用MVC模式从数据库中取数据的例子1、 在数据库中建立一张表单
2.1 写个封装连接数据库所需要属性的bean <DbAction>
2.2 写个封装表里属性的bean <UserAction>
2.3 写个连接数据库的bean <DbBean>,用LIST存储数据
3、 写个查询的servlet <QueryServlet>
4、 写个JSP页面.<query.jsp>其中第2.3 和3 该怎么写啊 ?能讲讲整个思想吗?
非常感谢!!!
2.1 写个封装连接数据库所需要属性的bean <DbAction>
2.2 写个封装表里属性的bean <UserAction>
2.3 写个连接数据库的bean <DbBean>,用LIST存储数据
3、 写个查询的servlet <QueryServlet>
4、 写个JSP页面.<query.jsp>其中第2.3 和3 该怎么写啊 ?能讲讲整个思想吗?
非常感谢!!!
在Hibernate里可以封装表里属性的bean
我也是这本书入门的
《2.1》 import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
//数据库连接
public class Db {
public static Connection con(){
Connection con=null;
String driver= "com.microsoft.jdbc.sqlserver.SQLServerDriver ";
String url= "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=jspdev ";
String dbname= "sa ";
String dbpass= "sa ";
try{
Class.forName(driver);
con=DriverManager.getConnection(url,dbname,dbpass);
}catch(ClassNotFoundException e){
e.printStackTrace();
}catch( SQLException e){
e.printStackTrace();
}
return con;
}
public static void main(String[] agrs)
{
Db i=new Db();
System.out.println( "con= "+i.con());
}
}
《2.2》
import java.io.Serializable; public class UserInfo implements Serializable{
private String username;
private String pass;
private String sex;
public String getPass() {
return pass;
}
public void setPass(String pass) {
this.pass = pass;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
@Override
public String toString() {
StringBuffer bf=new StringBuffer();
bf.append( "username= ");
bf.append(username);
bf.append( ":pass= ");
bf.append(pass);
bf.append( ":sex= ");
bf.append(sex);
return bf.toString();
}
}
《2.3》
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List; import domain.Db;
import domain.UserInfo;
public class DbBean{
public static List getuserlist() {
//得到数据库连接
Db conn=new Db();
Connection con=conn.con();
List <UserInfo> userlist=new ArrayList <UserInfo> ();
PreparedStatement stmt=null;
ResultSet rs=null;
try {
stmt=con.prepareStatement( "select * from user_table ");
rs=stmt.executeQuery();
while(rs.next()){
UserInfo userinfo=new UserInfo();
userinfo.setUsername(rs.getString( "username "));
userinfo.setPass(rs.getString( "pass "));
userinfo.setSex(rs.getString( "sex "));
userlist.add(userinfo);
}
}
catch (SQLException e) {
e.printStackTrace();
}
return userlist;
}
public static void main(String[] agrs)
{
UserInfo userinfo = new UserInfo();
List userlist=DbBean.getuserlist();
System.out.println( "userlist= "+userlist.size());
}
} 《3》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 dao.DbBean;
import domain.UserInfo; public class GetListServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { doPost(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
DbBean db=new DbBean();
List userlist=db.getuserlist();
request.setAttribute( "userlist ", userlist);
request.getRequestDispatcher( "/query.jsp ").forward(request,response);
}
}