JSP技术

awt动态 java java动态界面_java

1.jsp脚本和注释

jsp脚本：

1)——>内部的 java 代码翻译到 service 方法内部。

2)——>会被翻译成 service 方法内部 out.print()。

3)  ——>会被翻译成 servlet 的成员内容。

pageEncoding="UTF-8"%>

Insert title here

int i = 0;

System.out.print(i);

%>

效果：

awt动态 java java动态界面_awt动态 java_02

jsp注释：

1)html注释：(可见范围都有 jsp源码 翻译后的 servlet 页面三者)

2)java注释： //单行注释   /*多行注释*/(jsp 源码 翻译后的 servlet)

3)  jsp注释：(jsp源码)

2.jsp运行原理(本质就是 servlet)

jsp 在第一次被访问时会被 Web 容器翻译成 servlet ，在执行过程：

第一次访问——>HelloServlet.java——>HelloServlet_jsp.java

3.jsp 指令(3个)

jsp 的指令是指导 jsp 翻译和运作的命令，jsp 指令包括三大指令：

1)paga 指令

属性最多的一个指令，根据不同的属性，指导整个页面的特性

格式：

常用属性如下：

language : jsp 中嵌入的语言。

pagaEncoding ：当前 jsp 本身的编码——>内部可以包含 contentType

contentType ：文本类型。response.setContextType(text/html;charset = UTF-8);

import : 导包

errorPaga ：配置错误页面

2) include 指令

页面包含指令，可以将一个 jsp 页面包含到另一个 jsp 页面中。

格式 ：

3)taglib 指令

引入标签库。

awt动态 java java动态界面_java web动态生成jsp页面_03

index.jsp
pageEncoding="UTF-8" session = "true" errorPage = "/error.jsp"%>
Insert title here 
 
int i = 0;
System.out.print(i);
List list = new ArrayList();
//int y = 1/0;
%>

翻译后的 java 代码

/*
* Generated by the Jasper component of Apache Tomcat
* Version: Apache Tomcat/7.0.88
* Generated at: 2018-08-02 09:34:07 UTC
* Note: The last modified time of this file was set to
*       the last modified time of the source file after
*       generation to assist with modification tracking.
*/
package org.apache.jsp;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.util.List;
import java.util.ArrayList;
public final class index_jsp extends org.apache.jasper.runtime.HttpJspBase
implements org.apache.jasper.runtime.JspSourceDependent {
String str = "hello world!!!";
private static final javax.servlet.jsp.JspFactory _jspxFactory =
javax.servlet.jsp.JspFactory.getDefaultFactory();
private static java.util.Map _jspx_dependants;
static {
_jspx_dependants = new java.util.HashMap(1);
_jspx_dependants.put("/demo.jsp", Long.valueOf(1533132452526L));
}
private volatile javax.el.ExpressionFactory _el_expressionfactory;
private volatile org.apache.tomcat.InstanceManager _jsp_instancemanager;
public java.util.Map getDependants() {
return _jspx_dependants;
}
public javax.el.ExpressionFactory _jsp_getExpressionFactory() {
if (_el_expressionfactory == null) {
synchronized (this) {
if (_el_expressionfactory == null) {
_el_expressionfactory = _jspxFactory.getJspApplicationContext(getServletConfig().getServletContext()).getExpressionFactory();
}
}
}
return _el_expressionfactory;
}
public org.apache.tomcat.InstanceManager _jsp_getInstanceManager() {
if (_jsp_instancemanager == null) {
synchronized (this) {
if (_jsp_instancemanager == null) {
_jsp_instancemanager = org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(getServletConfig());
}
}
}
return _jsp_instancemanager;
}
public void _jspInit() {
}
public void _jspDestroy() {
}
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,
"/error.jsp", 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(""-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">\r\n");
out.write("\r\n");
out.write("
\r\n"); 
 
out.write("\r\n");
out.write("
Insert title here\r\n"); 
 
out.write("\r\n");
out.write("
\r\n"); 
 
out.write("\t");
out.write("\r\n");
out.write(""-//W3C//DTD HTML 4.01 Transitional//EN\" \"http://www.w3.org/TR/html4/loose.dtd\">\r\n");
out.write("\r\n");
out.write("
\r\n"); 
 
out.write("\r\n");
out.write("
Insert title here\r\n"); 
 
out.write("\r\n");
out.write("
\r\n"); 
 
out.write("\t
\r\n");out.write("\t

This is demo jsp !!!

