDefaultFactory();
response.setContentType("text/html");
pageContext = _jspxFactory.getPageContext(this, request, response,
null, true, 8192, true);
_jspx_page_context = pageContext;
application = pageContext.getServletContext();
config = pageContext.getServletConfig();
session = pageContext.getSession();
out = pageContext.getOut();
_jspx_out = out;
out.write('/n');
out.write('/n');
out.write('/n');
List loanRecords = (List) request.getAttribute("loanRecords");
if (loanRecords.size() > 0) {
out.write("/n");
out.write("/n");
out.write(" /n");
out.write("
ID | /n");
out.write("
Title | /n");
out.write("
Due date | /n");
out.write("
Fine | /n");
out.write("
/n");
out.write(" ");
for (int i = 0; i < loanRecords.size(); i++) {
LoanRecord loanRecord = (LoanRecord) loanRecords.get(i);
out.write("/n");
out.write(" out.print(i%2==0?"even":"odd");
out.write("/">/n");
out.write("
");
out.print(loanRecord.id);
out.write("/n");
out.write(" | /n");
out.write("
");
out.print(loanRecord.title);
out.write("/n");
out.write(" | /n");
out.write("
");
out.print(DateUtil.dateToString(loanRecord.dueDate));
out.write("/n");
out.write(" | /n");
out.write("
");
out.print(loanRecord.fine.toString());
out.write("/n");
out.write(" | /n");
out.write("
/n");
out.write(" ");
}
out.write("/n");
out.write("
/n");
}
} catch (Throwable t) {
if (!(t instanceof SkipPageException)){
out = _jspx_out;
if (out != null && out.getBufferSize() != 0)
out.clearBuffer();
if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);
if (_jspxFactory != null) _jspxFactory.releasePageContext(_jspx_page_context);
}
}
}
##Final Complaint
#Why should this class be declared final? What if I want to create a test stub derived class? Why would anyone find a generated class so offensive that I can't even override it?
If you read this code carefully, you will find that to use this servlet instance we need HttpServletRequest and HttpServletResponse instance.
If we study it more carefully, we will find that the servlet writes all HTML to the instance of JspWriter, and JspWriter is obtained from the PageContext. If we could create a mock up version of the JspWriter to hold all this HTML, and then create a mock up version of the PageContext to dispatch the mock JspWriter, then we would be able to access this HTML in our tests.
Fortunately, the designers of Tomcat put the creation of JspWriter into the factory class of JspFactory. And this factory class can be overridden! This means that we can get our own JspWriter class in the servlet without changing the servlet. All you need is the following code.
#class MockJspFactory extends JspFactory {
public PageContext getPageContext(Servlet servlet, ServletRequest servletRequest, ServletResponse servletResponse, String string, boolean b, int i, boolean b1) {
return new MockPageContext(new MockJspWriter());
##}
public void releasePageContext(PageContext pageContext) {
##}
public JspEngineInfo getEngineInfo() {
##return null;
##}
##}
Now, what we need is mock Jspwriter. For ease of presentation, I used the following:
##MockJspWriter
package com.objectmentor.library.web.framework.mocks;
##import javax.servlet.jsp.JspWriter;
import java.io.IOException;
#public class MockJspWriter extends JspWriter {
##private StringBuffer submittedContent;
##public MockJspWriter(int bufferSize, boolean autoFlush) {
##super(bufferSize, autoFlush);
submittedContent = new StringBuffer();
}
public String getContent() {
##return submittedContent.toString();
}
##public void print(String arg0) throws IOException {
submittedContent.append(arg0);
##}
##public void write(char[] arg0, int arg1, int arg2) throws IOException {
for (int i=0; i## submittedContent.append(String.valueOf (arg0[arg1++]));
}
public void write(String content) throws IOException {
##submittedContent.append(content);
}
#// lots of uninteresting methods elied. I just gave them
##// degenerate implementations. (e.g. {})
}
No need to care about the unimplemented methods that I omitted, I think you only need to care about those Just enough to make my tests run. For the rest, I'll just use its degenerate implementation.
My IDE is very helpful in creating these mock classes. It can automatically build method prototypes and provide degenerate implementations for methods that need to be implemented by interfaces or abstract classes.
Similarly create the MockPageContext, MockHttpServletRequest and MockHttpServletResponse classes using similar methods.
##MockPageContext
package com.objectmentor.library.web.framework .mocks;
##import javax.servlet.*;##import javax.servlet .http.*;
import javax.servlet.jsp.*;
import java.io.IOException;
import java.util.Enumeration;
##public class MockPageContext extends PageContext {
private final JspWriter out;
##private HttpServletRequest request ;
public MockPageContext(JspWriter out) {
this.out = out;
request = new MockHttpServletRequest();
}
##public JspWriter getOut() {
return out;
}
public ServletRequest getRequest() {##return request;
}
// lots of degenerate functions elided.
