用servlet和jsp做探索数据库

1.建一个web文件，在里面分三层，分别是实体层；DAO层，DAO层里面包含BaseDAO（数据访问层）和DAO层；还有一个servlet层，处理数据逻辑层！

一、实体层，建立两个实体，一个members，和一个product：

 package com.chinasoft.jsptest.entity;

 public class Menbers {
     private int id;
     private String name;
     private String pwd;
     private String email;
     private String born;
     private String sex;

     public Menbers() {
         super();
         // TODO Auto-generated constructor stub
     }

     public Menbers(String name, String pwd, String email, String born,
             String sex) {
         super();
         this.name = name;
         this.pwd = pwd;
         this.email = email;
         this.born = born;
         this.sex = sex;
     }

     public String getEmail() {
         return email;
     }

     public void setEmail(String email) {
         this.email = email;
     }

     public String getBorn() {
         return born;
     }

     public void setBorn(String born) {
         this.born = born;
     }

     public String getSex() {
         return sex;
     }

     public void setSex(String sex) {
         this.sex = sex;
     }

     public int getId() {
         return id;
     }

     public void setId(int id) {
         this.id = id;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public String getPwd() {
         return pwd;
     }

     public void setPwd(String pwd) {
         this.pwd = pwd;
     }
 }

 package com.chinasoft.jsptest.entity;

 public class Product {
     public int id ;
     public String name  ;
     public String money ;
     public int getId() {
         return id;
     }
     public void setId(int id) {
         this.id = id;
     }
     public String getName() {
         return name;
     }
     public void setName(String name) {
         this.name = name;
     }
     public String getMoney() {
         return money;
     }
     public void setMoney(String money) {
         this.money = money;
     }

 }

二、DAO层

1.BaseDAO

 package com.chinasofti.jsptest.dao;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;

 public class BaseDAO {
    //1.链接数据库
     String className="com.microsoft.sqlserver.jdbc.SQLServerDriver";
     String connectionString="jdbc:sqlserver://127.0.0.1;DatabaseName=JspTest";
     String username="sa";
     String userpwd="123456";

     private Connection conn;
     private PreparedStatement pst;
     private ResultSet rst;

   //2. 链接上表
     public BaseDAO(){
         try {
             Class.forName(className);
         } catch (ClassNotFoundException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }
     public void getconnection(){
         try {
             conn=DriverManager.getConnection(connectionString,username,userpwd);
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }

     public ResultSet ExecuteQuest(String sql){
         getconnection();
         return ExecuteQuest(sql,new Object[]{});
     }
      public ResultSet ExecuteQuest(String sql, Object[] params) {
          getconnection();
           try {
             pst=conn.prepareStatement(sql);
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
          for(int i=0;i<params.length;i++){
              try {

                 pst.setObject(i+1, params[i]);
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
          }
          try {
             rst=pst.executeQuery();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
          return rst;
     }

     public int ExecuteUpdate(String sql){
         getconnection();
         return ExecuteUpdate(sql,new Object[]{});
       }
       public int ExecuteUpdate(String sql,Object[] params){
         getconnection();
         int result=0;
         try {
             pst=conn.prepareStatement(sql);
         } catch (SQLException e) {
             e.printStackTrace();
         }
         for(int i=0;i<params.length;i++){
             try {
                 pst.setObject(i+1, params[i]);
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
         try {
             result=pst.executeUpdate();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         return result;
       }

     public void CloseAll(){
             try{
                 if(!rst.isClosed()){
                     rst.close();
                 }
                 if(!pst.isClosed()){
                     pst.close();
                 }
                 if(!conn.isClosed()){
                     conn.close();
                 }
             }catch(Exception e){
                 System.out.println(e.getMessage());
             }
         }

 }

2.DAO

 package com.chinasofti.jsptest.dao;

 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 import com.chinasoft.jsptest.entity.Menbers;

