servlet /jsp

html(doPost/doGet)--->servlet(导航逻辑)--->bean(表示逻辑)--->业务类--->数据库；  
  数据库--->业务类--->bean(表示逻辑)--->servlet(导航逻辑)--->jsp.

jsp,一种页面技术,
javabean,一种可以利用反射的技术
servlet,一种接收处理请求的技术

jsp在运行的时候是先编译成servlet再执行的，servlet根javabean都是先要编译成class字节码文件才能执行的。jsp是将 script根html混合在一起的，适合做小型的或者扩展要求不高的系统，大一点的要求有扩展性的系统可以将javabean结合起来，将一些常用的功 能封装在里面，可以节省劳力，而且将来扩展相对容易，再大一些的系统就需要将servlet结合起来用了，servlet侧重在流程控制，jsp里面由于 可以直接用html，故侧重表示，javabean就侧重封装逻辑功能，比如数据库访问等。

 

executeQuery的返回值是一个数据的结果集 ResultSet
executeUpdate的返回值是成功更新数据的行数
1.当要执行的sql语句为select语句，则应该用executeQuery
2.当要执行的sql语句是insert，update，delete和dll语句，则应该用executeUpdate

 

//跳转到servlet

response.sendRedirect("list");  //http://localhost:8080/Shop/admin/list

//跳转到jsp

response.sendRedirect("test.jsp");  //http://localhost:8080/Shop/admin/list

 

//转发

request.setAttribute("pagediv", pagediv);
RequestDispatcher dispatcher=request.getRequestDispatcher("goodsList.jsp");
dispatcher.forward(request, response);

 

 

 

 

--------------------------------------------JDBC实例 Statement,PreparedStatement,CallableStatement三个方法的实例

 

  Statement  
              |  
  PreparedStatement  
              |  
  CallableStatement  
   
  Statement用于执行一条普通的动态SQL语句，PreparedStatement用于执行预编译好的SQL语句，CallableStatement用于调用数据库的存储过程。他们的继承关系如上。

 

----  1 Statement

            stmt = conn.createStatement();    
            rs = stmt.executeQuery("select * from goods LIMIT "+fpage+" , "+pageSize+" ");    
            while(rs.next()){
                Good good = new Good(rs.getString("id"),rs.getString("nnn"));
                result.add(good);
            }

 

 

 

            stmt = conn.createStatement();
            stmt.executeUpdate("delete from goods where id="+id);

 

 

----  2 CallableStatement

            pstm=con.prepareStatement("select * from Goods where GoodsID=?");
            pstm.setString(1, goodsID);
            rs=pstm.executeQuery();
            while(rs.next()){
                Goods goods=new Goods(rs.getString("goodsID"),rs.getString("goodsName"));
                destroy();
                return goods;
            }

 

            pstm=con.prepareStatement("delete from ShoppingCarDetails where carID=? and goodsID=?");
            pstm.setString(1, carID);
            pstm.setString(2, goodsID);
            pstm.executeUpdate();

 

----  3 PreparedStatement

            csmt=con.prepareCall("{call getAllCustomer()}");
            rs=csmt.executeQuery();
            while (rs.next()) {
                Customer customer=new Customer(rs.getInt("customerID"),rs.getString("customerName"),rs.getString("customerPassword"),rs.getString("customerAddress"));
                result.add(customer);
            }

 

 

 

 

 

-------------------------建立静态方法类，可当函数一样直接调用，不用实例化对象

 

package soyo.shopping.lib;

/*
 * customerName=ChangeEncoding.changeToGBK(customerName);
 */
public class ChangEncoding {
    public static String changeToGBK(String value){
        String result = "";
        try {
            if (value != null&&!value.equals("")) {
                result = new String(value.getBytes("ISO-8859-1"), "GB2312");
            }
        } catch (Exception e) {
            System.err.println("ChangeEncoding.changeToGBK Error ## "
                    + e.getMessage());
        }
        return result;
    }
}

 

 

 

 