}
MockHttpServletRequest
package com.objectmentor.library.web.framework.mocks;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.security.Principal;
import java.util.*;
public class MockHttpServletRequest implements HttpServletRequest {
private String method;
private String contextPath;
private String requestURI;
private HttpSession session = new MockHttpSession();
private Map parameters = new HashMap();
private Map attributes = new HashMap();
public MockHttpServletRequest(String method, String contextPath,
String requestURI) {
super();
this.method = method;
this.contextPath = contextPath;
this.requestURI = requestURI;
}
public MockHttpServletRequest() {
this("GET");
}
public MockHttpServletRequest(String method) {
this(method, "/Library", "/Library/foo/bar.jsp");
}
public String getContextPath() {
return contextPath;
}
public String getMethod() {
return method;
}
public String getRequestURI() {
return requestURI;
}
public String getServletPath() {
return requestURI.substring(getContextPath().length());
}
public HttpSession getSession() {
return session;
}
public HttpSession getSession(boolean arg0) {
return session;
}
public Object getAttribute(String arg0) {
return attributes.get(arg0);
}
public String getParameter(String arg0) {
return (String) parameters.get(arg0);
}
public Map getParameterMap() {
return parameters;
}
public Enumeration getParameterNames() {
return null;
}
public void setSession(HttpSession session) {
this.session = session;
}
public void setParameter(String s, String s1) {
parameters.put(s, s1);
}
public void setAttribute(String name, Object value) {
attributes.put(name, value);
}
// Lots of degenerate methods elided.
}
MockHttpServletResponse
package com.objectmentor.library.web.framework.mocks;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.*;
import java.io.*;
import java.util.Locale;
public class MockHttpServletResponse implements HttpServletResponse {
// all functions are implemented to be degenerate.
}
有了这些mock对象，现在我就可以创建一个loanRecords_jsp的servlet实例并且开始调用它！我的头一个测试用例就像下面这样：
public void testSimpleTest() throws Exception {Copy after login
MockJspWriter jspWriter = new MockJspWriter();
Copy after login
MockPageContext pageContext = new MockPageContext(jspWriter);
Copy after login
JspFactory.setDefaultFactory(new MockJspFactory(pageContext));
Copy after login
HttpJspBase jspPage = new loanRecords_jsp();
Copy after login
Copy after login
HttpServletRequest request = new MockHttpServletRequest();
Copy after login
HttpServletResponse response = new MockHttpServletResponse();
Copy after login
jspPage._jspInit();
Copy after login
Copy after login
jspPage._jspService(request, response);
Copy after login
assertEquals("", jspWriter.getContent());Copy after login
就像预期的一样，测试失败了。这是因为还有些内容还没补充上，不过所剩无多。如果你仔细的看过Jsp文件，你就会发现它调用了request.getAttribute(“loanRecords”)并且期望返回一个List。但因为目前的测试并未为这样的属性赋值，从而导致了代码抛出了异常。
要想成功让servlet输出HTML，我们还需要加载这个属性。然后，我们就可以使用HtmlUnit来解析此HTML并且编写相应的单元测试。
HtmlUnit非常的容易使用，尤其是在测试所产生的像是本例这样的web pages上。我这里还有篇文章详细的介绍了它。
下面就是最终测试加载属性的测试，它通过htmlunit来检测HTML，并且做出正确的判断：
package com.objectmentor.library.jspTest.books.patrons.books;
Copy after login
import com.gargoylesoftware.htmlunit.*;
Copy after login
import com.gargoylesoftware.htmlunit.html.*;
Copy after login
import com.objectmentor.library.jsp.WEB_002dINF.pages.patrons.books.loanRecords_jsp;
Copy after login
import com.objectmentor.library.utils.*;
Copy after login
import com.objectmentor.library.web.controller.patrons.LoanRecord;
Copy after login
import com.objectmentor.library.web.framework.mocks.*;
Copy after login
import junit.framework.TestCase;
Copy after login
import org.apache.jasper.runtime.HttpJspBase;
Copy after login
import javax.servlet.*;
Copy after login
import javax.servlet.http.*;
Copy after login
import javax.servlet.jsp.*;
Copy after login
import java.util.*;
Copy after login
public class LoanRecordsJspTest extends TestCase {Copy after login
private MockPageContext pageContext;
Copy after login
private MockJspWriter jspWriter;
Copy after login
private JspFactory mockFactory;
Copy after login
private MockHttpServletResponse response;
Copy after login
private MockHttpServletRequest request;
Copy after login
private WebClient webClient;
Copy after login
private TopLevelWindow dummyWindow;
Copy after login
protected void setUp() throws Exception {Copy after login
jspWriter = new MockJspWriter();
Copy after login
pageContext = new MockPageContext(jspWriter);
Copy after login
mockFactory = new MockJspFactory(pageContext);
Copy after login
JspFactory.setDefaultFactory(mockFactory);
Copy after login
response = new MockHttpServletResponse();
Copy after login
request = new MockHttpServletRequest();
Copy after login
webClient = new WebClient();
Copy after login
webClient.setJavaScriptEnabled(false);
Copy after login
dummyWindow = new TopLevelWindow("", webClient);Copy after login
public void testLoanRecordsPageGeneratesAppropriateTableRows() throws Exception {Copy after login
HttpJspBase jspPage = new loanRecords_jsp();
Copy after login
Copy after login
jspPage._jspInit();
Copy after login
Copy after login
List<LoanRecord> loanRecords = new ArrayList<LoanRecord>();<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false"> addLoanRecord(loanRecords,
Copy after login
Copy after login
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