用eclipse做一个简单的注册模块,输入用户名和密码,选择性别,按提交,将数据写如数据库,运行时出现的错误:
HTTP Status 500 - javax.servlet.ServletException: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'UserName' cannot be null
有时错误提示还会变成:
HTTP Status 500 - An exception occurred processing JSP page /registerProcess.jsp at line 7
代码是相同的,为什么会有不同的错误提示呢?
我的第七行代码:
org.apache.jasper.JasperException: An exception occurred processing JSP page /registerProcess.jsp at line 7
4: /jsp:useBean
5: /jsp:useBean
6: <%
7: database.register(userInfo);
8: response.sendRedirect("welcome.jsp");
9: %>
我理解是将前面输入的信息存入数据库的意思。
database类和register方法:
public class Database {
private static String url = "jdbc:mysql://localhost:3306/chapA";
private static String driver = "com.mysql.jdbc.Driver";
private static String userName = "root";
private static String password = "root";
private Connection connection;
//打开数据库连接
public Connection getConnection() throws ClassNotFoundException,SQLException {
Class.forName(driver);
connection = DriverManager.getConnection(url, userName, password);
return connection;
}
//关闭数据库连接
public void closeConnection() throws SQLException {
if(connection !=null && !connection.isClosed())
connection.close();
connection = null;
}
//注册
public void register(UserInfo userInfo) throws SQLException,ClassNotFoundException {
String sql = "insert into userinfo values(?,?,?);";
PreparedStatement ps = getConnection().prepareStatement(sql);
int i = 1;
ps.setString(i++, userInfo.getUserName());
ps.setString(i++, userInfo.getPassword());
ps.setString(i++, userInfo.getSex());
ps.executeUpdate();
closeConnection();
}
}
是不是我写的方法有问题?还是数据库没有连接好?我按书上一步一步做的,查了好几遍都没错呀。请各位大神指正啊!!
初学者,表达相当不专业,表达不清的地方请巨巨指出!需要看哪部分代码也请告诉我一下,我再往上贴。。
非常感谢!!!!跪谢!!!