《Javaee架构与应用》实验大纲与实验指导2015

import java.sql.*;

public class SqlSrvDBConn {

private Statement stmt; private Connection conn; ResultSet rs;

//在构造方法中创建数据库连接 public SqlSrvDBConn(){ stmt=null; try{ 456\

Class.forName(\String uri = \

conn = DriverManager.getConnection(uri, \ }catch(Exception e){ } rs=null; }

//执行查询类的SQL语句，有返回集 public ResultSet executeQuery(String sql) { try { E);

rs=stmt.executeQuery(sql); }catch(SQLException e){

System.err.println(\ } return rs; } //关闭对象

stmt=conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABL

e.printStackTrace();

/**加载并注册 MySQL的 JDBC 驱动*/ /**加载并注册 SQLServer 2008 的 JDBC 驱动*/

//Class.forName(\

//conn=DriverManager.getConnection(\

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public void closeStmt() { try {

stmt.close(); }catch(SQLException e){

System.err.println(\ } }

public void closeConn() { try {

conn.close(); }catch(SQLException e){

System.err.println(\ } } }

【2】UserTable.java

package org.easybooks.test.model.vo; public class UserTable {

private Integer id; private String username; private String password;

public Integer getId(){ }

public void setId(Integer id){ }

public String getUsername(){ }

public void setUsername(String username){ }

this.username=username; return this.username; this.id=id; return this.id;

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}

public String getPassword(){ }

public void setPassword(String password){ }

this.password=password; return this.password;

（5）编写Servlet

package org.easybooks.test.servlet; import java.sql.*; import java.io.*; import javax.servlet.*; import javax.servlet.http.*;

import org.easybooks.test.jdbc.SqlSrvDBConn; import org.easybooks.test.model.vo.UserTable;; public class MainServlet extends HttpServlet{

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{

request.setCharacterEncoding(\

//设置请求编码 //获取提交的用户名 //获取提交的密码 //验证成功标识

String usr=request.getParameter(\ String pwd=request.getParameter(\ boolean validated=false;

SqlSrvDBConn sqlsrvdb=new SqlSrvDBConn();

HttpSession session=request.getSession(); //获得会话对象，用来保存当前登录用户的信息 UserTable user=null;

//先获得UserTable对象，如果是第一次访问该页，用户对象肯定为空，但如果是第二次甚至是第三次，

//就直接登录主页而无须再次重复验证该用户的信息 user=(UserTable)session.getAttribute(\

//如果用户是第一次进入，会话中尚未存储user持久化对象，故为null if(user==null){

//查询userTable表中的记录

//取得结果集

String sql=\

ResultSet rs=sqlsrvdb.executeQuery(sql);

try {

while(rs.next()) {

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if((rs.getString(\compareTo(pwd)==0)){

}

}

sqlsrvdb.closeStmt(); sqlsrvdb.closeConn(); }

else{

validated=true; }

if(validated) {

//验证成功跳转到main.jsp response.sendRedirect(\ } else{

//验证失败跳转到error.jsp response.sendRedirect(\ }

}

public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{ }

（6）配置Servlet

Servlet编写完成后，必须在项目web.xml中进行配置方可使用。 修改项目web.xml

}

doGet(request,response);

//该用户在之前已登录过并成功验证，故标识为true表示无须再验了

rs.close();

} catch (SQLException e) {

e.printStackTrace();

user=new UserTable(); user.setId(rs.getInt(1));

user.setUsername(rs.getString(2)); user.setPassword(rs.getString(3)); session.setAttribute(\validated=true; }

//把user对象存储在会话中 //标识为true表示验证成功通过 //创建持久化的JavaBean对象user

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