 public class MenbersDAO {
     //1.new一个
    private BaseDAO dao = new BaseDAO();
    //2.增加ExecuteUpdate;
    public void Add(Menbers meb){
       String  sql = "insert into [test]([id],[name],[pwd],[email],[born],[sex]) values (?,?,?,?,?,?)";
       Object[] params=new Object[]{meb.getId(),meb.getName(),meb.getPwd(),meb.getEmail(),meb.getBorn(),meb.getSex()};
       dao.ExecuteUpdate(sql,params);
    }
    //3.删除ExecuteUpdate;
    public void Delete(Menbers meb){
        String sql = "delete from [test] where [id]=?";
        Object[] params = new Object[]{meb.getId()};
        dao.ExecuteUpdate(sql,params);
    }
    //4.修改ExecuteUpdate;
    public void Update(Menbers meb){
        String sql="update [tset] set [name]=?,[pwd]=? WHERE [id]=?";
         Object [] params=new Object[]{meb.getName(),meb.getPwd(),meb.getId()};
         dao.ExecuteUpdate(sql,params);
    }
    //5.查找全部ExecuteQuest;
    public List<Menbers> getselect(){
        List<Menbers> result=new ArrayList<Menbers>();
        String sql="SELECT [id],[name],[pwd] ,[email],[sex]FROM [test]";
        ResultSet rst=dao.ExecuteQuest(sql);
        try{
         while(rst.next()){
                 Menbers temp=new Menbers();
                 temp.setId(rst.getInt(1));
                 temp.setName(rst.getString(2));
                 temp.setPwd(rst.getString(3));
                 temp.setEmail(rst.getString(4));
                 temp.setSex(rst.getString(5));
                 result.add(temp);
             }
     } catch (SQLException e) {
         // TODO Auto-generated catch block
         e.printStackTrace();
     }
        dao.CloseAll();
        return result;
    }
    //6.按照ID查找ExecuteQuest;
      public Menbers getSelectid(int id){
          Menbers result=null;
          String sql="SELECT [id],[name],[pwd] FROM [test] WHERE [id]=?";
          Object[] params=new Object[]{id};
          ResultSet rst=dao.ExecuteQuest(sql,params);
          try {
              if(rst.next()){
                  result = new Menbers();
                  result.setId(rst.getInt(1));
                  result.setName(rst.getString(2));
                  result.setPwd(rst.getString(3));
              }
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }
          dao.CloseAll();
          return result;
      }
    //7.按照name查找ExecuteQuest;
      public Menbers getSelectname(String name){
          Menbers result=null;
          String sql="SELECT [id],[name],[pwd] FROM [test] WHERE [name]=?";
          Object[] params=new Object[]{name};
          ResultSet rst=dao.ExecuteQuest(sql,params);
          try {
              if(rst.next()){
                  result = new Menbers();
                  result.setId(rst.getInt(1));
                  result.setName(rst.getString(2));
                  result.setPwd(rst.getString(3));
              }
          } catch (SQLException e) {
              // TODO Auto-generated catch block
              e.printStackTrace();
          }
          dao.CloseAll();
          return result;
      }

 }

MembersDAO

 package com.chinasofti.jsptest.dao;

 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;

 import com.chinasoft.jsptest.entity.Product;

 public class ProductDAO {
         private  BaseDAO dao = new BaseDAO();
         //1.增加
         public void Add(Product put){
             String sql ="insert into [Product]([name],[money]) values(?,?)";
             Object[] params = new Object[]{put.getName(),put.getMoney()};
             dao.ExecuteUpdate(sql, params);
         }
     //2.删除
         public void delete(int id){
             String sql ="delete [Product] where [id]=?";
             Object[] params = new Object[]{id};
             dao.ExecuteUpdate(sql, params);
         }
        //3.更改
         public void Update (Product put){
             String sql ="update [Product] set [name]=?,[money]=? where [id]=?";
             Object[] params = new Object[]{put.getName(),put.getMoney(),put.getId()};
             dao.ExecuteUpdate(sql, params);
         }
       //4.查找全部
         public List <Product > getSelect(){
             List <Product> result=new ArrayList<Product>();
             String sql ="select [id] ,[name],[money] from [Product]  ";
             ResultSet rst = dao.ExecuteQuest(sql);
             try {
                 while (rst.next()){
                     Product pro = new Product();
                      pro.setId(rst.getInt(1));
                      pro.setName(rst.getString(2));
                      pro.setMoney(rst.getString(3));
                     result.add(pro);
                 }
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
             dao.CloseAll();
             return result;
         }
         //5.根据name查找
         public Product getname(String name){
             Product pro = null;
             Object [] params = new Object[]{name};
             String sql ="select [name],[money],[id] from [Product] where[name]=? ";
             ResultSet rst = dao.ExecuteQuest(sql,params);
             try {
                 while (rst.next()){
                     pro = new Product();
                      pro.setId(rst.getInt(1));
                      pro.setName(rst.getString(2));
                      pro.setMoney(rst.getString(3));
                 }
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
             dao.CloseAll();
             return pro;

         } 

 }

ProductDAO

三、servlet层 需要建servlet类,里面会直接生成servlet/xxxx地址。这样在访问的时候，就直接访问这个地址

1.登录注册的逻辑判断层，主要注意request的用法；还有就是跳转jsp以后，jsp用post方法提交到的action地址，是servlet映射的地址！这个在WebRoot-web-inf-web.hml可以找到

 package com.chinasofti.jsptest.servlet;

 import java.io.IOException;

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

 import com.chinasoft.jsptest.entity.Menbers;
 import com.chinasofti.jsptest.dao.MenbersDAO;