----------------------------------------  session

 

            if(customer!=null){  //成功插入记录
            page="success.jsp";
            HttpSession session=request.getSession();
            session.setAttribute("customer", customer);  //把用户添加到会话
            request.setAttribute("message", "注册成功！欢迎您 "+customerName);
        }
        else {
            request.setAttribute("message", "注册失败，请重新注册");
        }
        RequestDispatcher dispatcher=request.getRequestDispatcher(page);
        dispatcher.forward(request, response);



            HttpSession session=request.getSession();
            Customer customer=(Customer)session.getAttribute("customer");
            CustomerServices customerServices=new CustomerServices();
            boolean result;
            result=customerServices.buyGoods(customer.getCustomerID(), goodsID, 1);

 

 

 

 

-------------------------------------------Servlet中doGet()，doPost()，service()函数的关系

 

1，三者之间的关系：doGet()和doPost()是由函数service()调用才执行的。也就是说，当从HttpServlet类继承时可 以绕过doGet()和doPost()直接override service()函数，也可以override doGet()和doPost()

2，service() 该函数使用起来不像duPost()与duGet()那样有约束，但几乎失去了HttpServlet的意义。很类似于GeneratServlet

3，doGet() 超链接或直接在浏览器地址栏访问时起作用

4，doPost() form提交时起作用

如果两者均有，则可用service() 或者

protected void doGet(HttpServletRequest rst, HttpServletResponse resp) throws ServletException , java.io.IOException {

    doPost(req,resp);

}

 

 

 

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class GoodListServlet extends HttpServlet {

    public GoodListServlet() {
        super();
    
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            response.setContentType("text/html;charset=GBK");
            String id=request.getParameter("id");

    }

}

 

 

---------------------------------------- java.util.List   ,LinkedList和ArrayList

 

java.util.List   是个接口，LinkedList和ArrayList是实现了List这个接口的类。

LinkedList和ArrayList   分别是list最常用的两个子类， 
  LinkedList善于频繁的增，删操作 
  ArrayList   善于快速查找  


import java.util.LinkedList;
import java.util.List;


List<Good> result=new LinkedList<Good>();
while(rs.next()){
                Good good = new Good(rs.getString("id"),rs.getString("nnn"));
                result.add(good);
            }



import java.util.ArrayList;
　　ArrayList arrayList = new ArrayList();


-----linkedList 应用实例
servlet:
List<Good> result=goodServices.getRecordAll();

goodServices.java
public List<Good> getRecordAll(){
        List<Good> result=goodDAO.getRecordAll();
        return result;
    }

goodDAO.java
    public List<Good> getRecordAll(){
        List<Good> result=new LinkedList<Good>();
        try {
            stmt = conn.createStatement();    
            rs = stmt.executeQuery("select * from goods");    
            while(rs.next()){
                Good good = new Good(rs.getString("id"),rs.getString("nnn"));
                result.add(good);
            }
            destroy();
        } catch (Exception e) {
            System.err.println("PaginationDAO.getRecordNumber ERROR ## "+e.getMessage());
        }
        return result;
    }

 

 

 

-----------------------------------建立自己的bean

TestBean.java

package test;
public class TestBean{
　private String name = null;
　public TestBean(String strName_p){
　　　this.name=strName_p;
　　}
　　public void setName(String strName_p){
　　　this.name=strName_p;
　　}
　　public String getName(){
　　　return this.name;
　}
}

 

 

jsp页面

<%@ page import="test.TestBean" %>
<%
TestBean testBean=new TestBean("This is a test java bean.");
%>
Java bean name is: <%=testBean.getName()%>

 

 

 

 

 

------------------------------------手动编译 第一个servlet

 

HelloWorld.java

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloWorld extends HttpServlet
{
    public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException
    {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<html><head><title>");
        out.println("This is my first Servlet");
        out.println("</title></head><body>");
        out.println("<h1>Hello,World!</h1>");
    out.println("</body></html>");

