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[Java教程][javaEE] jsp入门


Servlet写java代码很好,但是拼接html的时候,非常不方便

JSP可以在html中嵌套java代码,这样在展示的时候,就会比较方便

 

Tomcat帮我们把jsp的页面翻译成了Servlet去运行的,查看目录

Tomcat目录\work\Catalina\localhost\

生成一个xxx_jsp.java的Servlet文件,jsp的脚本片段放在了_jspService()方法里面

 

使用eclipse创建项目以后,修改一下发布路径,直接发布到Tomcat的webapps目录下,

在Servers标签栏,先删除下面的项目,在右键点open,选择use Tomcat installation

 

jsp声明:<%! 若干java代码%>,此处的代码会解析到类的成员的地方

jsp注释:<%--注释的内容--%>

index.jsp

<%@page import="org.apache.jasper.tagplugins.jstl.core.Out"%><%@page import="java.util.Date"%><%@ page language="java" contentType="text/html; charset=utf-8"  pageEncoding="utf-8"%><!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=utf-8"><title>首页</title></head><body><%!public void test(){  int a=0;}%><% for(int i=0;i<5;i++){  out.write(i+"");}%><%-- Date date=new Date();out.write(date.toLocaleString());--%>你好,JSP</body></html>

index_jsp.java

public final class index_jsp extends org.apache.jasper.runtime.HttpJspBase  implements org.apache.jasper.runtime.JspSourceDependent {public void test(){  int a=0;} public void _jspService(final javax.servlet.http.HttpServletRequest request, final javax.servlet.http.HttpServletResponse response)    throws java.io.IOException, javax.servlet.ServletException {  final javax.servlet.jsp.PageContext pageContext;  javax.servlet.http.HttpSession session = null;  final javax.servlet.ServletContext application;  final javax.servlet.ServletConfig config;  javax.servlet.jsp.JspWriter out = null;  final java.lang.Object page = this;  javax.servlet.jsp.JspWriter _jspx_out = null;  javax.servlet.jsp.PageContext _jspx_page_context = null;  try {   response.setContentType("text/html; charset=utf-8");   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("\r\n");   out.write("\r\n");   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=utf-8\">\r\n");   out.write("<title>首页</title>\r\n");   out.write("</head>\r\n");   out.write("<body>\r\n");   out.write('\r');   out.write('\n'); for(int i=0;i<5;i++){  out.write(i+"");}   out.write('\r');   out.write('\n');   out.write("\r\n");   out.write("你好,JSP\r\n");   out.write("</body>\r\n");   out.write("</html>");  } catch (java.lang.Throwable t) {   if (!(t instanceof javax.servlet.jsp.SkipPageException)){    out = _jspx_out;    if (out != null && out.getBufferSize() != 0)     try {      if (response.isCommitted()) {       out.flush();      } else {       out.clearBuffer();      }     } catch (java.io.IOException e) {}    if (_jspx_page_context != null) _jspx_page_context.handlePageException(t);    else throw new ServletException(t);   }  } finally {   _jspxFactory.releasePageContext(_jspx_page_context);  } }