网页的数据操作(增删改查)

接着上次的网页登陆之后，把跳转路径更改之后会显示数据的增删改查

此页面的数据来自Oracle数据库，自己建的一共三个，暂时用了两个，以下是数据库的添加数据

select * from subject;
select * from news;

--给新闻分类表添加7条数据
insert into subject values(1,'社会');
insert into subject values(2,'娱乐');
insert into subject values(3,'军事');
insert into subject values(4,'实事');
insert into subject values(5,'政治');
insert into subject values(6,'国内');
insert into subject values(7,'国际');


--给新闻表添加50条数据
declare
tid number:=1;
begin
  for i in 1..50 loop
    insert into news values(i,tid,'感人，真经'||i,'哇噻'||i,'这是一篇感人又震惊的新闻'||i,sysdate,0,'罗海妹又震惊了');
    tid:=tid+1;
    if tid>7 then
      tid:=1;
    end if;
  end loop;
end;

commit;

 点击左上角的添加新闻会到一个添加界面，让我们看看代码

 添加数据

request.setCharacterEncoding("utf-8");

	//接受添加数据
	//新闻编号
	int tid = Integer.valueOf(request.getParameter("ntid"));
	//新闻标题
	String ntitle = request.getParameter("ntitle");
	//新闻作者
	String nzz = request.getParameter("nauthor");
	//新闻摘要
	String nzy = request.getParameter("nsummary");
	//新闻内容
	String nnr = request.getParameter("ncontent");

	//连接数据库
	Class.forName("oracle.jdbc.OracleDriver");
	String url = "jdbc:oracle:thin:@localhost:1521:orcl";
	Connection con = DriverManager.getConnection(url, "scott", "scott");
	//获取下一个新闻的编号
	int nextNid = 1;
	PreparedStatement ps = con.prepareStatement("select max(nid) from news");
	ResultSet rs = ps.executeQuery();
	if (rs.next()) {
		nextNid = rs.getInt(1) + 1;
	}
	ps = con.prepareStatement("insert into news values(?,?,?,?,?,sysdate,0,?)");
	ps.setInt(1, nextNid);
	ps.setInt(2, tid);
	ps.setString(3, ntitle);
	ps.setString(4, nzz);
	ps.setString(5, nnr);
	ps.setString(6, nzy);
	//执行
	int i = ps.executeUpdate();
	if (i > 0) {
		out.print("<script>alert('添加成功');location.href='admin.jsp'</script>");
	} else {
		out.print("<script>alert('添加失败');location.href='add_news.jsp'</script>");
	}

绑定数据

 <%
          Class.forName("oracle.jdbc.OracleDriver");
      	String url = "jdbc:oracle:thin:@localhost:1521:orcl";
      	Connection con = DriverManager.getConnection(url, "scott", "scott");
         PreparedStatement ps = con.prepareStatement("select * from subject");
         ResultSet rs = ps.executeQuery();
         while(rs.next()){
         
          %>
          <option value='<%=rs.getInt(1) %>'> <%=rs.getString(2) %> </option>
          <%} %>

 删除数据

//删除的新闻编号
	String id = request.getParameter("nid");
	int nid = Integer.valueOf(id);
	Class.forName("oracle.jdbc.OracleDriver");
	String url = "jdbc:oracle:thin:@localhost:1521:orcl";
	Connection con = DriverManager.getConnection(url, "scott", "scott");
	PreparedStatement ps = con.prepareStatement("delete news where nid="+nid);
	int i = ps.executeUpdate();
	if(i>0){
		out.print("<script>alert('删除成功');location.href='admin.jsp'</script>");
	}else{
		out.print("<script>alert('删除失败');location.href='admin.jsp'</script>");
	}

修改数据

	request.setCharacterEncoding("utf-8");
int nid=Integer.valueOf(request.getParameter("nid"));
int tid=Integer.valueOf(request.getParameter("ntid"));
String ntitle=request.getParameter("ntitle");
String nzz=request.getParameter("nauthor");
String nzy=request.getParameter("nsummary");
String nnr=request.getParameter("ncontent");

Class.forName("oracle.jdbc.driver.OracleDriver");
Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORCL", "scott", "scott");
int nextNid=1;
PreparedStatement ps=con.prepareStatement("select max(nid) from news");
ResultSet rs=ps.executeQuery();
while(rs.next()){
	nextNid=rs.getInt(1)+1;
}

ps=con.prepareStatement("update news set ntitle=?,nrr=?,nzy=? where nid="+nid);
ps.setString(1, ntitle);
ps.setString(2, nnr);
ps.setString(3, nzy);

int i=ps.executeUpdate();
if(i>0){
	out.print("<script>alert(修改成功');location.href='admin.jsp'</script>");
}else{
	out.print("<script>alert('修改失败');location.href='update_news.jsp'</script>");
}