 @SuppressWarnings("serial")
 public class goset extends HttpServlet {

     /**
      * Constructor of the object.
      */
     public goset() {
         super();
     }

     /**

      */
     public void destroy() {
         super.destroy(); // Just puts "destroy" string in log
         // Put your code here
     }

     /**
      *
      *
      * This method is called when a form has its tag value method equals to get.
      *
      * @param request
      *            the request send by the client to the server
      * @param response
      *            the response send by the server to the client
      * @throws ServletException
      *             if an error occurred
      * @throws IOException
      *             if an error occurred
      */
     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         request.getRequestDispatcher("../go30-1.jsp").forward(request, response);//指向你要过去的JSP，进行逻辑判断以后，以post方法，进行下面的逻辑判断
     }

     /**
      *
      *
      * This method is called when a form has its tag value method equals to
      * post.
      *
      * @param request
      *            the request send by the client to the server
      * @param response
      *            the response send by the server to the client
      * @throws ServletException
      *             if an error occurred
      * @throws IOException
      *             if an error occurred
      */
     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         request.setCharacterEncoding("utf-8");
         String name = request.getParameter("name");
         String pwd = request.getParameter("pwd");
         String emai = request.getParameter("email");
         String born = request.getParameter("born");
         String sex = request.getParameter("sex");
         String type = request.getParameter("type");
         if ("login".equals(type)) {
             MenbersDAO dao = new MenbersDAO();
             Menbers m = dao.getSelectname(name);
             if (m != null && m.getPwd().equals(pwd)) {
                 request.setAttribute("title", "登陆成功");
                 request.setAttribute("retn", "欢迎你," + name + "。");
                 request.getRequestDispatcher("../go30-2.jsp").forward(request,
                         response);//指向你要过去的JSP
             } else if (m != null && !m.getPwd().endsWith(pwd)) {
                 request.setAttribute("title", "登陆失败");
                 request.setAttribute("retn", "用户名或密码错误！请重新登录 ");
                 request.getRequestDispatcher("../go30-3.jsp").forward(request,
                         response);//指向你要过去的JSP
             } else {
                 request.setAttribute("retn", "你不是公司员工，请入职以后再登入");
                 request.getRequestDispatcher("../go30-4.jsp").forward(request,
                         response);//指向你要过去的JSP
             }
         } else if ("register".equals(type)) {
             Menbers m = new Menbers(name, pwd, emai, born, sex);
             MenbersDAO dao = new MenbersDAO();
             dao.Add(m);
             request.getRequestDispatcher("../go30-4.jsp").forward(request,
                     response);//指向你要过去的JSP
         }

     }

     /**
      *
      * @throws ServletException
      *             if an error occurs
      */
     public void init() throws ServletException {
         // Put your code here
     }

 }

goset.java

2.显示全部界面，只用看get方法就好了

 package com.chinasofti.jsptest.servlet;

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

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

 import com.chinasoft.jsptest.entity.Product;
 import com.chinasofti.jsptest.dao.ProductDAO;

 public class ProductSevlet extends HttpServlet {

     /**
      * Constructor of the object.
      */
     public ProductSevlet() {
         super();
     }

     public void destroy() {
         super.destroy(); // Just puts "destroy" string in log
         // Put your code here
     }

     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
             ProductDAO dao = new ProductDAO();
             List<Product> ms= dao.getSelect();
             request.setAttribute("Model", ms);
             request.getRequestDispatcher("../Product.jsp").forward(request, response);

     }

     /**
      * The doPost method of the servlet. <br>
      *
      * This method is called when a form has its tag value method equals to post.
      *
      * @param request the request send by the client to the server
      * @param response the response send by the server to the client
      * @throws ServletException if an error occurred
      * @throws IOException if an error occurred
      */
     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {

         response.setContentType("text/html");
         PrintWriter out = response.getWriter();
         out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
         out.println("<HTML>");
         out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
         out.println("  <BODY>");
         out.print("    This is ");
         out.print(this.getClass());
         out.println(", using the POST method");
         out.println("  </BODY>");
         out.println("</HTML>");
         out.flush();
         out.close();
     }

     /**
      * Initialization of the servlet. <br>
      *
      * @throws ServletException if an error occurs
      */
     public void init() throws ServletException {
         // Put your code here
     }

 }

ProducAction.java

 package com.chinasofti.jsptest.servlet;

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

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

 import com.chinasoft.jsptest.entity.Menbers;
 import com.chinasofti.jsptest.dao.MenbersDAO;

 public class UserList extends HttpServlet {

     /**
      * Constructor of the object.
      */
     public UserList() {
         super();
     }

     /**
      * Destruction of the servlet. <br>
      */
     public void destroy() {
         super.destroy(); // Just puts "destroy" string in log
         // Put your code here
     }

