Question

jsp怎么在数据库中插入数据啊！！！

Class.forName("org.hsqldb.jdbcDriver");
String url = "jdbc:hsqldb:hsql://localhost/mydb";
String user = "sa";
String pwd = "";
Connection con = DriverManager.getConnection(url,user,pwd);
Statement stmt = con.createStatement();
String s1= request.getParameter("username");
String s2=request.getParameter("passwd");
String s3=request.getParameter("passconfirm");
String s4=request.getParameter("names");
String s5=request.getParameter("radiobutton");
String s6=request.getParameter("address");
String s7=request.getParameter("post");
String s8=request.getParameter("telphone");
String s9=request.getParameter("email");

这前面是我写的，后面的不会了- -，要判断原来数据库中是否存在有 username
Class.forName("org.hsqldb.jdbcDriver");
String url = "jdbc:hsqldb:hsql://localhost/mydb";
String user = "sa";
String pwd = "";
Connection con = DriverManager.getConnection(url,user,pwd);
Statement stmt = con.createStatement();
Statement st2 = con.createStatement();
String s1= request.getParameter("username");
String s2=request.getParameter("passwd");
String s3=request.getParameter("passconfirm");
String s4=request.getParameter("names");
String s5=request.getParameter("gender");
String s6=request.getParameter("address");
String s7=request.getParameter("post");
String s8=request.getParameter("telphone");
String s9=request.getParameter("email");

String sql="select * from MY_USERS where from username=s1";
ResultSet rs=stmt.executeQuery(sql);
if(!rs.next()){
rs.setString(1,s1);
rs.setString(2,s2);
rs.setString(3,s4);
rs.setString(4,s5);
rs.setString(5,s6);
rs.setString(6,s8);
rs.setString(7,s7);
rs.setString(8,s9);
}

现在已经到这样了，怎么还是有错哎```

Answer 1

标准的连接数库示例.
1.连接方法.
package t13;

import java.sql.*;

/**
*
* <p>Title: </p>
*
* <p>Description: </p>
*
* <p>Copyright: Copyright (c) 2008</p>
*
* <p>Company: </p>
*
* @author not attributable
* @version 1.0
*/
public class DAO {

public static Connection getCon(){
Connection con=null;//创建连接
String driver="com.microsoft.jdbc.sqlserver.SQLServerDriver";//连接驱动
String url="jdbc:microsoft:sqlserver://127.0.0.1:1433;DatabaseName=pubs";//连接字符串
String user="sa";//连接用户名
String pwd="";//连接密码
try {
Class.forName(driver);
} catch (ClassNotFoundException ex) {
System.out.println("数据库连接驱动加载错误,错误信息如下：");
ex.printStackTrace();
}
try {
con = DriverManager.getConnection(url, user, pwd);
} catch (SQLException ex1) {
System.out.println("创建数据库连接出错，错误信息如下：");
ex1.printStackTrace();
}

return con;
}
}
2.数据库操作方法.
package t13;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class DBManage {

public List selectStores() {
Connection con = DAO.getCon(); //获得连接
PreparedStatement pst = null;
ResultSet rs = null;
List list = new ArrayList();
String sql = "select * from stores";
try {
pst = con.prepareStatement(sql);
rs = pst.executeQuery();
while (rs.next()) {
StoresBean temp = new StoresBean();
temp.setStor_id(rs.getInt("stor_id"));
temp.setStor_name(rs.getString("stor_name"));
temp.setStor_address(rs.getString("stor_address"));
temp.setCity(rs.getString("city"));
temp.setState(rs.getString("state"));
temp.setZip(rs.getString("zip"));
list.add(temp);
}
} catch (SQLException ex) {
System.out.println("DBManager类中的selectStores方法出错，错误信息如下：");
ex.printStackTrace();
} finally {
try {
rs.close();
pst.close();
con.close();
} catch (Exception e) {
System.out.println("DBManager类中的关闭数据库出错，错误信息如下：");
e.printStackTrace();
}
}
return list;
}

// public static void main(String[] args) {
// DBManage dbm=new DBManage();
// List list=dbm.selectStores();
// for(int i=0;i<list.size();i++){
// StoresBean ss=(StoresBean)list.get(i);
// System.out.println(ss.getStor_id()+"---"+ss.getStor_name()+"---"+ss.getStor_address());
// }
// }
}
3.javabean.
package t13;

public class StoresBean {
private int stor_id;
private String stor_name;
private String stor_address;
private String city;
private String state;
private String zip;
public String getCity() {
return city;
}

public String getState() {
return state;
}

public String getStor_address() {
return stor_address;
}

public int getStor_id() {
return stor_id;
}

public String getStor_name() {
return stor_name;
}

public String getZip() {
return zip;
}

public void setCity(String city) {
this.city = city;
}

public void setState(String state) {
this.state = state;
}

public void setStor_address(String stor_address) {
this.stor_address = stor_address;
}

public void setStor_id(int stor_id) {
this.stor_id = stor_id;
}

public void setStor_name(String stor_name) {
this.stor_name = stor_name;
}

public void setZip(String zip) {
this.zip = zip;
}

}
这是一个完整的程序.

Answer 2

where name=?

你写进去 的名称!

判断数据库是否有这个名字!

有就不插入..没有就插入

Answer 3

楼上这位用的是MVC模式，估计楼主现在还不会用