添加信息项目流程
1． javaBean:
a.Stu.java: public class Stu {private String name,sex,myclass; private int age;
public void setName(String nm){name=nm;} public String getName(){return name; }
b.DBContext.java: import java.sql.*;import sun.jdbc.odbc.*; public class DBContext {
public static final DBContext getInstance=new DBContext (); //静态可共享连接
public Connection getConnection(){ try{ Class.forName("Driver");
Connection conn=DriverManager.getConnection(url,user,password);
System.out.println("连接成功！"); return conn; } //getConnection要返回个Conn类
catch(Exception e){e.printStackTrace();return null;}}}
c.DBBean.java: import java.sql.*; public class DBBean {
Connection conn=null; ResultSet rs=null;
public ResultSet executeQuery(String sql){ rs=null;
try{ conn=DBContext.getInstance.getConnection();
Statement stmt=conn.createStatement(); rs=stmt.executeQuery(sql); }
catch(SQLException ex){ex.getMessage();} return rs; }//代替方法体里面return
public int executeUpdate(String sql){
try{ conn=DBContext.getInstance.getConnection();
Statement stmt=conn.createStatement();int i=stmt.executeUpdate(sql);
if(i>0) System.out.println("update success!:"+i);
else System.out.println("update error!"); return i; }
catch(Exception ex){ ex.printStackTrace(); return -1; } }
public void closeConnection(){
try{ if(!conn.isClosed()) conn.close();}//检索connection对象是否被关闭
catch(Exception ex){ ex.printStackTrace();} }
进行测试：public static void main(String[] args){DBBean dbo=new DBBean();
ResultSet rs=dbo.executeQuery("select *from mytalbe");
try{ while(rs.next()){if(rs.getString("name")!=null){
System.out.println(rs.getString("name").toString());}} }
catch(Exception ex){ ex.printStackTrace();}}}
2． 添加信息块：insertStu.jsp:<%@ include file="stuManager.jsp"%>
添加测试：<jsp:useBean id="stu" scope="page" class="Stu"/>
<jsp:setProperty name="stu" property="*"/>
<jsp:useBean id="DBbean" scope="page" class=" DBBean"/>
<%String name=stu.getName();String sex=stu.getSex();int age=stu.getAge();
String myclass=stu.getMyclass();
String sql="insert into mytable(name,sex,age,myclass)
values("+"'"+name+"',"+"'"+sex+"',"+"'"+age+"',"+"'"+myclass+"'"+")";
int i=DBbean.executeUpdate(sql); if(i>0){ out.println("insert success!"); }
else{ out.println("insert error!"); }%>
3．查询信息块(表头如图)：<jsp:useBean id="DBbean" scope="page" class=" DBBean"/>
<% ResultSet rs=DBbean.executeQuery("select * from mytable"); %>
<% while(rs.next()){ %> <tr>
<td height="23"><div align="center"><%= rs.getString("name") %></div></td>
<td><div align="center"><%= rs.getString("sex") %></div></td>
<td><div align="center"><%= rs.getString("age") %></div></td>
<td><div align="center"><%= rs.getString("myclass") %></div></td>
<td><div align="center"><a href="delete.jsp?
id=<%= rs.getInt("id") %>">delete</a></div></td>
<td><div align="center"><a href="update.jsp?
id=<%= rs.getInt("id") %>">update</a></div></td>
</tr> <% } %>
4． 删除信息块：<jsp:useBean id="DBbean" scope="page" class=" DBBean"/>
<% String n=request.getParameter("id"); //selectStu的href(id)
String sql="delete from mytable where id='"+n+"'";
int i=DBbean.executeUpdate(sql);
if(i>0) { response.sendRedirect("selectStu.jsp");} else {out.print("失败!");} %>
5．更新信息块（表单如图）：<jsp:useBean id="DBbean" scope="page" class=" DBBean"/>
<% String n=request.getParameter("id");//selectStu的href(id)
ResultSet rs=DBbean.executeQuery("select *from mytable where id='"+n+"'");
if(rs!=null) rs.next(); %>//返回到第一个记录之上，所以一定要取next的值
测试更新(提交id)：<jsp:useBean id="DBbean" scope="page" class=" DBBean"/>
<% String name=stu.getName();String sex=stu.getSex(); int age=stu.getAge();
String myid=request.getParameter("id");String myclass=stu.getMyclass();
String sql="update mytable set name='"+name+"',sex='"+sex+"',
age='"+age+"',myclass='"+myclass+"' where id="+myid;
int i=DBbean.executeUpdate(sql);
if(i>0){ out.println("更新成功！");response.sendRedirect("selectStu.jsp"); }
else { out.print("error!");} %>