\r\n"); 
 
out.write("\r\n");
out.write("");
out.write('\r');
out.write('\n');
out.write('    ');
int i = 0;
System.out.print(i);
List list = new ArrayList();
//int y = 1/0;
out.write("\r\n");
out.write("\t\r\n");
out.write("\t");
out.print( i );
out.write('\r');
out.write('\n');
out.write('    ');
out.write('\r');
out.write('\n');
out.write('    ');
out.print( str );
out.write("\r\n");
out.write("\r\n");
out.write("");
} 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);
}
}
}

4.jsp 内置/隐式对象(九个)

名称

类型

描述

out

javax.servlet.jsp.JspWriter

用于页面输出

request

javax.servlet.http.HttpServletRequest

得到用户请求信息

response

javax.sevlet.http.HttpServletResponse

服务器向客户端的回应信息

config

javax.servlet.ServletConfig

服务器配置，可以获取初始化参数

session

javax.servlet.http.HttpSession

用来保存用户的信息

application

javax.servlet.ServletContext

所有用户的共享信息

pageConntext

javax.servlet.jsp.PageContext

JSP 的页面容器

exception

java.lang.Throwable

表示 JSP 页面所发生的异常，在错误页面才起作用

page

java.lang.Object

表示 JSP 页面转换后的 servlet 类的实例

(1)out 对象

out 的类型 ： JspWriter

out 缓冲区默认 8kb 可以设置为 0 写入 response 缓冲区

out.jsp
pageEncoding="UTF-8"%>
Insert title here 
 
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
out.write("bbbbbbbbbbbbbbbbbbbbbbbbbbbbb");
response.getWriter().write("cccccccccccccccccccccccc");
%>

输出结果：

awt动态 java java动态界面_java_04

(2)pageContext 对象

jsp页面上下文对象

作用范围：当前页面

可以获得其他 8 个内置对象！！！

pageContext.getRequest();
pageContext.getResponse();
pageContext.getOut();
pageContext.getSession();
pageContext.getPage();
pageContext.getException();
pageContext.getServletConfig();
pageContext.getServletContext();
pageContext 是一个域对象
pageContext.jsp
pageEncoding="UTF-8"%>
Insert title here 
 
//使用 pageContext 向其他域存信息
pageContext.setAttribute("name", "zhangsan",PageContext.REQUEST_SCOPE);
pageContext.setAttribute("name", "lisi",PageContext.SESSION_SCOPE);
pageContext.setAttribute("name", "wangwu",PageContext.APPLICATION_SCOPE);
%>
pageContext.getRequest();
pageContext.getResponse();
pageContext.getOut();
pageContext.getSession();
pageContext.getPage();
pageContext.getException();
pageContext.getServletConfig();
pageContext.getServletContext();
%>

四大作用域的总结：

page 域(pageContext) ： 当前 jsp 页面。

request 域 ： 一次请求。

session 域  ： 一次会话。

application 域 ： 整个 web 应用。

1.jsp  标签

1)页面包含(动态包含)：

include1.jsp

pageEncoding="UTF-8"%>

Insert title here

This is include1 !!!

include2.jsp效果：

pageEncoding="UTF-8"%>

Insert title here

This is include2 !!!

awt动态 java java动态界面_java_05

2)请求转发(请求转发)：

forward1.jsp

pageEncoding="UTF-8"%>

Insert title here

This is forward1 !!!

forward2.jsp

pageEncoding="UTF-8"%>

Insert title here

This is forward2 !!!

