Servlet中调用数据库
Oracel
ResultSet rs = ps.executeQuery();
while(rs.next()){
rs.getInt(1)
rs.getString(4)
}
// 从数据库中取验证
Connection ct = null;
ResultSet rs = null;
PreparedStatement ps = null;
try {
// 1加载驱动
Class.forName("oracle.jdbc.driver.OracleDriver");
// 2得到连接
ct = DriverManager.getConnection(
"jdbc:oracle:thin:@127.0.0.1:1521:orcl", "scott", "tiger");
// 3创建PrepareStatement
ps = ct.prepareStatement("select * from users where id=? and passwd=?");
// 给?赋值
ps.setObject(1, id);
ps.setObject(2, pwd);
// 4执行操作
rs = ps.executeQuery();
// 5根据结果处理
if (rs.next()) {
// 说明该用户合法
request.getRequestDispatcher("/MainFrame").forward(request,
response);
} else {
request.setAttribute("errno", "用户名密码错误");
request.getRequestDispatcher("/LoginServlet").forward(request,
response);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭资源
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
rs = null;
}
if (ps != null) {
try {
ps.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ps = null;
}
if (ct != null) {
try {
ct.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
ct = null;
}
}
MySQL
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/Chatsql","root","root");
Statement state = conn.createStatement();
String sql="select password from usr where name='"+usr+"'";
String sql2="update usr set isLogin=1 where name='"+usr+"'";
ResultSet res = state.executeQuery(sql);
while(res.next()) {
String tmp = res.getString("password");
if(tmp.equals(passwd)) {
System.out.println(usr+"登陆成功");
int count = state.executeUpdate(sql2);
System.out.println("更新了"+count+"条数据");
res.close();
state.close();
conn.close();
return true;
}
}
res.close();
state.close();
conn.close();
return false;
