mainAction.javaString mid;
try {
mid=request.getParameter("mid");
Connection con=connectionFactory.getconnection();
String sql="select name,content,index_image_url from main where id=?";
PreparedStatement ps=con.prepareStatement(sql);
ps.setString(1,mid);
ResultSet rs=ps.executeQuery();
rs.next();
mainForm mf=new mainForm();
mf.setName(rs.getString(1));
mf.setContent(rs.getString(2));
mf.setIndex_image_url(rs.getString(3));
request.setAttribute("mf", mf);String mid;
try {
mid=request.getParameter("mid");
Connection con=connectionFactory.getconnection();
String sql="select name,content,index_image_url from main where id=?";
PreparedStatement ps=con.prepareStatement(sql);
ps.setString(1,mid);
ResultSet rs=ps.executeQuery();
rs.next();
mainForm mf=new mainForm();
mf.setName(rs.getString(1));
mf.setContent(rs.getString(2));
mf.setIndex_image_url(rs.getString(3));
request.setAttribute("mf", mf);
尤其是ps.setString(1,mid);这部分不太理解!
在main.jsp部分有<ul>
<li><a href="main.do?mid=2">公司简介</a></li>
<li><a href="main.do?mid=3">业务介绍</a></li>
<li><a href="main.do?mid=4">企业资质</a></li>
<li><a href="main.do?mid=5">大事记</a></li>
</ul>
try {
mid=request.getParameter("mid");
Connection con=connectionFactory.getconnection();
String sql="select name,content,index_image_url from main where id=?";
PreparedStatement ps=con.prepareStatement(sql);
ps.setString(1,mid);
ResultSet rs=ps.executeQuery();
rs.next();
mainForm mf=new mainForm();
mf.setName(rs.getString(1));
mf.setContent(rs.getString(2));
mf.setIndex_image_url(rs.getString(3));
request.setAttribute("mf", mf);String mid;
try {
mid=request.getParameter("mid");
Connection con=connectionFactory.getconnection();
String sql="select name,content,index_image_url from main where id=?";
PreparedStatement ps=con.prepareStatement(sql);
ps.setString(1,mid);
ResultSet rs=ps.executeQuery();
rs.next();
mainForm mf=new mainForm();
mf.setName(rs.getString(1));
mf.setContent(rs.getString(2));
mf.setIndex_image_url(rs.getString(3));
request.setAttribute("mf", mf);
尤其是ps.setString(1,mid);这部分不太理解!
在main.jsp部分有<ul>
<li><a href="main.do?mid=2">公司简介</a></li>
<li><a href="main.do?mid=3">业务介绍</a></li>
<li><a href="main.do?mid=4">企业资质</a></li>
<li><a href="main.do?mid=5">大事记</a></li>
</ul>
Connection con=connectionFactory.getconnection(); //获取数据库连接
String sql="select name,content,index_image_url from main where id=?"; //要执行的SQL语句
PreparedStatement ps=con.prepareStatement(sql);
ps.setString(1,mid); //替换上面SQL语句中的 id=? 的?值
ResultSet rs=ps.executeQuery(); //执行查询
rs.next(); //游标跳到第一条记录
mainForm mf=new mainForm();
mf.setName(rs.getString(1)); //从记录集中读取name 并设置到mf对象中的name属性
mf.setContent(rs.getString(2)); //以此类推
mf.setIndex_image_url(rs.getString(3));
request.setAttribute("mf", mf);
pstmt的set方法
pstmt.setString(n, str);
是将conn.prepareStatement(sql)中sql的第n个问号内容用str代替,这个可以查API
例如
String username = test;
String password = testtest;
String sql = "select * from user u where u.username = ? and u.password = ?";
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, username);
pstmt.setString(2, password);
ResultSet rs = pstmt.executeQuery();
... ...