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分享空指针问题？？？急
空指针 但是为什么 我把我的.jsp and bean paste 出来了帮我看看，谢谢了
java.lang.NullPointerException
myfirstbean.DataOperate.insertSQLCommand(DataOperate.java:96)
org.apache.jsp.register_jsp._jspService(register_jsp.java:87)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
rigister.jsp
<html>
<body>
<%@page language="java"%>
<form method="post" action="insertNews.jsp" enctype="multipart/form-data">
<%@ page import="java.lang.*"%>
<jsp:useBean id="dataOperate" class="myfirstbean.DataOperate"/>
<%
dataOperate.openConnection();
String name,Anonymous,email,descrip,num,cod;
int code,telnumber;
cod=request.getParameter("co");
num=request.getParameter("telnumb");
name=request.getParameter("na");
Anonymous=request.getParameter("Anonymo");
descrip=request.getParameter("descr");
code=Integer.parseInt(cod);
telnumber=Integer.parseInt(num);
email=request.getParameter("ema");
System.out.println(name);
System.out.println(Anonymous);
dataOperate.setName(name);dataOperate.setAnonymous(Anonymous);dataOperate.setCode(code);
dataOperate.setEmail(email);dataOperate.setTel(telnumber);dataOperate.setDescription(descrip);
String inSertCommand="insert into Customer Values('"+dataOperate.getName()+"','"+dataOperate.getAnonymous()+"',"+dataOperate.getCode()+",'"+dataOperate.getEmail()+"',"+dataOperate.getNumber()+",'"+dataOperate.getDescription()+"')";
String execut="inSertCommand ";
dataOperate.insertSQLCommand(execut );
%>
<%out.print("注册成功，恭喜你");%>
</form>
</body>
</html>
package myfirstbean;
import java.sql.*;
public class DataOperate{
Connection theConnection;
Statement theStatement;
ResultSet theResult;
String theDataSource,theUser,thePassword,theName,theAnonymous,
theEmail,description,insertCommand;
int telNumb,theCode;
//设置和获得参数
public void setName(String name){
theName=name;
}
public String getName(){
return theName;
}
public void setAnonymous(String Anonymous){
theAnonymous=Anonymous;
}
public String getAnonymous(){
return theAnonymous;
}
public void setCode(int code){
theCode=code;
}
public int getCode(){
return theCode;
}
public void setEmail(String email){
theEmail=email;
}
public String getEmail(){
return theEmail;
}
public void setTel(int telnumber){
telNumb= telnumber;
}
public int getNumber(){
return telNumb;
}
public void setDescription(String descrip){
description=descrip;
}
public String getDescription(){
return description;
}
static void openConnection(){
theDataSource= "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=mydata";
theUser="sa";
thePassword=" ";
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
theConnection=DriverManager.getConnection(theDataSource,theUser,thePassword);
theStatement=theConnection.createStatement();
}catch(Exception e){
e.printStackTrace();
System.out.println("Error Trace in getConnection() : " + e.getMessage());
}
}
static void insertSQLCommand(String inSertCommand){
try{
theResult=theStatement.executeQuery(inSertCommand);
}catch(SQLException e){ e.printStackTrace();
System.out.println("Error Trace in executeQuery() : " + e.getMessage());
}
}
}
java.lang.NullPointerException
myfirstbean.DataOperate.insertSQLCommand(DataOperate.java:96)
org.apache.jsp.register_jsp._jspService(register_jsp.java:87)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
rigister.jsp
<html>
<body>
<%@page language="java"%>
<form method="post" action="insertNews.jsp" enctype="multipart/form-data">
<%@ page import="java.lang.*"%>
<jsp:useBean id="dataOperate" class="myfirstbean.DataOperate"/>
<%
dataOperate.openConnection();
String name,Anonymous,email,descrip,num,cod;
int code,telnumber;
cod=request.getParameter("co");
num=request.getParameter("telnumb");
name=request.getParameter("na");
