《JavaWeb编程技术》课后习题答案(10)
时间:2025-07-10
时间:2025-07-10
ResultSet.TYPE_SCROLL_SENSITIVE
ResultSet.TYPE_SCROLL_INSENSITIVE
第二个参数使用下面常量:
ResultSet.CONCUR_UPDATABLE
6. 参考程序如下:
package com.control;
import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class BookQueryServlet extends HttpServlet{
Connection dbconn;
public void init() {
String driver = "org.postgresql.Driver";
String dburl = "jdbc:postgresql://127.0.0.1:5432/bookstore";
String username = "bookstore";
String password = "bookstore";
try{
Class.forName(driver);
dbconn = DriverManager.getConnection(
dburl,username,password);
}catch(ClassNotFoundException e1){
}catch(SQLException e2){}
}
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException,IOException{
response.setContentType("text/html;charset=gb2312");
PrintWriter out = response.getWriter();
out.println("<html><body>");
out.println("<table>");
try{
String sql="SELECT * FROM books";
Statement stmt = dbconn.createStatement();
ResultSet rst = stmt.executeQuery(sql);
while(rst.next()){
out.println("<tr><td>"+rst.getString(1)+"</td>");
out.println("<td>"+rst.getString(2)+"</td>");
out.println("<td>"+rst.getString(3)+"</td>");
out.println("<td>"+rst.getString(4)+"</td>");
out.println("<td>"+rst.getDouble(5)+"</td></tr>");
}
}catch(SQLException e){
e.printStackTrace();
}
out.println("</table>");
out.println("</body></html>");
}