用jsp开发了程序好些时间了，但感觉对jsp的掌握还是不够。现在先分析一下*.jsp文件编译后的*_jsp.java 文件。
先写一个简单的my.jsp文件如下：
<%@ page contenttype="text/html; charset=gb2312" language="java" import="java.sql.*" errorpage="" %>
<!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=gb2312">
<title>baiming</title>
</head>
<body>
hello
</body>
</html>
****************************************************************
把改文件方到 tomcat根目录/webapps/root 下。
运行tomcat，在地址栏里输入http://localhost:8080/my.jsp
在 tomcat根目录/work/catalina/localhost/_/org/apache/jsp 下就会生成my_jsp.java文件。
我们现在来看看这个文件：
package org.apache.jsp;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.sql.*;
public final class my_jsp extends org.apache.jasper.runtime.httpjspbase
implements org.apache.jasper.runtime.jspsourcedependent {
private static java.util.vector _jspx_dependants;
public java.util.list 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;
try {
_jspxfactory = jspfactory.getdefaultfactory();
response.setcontenttype("text/html; charset=gb2312");
pagecontext = _jspxfactory.getpagecontext(this, request, response,
"", true, 8192, true);
application = pagecontext.getservletcontext();
config = pagecontext.getservletconfig();
session = pagecontext.getsession();
out = pagecontext.getout();
_jspx_out = out;
out.write("/r/n");
out.write("<!doctype html public /"-//w3c//dtd html 4.01 transitional//en/" /"http://www.w3.org/tr/html4/loose.dtd/">/r/n");
out.write("<html>/r/n");
out.write("<head>/r/n");
out.write("<meta http-equiv=/"content-type/" content=/"text/html; charset=gb2312/">/r/n");
out.write("<title>baiming</title>/r/n");
out.write("</head>/r/n");
out.write("/r/n");
out.write("<body>/r/n");
out.write("hello/r/n");
out.write("</body>/r/n");
out.write("</html>/r/n");
} catch (throwable t) {
if (!(t instanceof skippageexception)){
out = _jspx_out;
if (out != null && out.getbuffersize() != 0)
out.clearbuffer();
if (pagecontext != null) pagecontext.handlepageexception(t);
}
} finally {
if (_jspxfactory != null) _jspxfactory.releasepagecontext(pagecontext);
}
}
}
你会发现jsp里使用的8个隐含的对象。
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