     /**
      * The doGet method of the servlet. <br>
      *
      * This method is called when a form has its tag value method equals to get.
      *
      * @param request the request send by the client to the server
      * @param response the response send by the server to the client
      * @throws ServletException if an error occurred
      * @throws IOException if an error occurred
      */
     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {

         MenbersDAO dao= new MenbersDAO();
         List <Menbers> ms = dao.getselect();
         request.setAttribute("Model", ms);
         request.getRequestDispatcher("../UserList.jsp").forward(request, response);
     }

     /**
      * The doPost method of the servlet. <br>
      *
      * This method is called when a form has its tag value method equals to post.
      *
      * @param request the request send by the client to the server
      * @param response the response send by the server to the client
      * @throws ServletException if an error occurred
      * @throws IOException if an error occurred
      */
     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {

         response.setContentType("text/html");
         PrintWriter out = response.getWriter();
         out.println("<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.01 Transitional//EN\">");
         out.println("<HTML>");
         out.println("  <HEAD><TITLE>A Servlet</TITLE></HEAD>");
         out.println("  <BODY>");
         out.print("    This is ");
         out.print(this.getClass());
         out.println(", using the POST method");
         out.println("  </BODY>");
         out.println("</HTML>");
         out.flush();
         out.close();
     }

     /**
      * Initialization of the servlet. <br>
      *
      * @throws ServletException if an error occurs
      */
     public void init() throws ServletException {
         // Put your code here
     }

 }

UserList.java

jsp界面，所有的显示界面

 <form method="post" action="<%=request.getContextPath() %>/servlet/goset">
         <input type="hidden" name="type" value="login">
         <table border="0" align="center">
             <tr>
                 <td>用户名</td>
                 <td><input type="text" name="name"></td>
             </tr>
             <tr>
                 <td>密码</td>
                 <td><input type="password" name="pwd"></td>
             </tr>

             <tr>
                 <td colspan="2" align="center"><input type="submit" value="登录" />&nbsp;&nbsp;

                     <input type="reset" value="取消" /></td>
             </tr>
         </table>
     </form>

go30-1.jsp

  <h1 align="center">  <%=title%>  </h1>
      <h3 align="center">  <%=retn%>  </h3>

go30-2.jsp

 <h1 align="center">  <%=retn%>  </h1>
     <form  method="post">
     <table border="0" align="center" >
       <tr> <td>用户名</td><td> <input type="text" name="name"></td></tr>
       <tr><td>密码</td><td > <input type="password" name="pwd"> </td></tr>

       <tr><td colspan="2" align="center">
           <input type="submit" value="登录" />&nbsp;&nbsp;

           <input type="reset" value="取消" />
       </td></tr>
     </table>
     </form>

go30-3.jsp

 <h1 align="center">
         <%=retn%>
     </h1>
     <form method="post" action="<%=request.getContextPath() %>/servlet/goset">
         <input type="hidden" name="type" value="register">
         <table border="0" align="center">
             <tr>
                 <td>用户名</td>
                 <td><input type="text" name="name"></td>
             </tr>
             <tr>
                 <td>密码</td>
                 <td><input type="password" name="pwd"></td>
             </tr>
             <tr>
                 <td>邮箱</td>
                 <td><input type="text" name="email"></td>
             </tr>
             <tr>
                 <td>出生日期</td>
                 <td><input type="text" name="born"></td>
             </tr>
             <tr>
                 <td>性别</td>
                 <td>男<input type="radio" name="sex" value="男"> 女<input
                     type="radio" name="sex" value="女"></td>
             </tr>

             <tr>
                 <td colspan="2" align="center"><input type="submit" value="注册" />&nbsp;&nbsp;

                     <input type="reset" value="取消" /></td>
             </tr>
         </table>
     </form>

go30-4.jsp

 <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

  <table>
     <tr width="300">
     <td width="100">id</td>
     <td width="100">name</td>
     <td width="100">money</td>
     </tr>
     <c:forEach var="m" items= "${Model}">
     <tr>
     <td>${m.id}</td>
     <td>${m.name}</td>
     <td>${m.email}</td>

     </tr>
     </c:forEach>

     </table>

Product.jsp

 <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>

 <table>
     <tr width="500">
     <td width="100">id</td>
     <td width="100">name</td>
     <td width="100">pwd</td>
     <td width="100">email</td>
      <td width="100">born</td>
     <td width="100">sex</td>
     </tr>
     <c:forEach var="m" items= "${Model}">
     <tr>
     <td >${m.id}</td>
     <td >${m.name}</td>
     <td >${m.pwd}</td>
     <td >${m.email}</td>
      <td >${m.born}</td>
     <td >${m.sex}</td> 

     </tr>
     </c:forEach>

     </table>

UserLise.jsp