}
}

用javac HelloWorld.java来编译这个文件，如果出现无法import javax.servlet.*
那么就是应该把C:\Tomcat\common\lib里面的servlet.jar文件拷贝到C:\JDK\jre\lib\ext中，再次编译，就没有问题了！

 

然后在Tomcat目录里面的C:\Tomcat\webapps\ROOT里面按如下的文件结构：
ROOT\index.html
ROOT\welcom.jsp
ROOT\WEB-INF\lib\MyServlet.jar（如果你的servlet的.class打成了.jar文件，则放在
lib下面)
ROOT\WEB-INF\classes\HelloWorld.class(把上面生成的HelloWorld.class文件放在这个
里面)
然后在浏览器中输入http://localhost:8080/servlet/HelloWorld,于是Server众望所归的报错了:Error 404--Not Found
怎么回事呢？
Servlet必须使用C:\Tomcat\webapps\ROOT\WEB-INF这个目录下面的web.xml文件进行注册，
用EP打开这个web.xml文件，

把下面这段程序

    <servlet>
        <servlet-name>org.apache.jsp.index_jsp</servlet-name>
        <servlet-class>org.apache.jsp.index_jsp</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>org.apache.jsp.index_jsp</servlet-name>
        <url-pattern>/index.jsp</url-pattern>
</servlet-mapping>
替换成
<servlet>
<servlet-name>HelloWorld</servlet-name>
<servlet-class>HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>/servlet/HelloWorld</url-pattern>
</servlet-mapping>
如果没有的话，就直接加那段代码

为什么呢？
因为 这样的结构
<servlet>
<servlet-name>HelloWorld</servlet-name>
<servlet-class>HelloWorld</servlet-class>
</servlet>
表示指定包含的servlet类.
而以下的结构
<servlet-mapping>
<servlet-name>HelloWorld</servlet-name>
<url-pattern>/servlet/HelloWorld</url-pattern>
</servlet-mapping>
表示指定HelloServlet应当映射到哪一种URL模式。
在修改web.xml完毕过后，重新启动Server，然后再输入http://localhost:8080/servlet/HelloWorld，那么偌大一个Hello,World!等

 

 

 

 

 

------------------------------------eclipse 第一个servlet 【附实例下载1.rar】

 

 

新建web-Dynamic Web Project   项目名为Test

eclipse：WebContent/web.xml

    <servlet>
        <servlet-name>HelloWorld</servlet-name>
        <servlet-class>HelloWorld</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HelloWorld</servlet-name>
        <url-pattern>/servlet/HelloWorld </url-pattern>
    </servlet-mapping>


在eclipse  src下创建HelloWorld.java
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class HelloWorld extends HttpServlet
{
    public void doGet(HttpServletRequest

request,HttpServletResponse response)throws

ServletException,IOException
    {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<html><head><title>");
        out.println("This is my first Servlet");
        out.println("</title></head><body>");
        out.println("<h1>Hello,World!</h1>");
    out.println("</body></html>");

    }
}


再将servlet-api.jar拷贝到eclipse  WebConent/lib下


关闭tomcat，导出Test项目到webapp下，开启tomcat访问
http://localhost:81/Test/servlet/HelloWorld

 

 

 

 

------------------------------------  连接mysql

 

－－－－－－－－JSP实例

<%@page language="java" %>
<%@page import="com.mysql.jdbc.*" %>
<%@page import="java.sql.*" %>

<%
String driverName="com.mysql.jdbc.Driver";
String username="root";
String psw="****";
String dbName="test";
String tableName="user";

String url="jdbc:mysql://localhost/"+dbName+"?user="+username+"&password="+psw;
try
{
    Class.forName("com.mysql.jdbc.Driver").newInstance();
    java.sql.Connection conn=DriverManager.getConnection(url);
    out.print("ok");
   
    java.sql.Statement statement = conn.createStatement();
    String sql = "select * from "+tableName;
    java.sql.ResultSet rs= statement.executeQuery(sql);
    while(rs.next())
    {
        out.print(rs.getString(1)+"-");//rs.getInt("AdminID");
       
        out.print(rs.getString(2)+"-");
       
        out.print(rs.getString(3));
       
        out.print("<br>");
    }
   
    rs.close();
    statement.close();
    conn.close();
}
catch(SQLException ex)
{
    out.print("error");
}
 %>