效果：

awt动态 java java动态界面_java_06

静态包含和动态包含的区别？

demo : 商品页面的展示

数据库的部分：

CREATE TABLE `product` (
`pid` VARCHAR(32) NOT NULL,
`pname` VARCHAR(50) DEFAULT NULL,
`market_price` DOUBLE DEFAULT NULL,
`shop_price` DOUBLE DEFAULT NULL,
`pimage` VARCHAR(200) DEFAULT NULL,
`pdate` DATE DEFAULT NULL,
`is_hot` INT(11) DEFAULT NULL,
`pdesc` VARCHAR(255) DEFAULT NULL,
`pflag` INT(11) DEFAULT NULL,
`cid` VARCHAR(32) DEFAULT NULL,
PRIMARY KEY (`pid`)
)

表结构：

awt动态 java java动态界面_java_07

项目结构：

awt动态 java java动态界面_awt动态 java_08

实体类：

package com.ma.domain;
public class Product {
private String pid;
private String pname;
private double market_price;
private double shop_price;
private String pimage;
private String pdate;
private int is_hot;
private String pdesc;
private int pflag;
private String cid;
public String getPid() {
return pid;
}
public void setPid(String pid) {
this.pid = pid;
}
public String getPname() {
return pname;
}
public void setPname(String pname) {
this.pname = pname;
}
public double getMarket_price() {
return market_price;
}
public void setMarket_price(double market_price) {
this.market_price = market_price;
}
public double getShop_price() {
return shop_price;
}
public void setShop_price(double shop_price) {
this.shop_price = shop_price;
}
public String getPimage() {
return pimage;
}
public void setPimage(String pimage) {
this.pimage = pimage;
}
public String getPdate() {
return pdate;
}
public void setPdate(String pdate) {
this.pdate = pdate;
}
public int getIs_hot() {
return is_hot;
}
public void setIs_hot(int is_hot) {
this.is_hot = is_hot;
}
public String getPdesc() {
return pdesc;
}
public void setPdesc(String pdesc) {
this.pdesc = pdesc;
}
public int getPflag() {
return pflag;
}
public void setPflag(int pflag) {
this.pflag = pflag;
}
public String getCid() {
return cid;
}
public void setCid(String cid) {
this.cid = cid;
}
@Override
public String toString() {
return "Product [pid=" + pid + ", pname=" + pname + ", market_price="
+ market_price + ", shop_price=" + shop_price + ", pimage="
+ pimage + ", pdate=" + pdate + ", is_hot=" + is_hot
+ ", pdesc=" + pdesc + ", pflag=" + pflag + ", cid=" + cid
+ "]";
}
}
ProductListServlet
package com.ma.servlet;
import java.io.IOException;
import java.sql.SQLException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
importorg.apache.commons.dbutils.QueryRunner;
importorg.apache.commons.dbutils.handlers.BeanListHandler;
import com.ma.domain.Product;
import com.ma.utils.C3P0Utils;
/**
* Servlet implementation class ProductListServlet
*/
public class ProductListServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//准备好所有数据-----List
QueryRunner runner = new QueryRunner(C3P0Utils.getDataSouce());
String sql = "select * from product";
List productList = null;
try {
productList = runner.query(sql, new BeanListHandler(Product.class));
} catch (SQLException e) {
e.printStackTrace();
}
//商品集合准备好
//将数据存到 request 域转发给 product_list.jsp 显示
request.setAttribute("productList", productList);
request.getRequestDispatcher("/product_list.jsp").forward(request, response);;
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}

工具类：

package com.ma.utils;
import java.sql.Connection;
import java.sql.SQLException;
import javax.management.RuntimeErrorException;
import javax.sql.DataSource;
importcom.mchange.v2.c3p0.ComboPooledDataSource;
public class C3P0Utils {
private static ComboPooledDataSource dataSource = new ComboPooledDataSource();
public static DataSource getDataSouce(){
return dataSource;
}
public static Connection getConnection(){
try {
return dataSource.getConnection();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}

配置文件：

com.mysql.jdbc.Driver

jdbc:mysql:///web17?useUnicode=true&characterEncoding=UTF-8

root

123456

5

20

com.mysql.jdbc.Driver

jdbc:mysql:///web_07

root

123

效果：

awt动态 java java动态界面_java_09