这是我的代码：
package JspServletMysql;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletRegist extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String driver = "com.mysql.jdbc.Driver";
String url = "jdbc:mysql://localhost:3306/test"; // 把SC换成你要连接的数据库的名字
String username = "root"; // user_name代表数据库用户的名称
String sql = "insert into person(id,psword) values(?,?)";
String password = "root";
boolean result;
Connection conn = null;
request.setCharacterEncoding("UTF-8");
String id = request.getParameter("id");
String psword = request.getParameter("psword");
try {
Class.forName(driver);
conn = DriverManager.getConnection(url, username, password);
PreparedStatement pstmt = conn.prepareStatement(sql);
pstmt.setString(1, id);
pstmt.setString(2, psword);
pstmt.execute();
pstmt.close();
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
out.println("<HTML>");
out.println(" <HEAD><TITLE>tableone input page</TITLE></HEAD>");
out.println(" <BODY>");
out.println("注册成功");
out.println("<a href=\"" + request.getContextPath()
+ "/index.jsp\">重新注册</a>");
out.println(" </BODY>");
out.println("</HTML>");
out.flush();
out.close();
}
}
运行后报出这样的异常：
com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Column 'psword' cannot be null
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
at com.mysql.jdbc.Util.getInstance(Util.java:381)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:956)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3515)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3447)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1951)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2101)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2554)
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1761)
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1021)
at JspServletMysql.ServletRegist.doPost(ServletRegist.java:40)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:857)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:722)
请教这该如何解决？
------解决方案--------------------
String psword = request.getParameter("psword"); 获取到的psword为null
看看你页面上是不是没有传过来 或者名字有没有写对
------解决方案--------------------
MySQLIntegrityConstraintViolationException: Column 'psword' cannot be null
检查 String psword = request.getParameter("psword"); 是否取到值，