 

----------------------------------------------------------------【附完整eclipse项目实例下载Shop.rar】servlet 连接mysql

 

 

 

 

共6个文件 ，目录结构如下：

 

 

 

 

1 web.xml 文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <display-name>Shop</display-name>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    <servlet>
        <description></description>
        <display-name>GoodListServlet</display-name>
        <servlet-name>GoodListServlet</servlet-name>
        <servlet-class>soyo.shopping.servlet.admin.GoodListServlet </servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GoodListServlet</servlet-name>
        <url-pattern>/admin/list </url-pattern>
    </servlet-mapping>
</web-app>

 

 

 

2 GoodListServlet.java

 

package soyo.shopping.servlet.admin;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import soyo.shopping.services.*;

public class GoodListServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    int result;
    /**
     * @see HttpServlet#HttpServlet()
     */
    public GoodListServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       
        GoodServices goodServices=new GoodServices();
        result = goodServices.getRecordNumber();
        response.setHeader("Pragma","No-cache"); 
        response.setDateHeader("Expires",0); 
        response.setHeader("Cache-Control","no-cache"); 
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        out.println("<h1>Hello,World!</h1>");
        out.println(result);
        out.println("<h1>Hello,World2!</h1>");
    }

}

 

 

 

 

 

3 GoodServices.java

 

package soyo.shopping.services;

import soyo.shopping.dao.GoodDAO;
import soyo.shopping.entity.Good;

public class GoodServices {
    GoodDAO goodDAO;
   
    public GoodServices() {
        goodDAO=new GoodDAO();
    }
   
    public int getRecordNumber(){
        return goodDAO.getRecordNumber();
    }
   
}

 

 

4 Good.java

 

package soyo.shopping.entity;

public class Good {
    private String nnn;
   
    public Good(){
           
    }
   
    public Good(String nnn)
    {
        setGoodsNNN(nnn);
    }
   
    public String getGoodsNNN() {
        return nnn;
    }
    public void setGoodsNNN(String nnn) {
        this.nnn = nnn;
    }
}

 

 

 

5 GoodDAO.java

 

package soyo.shopping.dao;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.LinkedList;
import java.util.List;

public class GoodDAO {
    Connection conn;
    public GoodDAO(){
        Init init=new Init();
        conn=init.connent();
    }
   
    public int getRecordNumber(){
        int count=0;
        try {
            Statement stmt = conn.createStatement();    
            ResultSet rs = stmt.executeQuery("select count(*) from goods");    
            System.out.println("PaginationDAO.getRecordNumber 12");
            while(rs.next()){
                count=rs.getInt(1);
                break;
            }
            //destroy();
        } catch (Exception e) {
            System.err.println("PaginationDAO.getRecordNumber ERROR ## "+e.getMessage());
        }
        return count;
    }
}

 

6 Init.java

 

package soyo.shopping.dao;

import java.sql.Connection;
import java.sql.DriverManager;

public class Init {
    private Connection conn;
    public Init(){
        conn=null;
    }
    public  Connection connent(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/shoppingDB", "root", "123456");
        } catch (Exception e) {
            System.out.println("DAO.init ERROR ## "+e.getMessage());
        }
        return conn;
    }
}

 

 

 

 

 

 

----------------------------------------------------------------【附完整eclipse项目实例下载Shop2.rar】servlet 连接mysql，然后转发到JSP 页面 jstl显示

 

提问参考地址：http://www.iteye.com/problems/25219

 

list 类起到了关键作用

 

结构图如上图

 

 

--------1 web.xm

 

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <display-name>Shop</display-name>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
    <servlet>
        <description></description>
        <display-name>GoodListServlet</display-name>
        <servlet-name>GoodListServlet</servlet-name>
        <servlet-class>soyo.shopping.servlet.admin.GoodListServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>GoodListServlet</servlet-name>
        <url-pattern>/admin/list</url-pattern>
    </servlet-mapping>
</web-app>