Anonymous=request.getParameter("Anonymo");
descrip=request.getParameter("descr");
code=Integer.parseInt(cod);
telnumber=Integer.parseInt(num);
email=request.getParameter("ema");
System.out.println(name);
System.out.println(Anonymous);
dataOperate.setName(name);dataOperate.setAnonymous(Anonymous);dataOperate.setCode(code);
dataOperate.setEmail(email);dataOperate.setTel(telnumber);dataOperate.setDescription(descrip);
String inSertCommand="insert into Customer Values('"+dataOperate.getName()+"','"+dataOperate.getAnonymous()+"',"+dataOperate.getCode()+",'"+dataOperate.getEmail()+"',"+dataOperate.getNumber()+",'"+dataOperate.getDescription()+"')";
String execut="inSertCommand ";
dataOperate.insertSQLCommand(execut );
%>
<%out.print("注册成功，恭喜你");%>
</form>
</body>
</html>
package myfirstbean;
import java.sql.*;
public class DataOperate{
Connection theConnection;
Statement theStatement;
ResultSet theResult;
String theDataSource,theUser,thePassword,theName,theAnonymous,
theEmail,description,insertCommand;
int telNumb,theCode;
//设置和获得参数
public void setName(String name){
theName=name;
}
public String getName(){
return theName;
}
public void setAnonymous(String Anonymous){
theAnonymous=Anonymous;
}
public String getAnonymous(){
return theAnonymous;
}
public void setCode(int code){
theCode=code;
}
public int getCode(){
return theCode;
}
public void setEmail(String email){
theEmail=email;
}
public String getEmail(){
return theEmail;
}
public void setTel(int telnumber){
telNumb= telnumber;
}
public int getNumber(){
return telNumb;
}
public void setDescription(String descrip){
description=descrip;
}
public String getDescription(){
return description;
}
static void openConnection(){
theDataSource= "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=mydata";
theUser="sa";
thePassword=" ";
try{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
theConnection=DriverManager.getConnection(theDataSource,theUser,thePassword);
theStatement=theConnection.createStatement();
}catch(Exception e){
e.printStackTrace();
System.out.println("Error Trace in getConnection() : " + e.getMessage());
}
}
static void insertSQLCommand(String inSertCommand){
try{
theResult=theStatement.executeQuery(inSertCommand);
}catch(SQLException e){ e.printStackTrace();
System.out.println("Error Trace in executeQuery() : " + e.getMessage());
}
}
}
...全文
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xtuyaowu 2005-04-09
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问题出在: 但调不好 我不用bean 完全 能够解决 但是 如果加如大量代码的话 不太科学!!!
dataOperate.insertSQLCommand(execut );
dataOperate.insertSQLCommand(execut );
galewithwing 2005-04-08
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应该是你的某个对象或者参数为空,引用的时候就出错了,
你在程序中加一些调试信息就可以定位了
你在程序中加一些调试信息就可以定位了
bitou 2005-04-08
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String execut="inSertCommand ";
dataOperate.insertSQLCommand(execut );
效果是这样：
dataOperate.insertSQLCommand("inSertCommand ");//这不是你所期望的
另外，你把这句
dataOperate.openConnection();
放在了最前面，而直到最后才引用到它，这个习惯不太好
dataOperate.insertSQLCommand(execut );
效果是这样：
dataOperate.insertSQLCommand("inSertCommand ");//这不是你所期望的
另外，你把这句
dataOperate.openConnection();
放在了最前面，而直到最后才引用到它，这个习惯不太好
kigoqzw 2005-04-08
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String execut="inSertCommand ";
莫名
莫名
fashchina 2005-04-08
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String execut="inSertCommand ";
dataOperate.insertSQLCommand(execut );
这个什么意思
就直接用
dataOperate.insertSQLCommand(inSertCommand);
确保sql没错,和值都传对
真不明白你什么意思
来个这个:String execut="inSertCommand ";
dataOperate.insertSQLCommand(execut );
这个什么意思
就直接用
dataOperate.insertSQLCommand(inSertCommand);
确保sql没错,和值都传对
真不明白你什么意思
来个这个:String execut="inSertCommand ";
