spagobi 引擎调用，跨web应用访问，filter的使用
一、前言
spagobi的引擎都是模块方式加载的，引擎就是一个web app，比如SpagoBITalendEngine。spagobi门户传递一个document id给talend engine应用，在filter层初始化session，在业务servlet，即对外开放的服务访问点，从request session获取相关信息，并execute talend job。
本文根据以上应用，来作一个简化的模型：
1、两个web app，其中一个访问另一个的servelt
2、servlet在执行前，在filter类里初始化session，仅是设置一个attribute。（处理结果写入log日志）
3、在servlet里取到attribute，并返回到页面。（处理结果写入log日志）
附：未模拟单点登录。
二、环境准备
jvm: j2sdk 1.6
web: tomcat 6.0
三、开发
（1）创建两个“dynamic web project”
名称分别为：biweb（主调web app）和biwebengine（被调web app），当然你要先配置好它的web server为tomcat
（2）开发biwebengine
－创建类filters.AccessFilter
package filters;
import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import org.apache.log4j.Logger;
public class AccessFilter implements Filter {
??? public final String DOCUMENT_ID_PARAM_NAME = "document";
??? private static transient Logger logger = Logger
??????????? .getLogger(AccessFilter.class);
??? @Override
??? public void destroy() {
??????? // TODO Auto-generated method stub
??? }
??? @Override
??? public void doFilter(ServletRequest request, ServletResponse response,
??????????? FilterChain chain) throws IOException, ServletException {
??????? String documentId;
??????? documentId = (String) request.getParameter(DOCUMENT_ID_PARAM_NAME);
??????? logger.info("Filter documentId from request: " + documentId);
???????
??????? if (request instanceof HttpServletRequest) {
??????????? ((HttpServletRequest) request).getSession().setAttribute(DOCUMENT_ID_PARAM_NAME, documentId);
??????? }
??????? chain.doFilter(request, response); //for other filters
??? }
??? @Override
??? public void init(FilterConfig arg0) throws ServletException {
??????? // TODO Auto-generated method stub
??? }
}
－servlet类de.daniel.RunService
package de.daniel;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.Logger;
public class RunService extends HttpServlet{
??? private static final long serialVersionUID = 1L;
??? private static transient Logger logger = Logger.getLogger(RunService.class);
??? public final String DOCUMENT_ID_PARAM_NAME = "document";
?
??? @Override
??? protected void service(HttpServletRequest request, HttpServletResponse response)
??????????? throws ServletException, IOException {
???????
??????? String documentId? = String.valueOf(request.getSession().getAttribute(DOCUMENT_ID_PARAM_NAME));
??????? logger.info("RunService has gotten attribute from session: " + documentId);
???????
??????? // setup response header
??????? if(response instanceof HttpServletResponse) {
??????????? ((HttpServletResponse)response).setHeader("Content-Disposition", "inline;filename=\"service-response\";");
??????? }
???????
??????? String content = "invoked sucessfully! " + DOCUMENT_ID_PARAM_NAME + " is: " + documentId;
???????
??????? response.setContentType("text/plain");
??????? response.setContentLength( content.length() );
???????
??????? if(response instanceof HttpServletResponse) {
??????????? ((HttpServletResponse)response).setStatus(200);
??????? }
???????
??????? response.getWriter().print(content);
??????? response.getWriter().flush();
??? }
??? @Override
??? public void init() throws ServletException {
??????? super.init();
??? }
}
－log4j日志配置log4j.properties
日志将被保存到tomcat/logs下的biwebengine.log文件
log4j.rootLogger=INFO, biwebengine
# SpagoBI Appender
log4j.appender.biwebengine=org.apache.log4j.RollingFileAppender
log4j.appender.biwebengine.File=${catalina.base}/logs/biwebengine.log
log4j.appender.biwebengine.MaxFileSize=10000KB
log4j.appender.biwebengine.MaxBackupIndex=0
log4j.appender.biwebengine.layout=org.apache.log4j.PatternLayout
log4j.appender.biwebengine.layout.ConversionPattern=%d{DATE} %5p %c.%M:%L - %m%n
－web.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app>
? <display-name>biwebengine</display-name>
? <filter>
<filter-name>Run Service Filter</filter-name>
<filter-class>filters.AccessFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>GBK</param-value>
</init-param>
??? </filter>
??? <filter-mapping>
??? <filter-name>Run Service Filter</filter-name>
??? <url-pattern>/RunService/*</url-pattern>
??? </filter-mapping>
??? <servlet>
??????????? <servlet-name>RunService</servlet-name>
??????????? <servlet-class>de.daniel.RunService</servlet-class>
??????? </servlet>
??? <servlet-mapping>
??????? <servlet-name>RunService</servlet-name>
??????? <url-pattern>/RunService</url-pattern>
??? </servlet-mapping>
</web-app>
（3）开发biweb
只要写一个首页index.jsp就可以了，其它也不用配置：
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
??? pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
??? <form name="form1" method="post" action="../biwebengine/RunService?document=11">
??????? <input type="submit" value="access biwebengine"/>
??? </form>
</body>
</html>
四、验证
右击工程，run as -> run on ?server，访问：http://localhost:8080/biweb/，如下图：
点击按钮，跳转到另一个web：
可以看看日志文件里的内容。