 

 

---------2 GoodListServlet.java

 

 

package soyo.shopping.servlet.admin;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import soyo.shopping.services.*;
import soyo.shopping.entity.Good;

public class GoodListServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    int numbers;
    /**
     * @see HttpServlet#HttpServlet()
     */
    public GoodListServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
       
        GoodServices goodServices=new GoodServices();
        List<Good> result=goodServices.getRecordAll();
        numbers = goodServices.getRecordNumber();
       
        //1 直接输出
//        if(result.size()>0){
//        PrintWriter out = response.getWriter();
//        out.println(result.size());
//        for(int i=0;i<result.size();i++){
//              out.println(result.get(i));
//        }
//
//    }
       

        //2 转发
        request.setAttribute("goodsList", result);
        request.setAttribute("numbers", numbers);
        RequestDispatcher dispatcher=request.getRequestDispatcher("goodsList.jsp");
        dispatcher.forward(request, response);
    }

}

 

---------------------3 GoodServices

 

package soyo.shopping.services;

import java.util.List;
import soyo.shopping.dao.GoodDAO;
import soyo.shopping.entity.Good;

public class GoodServices {
    GoodDAO goodDAO;
   
    public GoodServices() {
        goodDAO=new GoodDAO();
    }
   
    public int getRecordNumber(){
        return goodDAO.getRecordNumber();
    }
    public List<Good> getRecordAll(){
        List<Good> result=goodDAO.getRecordAll();
        return result;
    }
   
}

 

 

----------------------------4 GoodDAO

package soyo.shopping.dao;

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.LinkedList;
import java.util.List;

import soyo.shopping.entity.Good;




public class GoodDAO {
    Connection conn;
    public GoodDAO(){
        Init init=new Init();
        conn=init.connent();
    }
   
    public int getRecordNumber(){
        int count=0;
        try {
            Statement stmt = conn.createStatement();    
            ResultSet rs = stmt.executeQuery("select count(*) from goods");    
            System.out.println("PaginationDAO.getRecordNumber 12");
            while(rs.next()){
                count=rs.getInt(1);
                break;
            }
            //destroy();
        } catch (Exception e) {
            System.err.println("PaginationDAO.getRecordNumber ERROR ## "+e.getMessage());
        }
        return count;
    }
   
    public List<Good> getRecordAll(){
        List<Good> result=new LinkedList<Good>();
        try {
            Statement stmt = conn.createStatement();    
            ResultSet rs = stmt.executeQuery("select * from goods");    
            while(rs.next()){
                Good good = new Good(rs.getString("nnn"));
                result.add(good);
            }
            //destroy();
        } catch (Exception e) {
            System.err.println("PaginationDAO.getRecordNumber ERROR ## "+e.getMessage());
        }
        return result;
    }
   
}

-----------------------5 Init

package soyo.shopping.dao;

import java.sql.Connection;
import java.sql.DriverManager;

public class Init {
    private Connection conn;
    public Init(){
        conn=null;
    }
    public  Connection connent(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
            conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/shoppingDB", "root", "123456");
        } catch (Exception e) {
            System.out.println("DAO.init ERROR ## "+e.getMessage());
        }
        return conn;
    }
}

------------------6 goodlist.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
page Size : ${numbers}
<c:forEach items="${goodsList}" var="good">
${good.nnn}
</c:forEach>

 

 

 

 

----------jsp显示

<%       

<%@ page language="java" import="java.util.*,java.sql.*,soyo.shopping.*,java.io.*,javax.*" pageEncoding="GBK"%>
List rss=(List)request.getAttribute("goodsList");
int numbers=(Integer)request.getAttribute("numbers");
%> 
<%=numbers %>

 

 

 

 

 

 

 

-------------------------------------------增加分页功能 shop3.rar

 

 

 

 

-------------------------------------------增加分页功能,增加修改删除 shop4.rar