生成隨機不,我已經寫了這樣的代碼,但它給exceptions.actually我要生成一個隨機value.save到數據庫中,並返回給用戶問題在Java
import java.math.BigInteger;
import java.security.SecureRandom;
public static String recoverpassword(String uid,String ans) {
try {
verifyans.setString(1,uid);
verifyans.setString(2,ans);
ResultSet resultSet = verifyans.executeQuery();
if (resultSet.next()) {
SecureRandom random = new SecureRandom();
String newpass = new BigInteger(130, random).toString(32);
resetpass.setString(1,newpass);
resetpass.setString(2,uid);
resetpass.executeUpdate();
return newpass;
} else {
return "xxx";
}
} catch(Exception e) {
System.out.println("exception" +e);
e.printStackTrace();
return "xxx";
}
}
IM獲得空指針異常,如:
[email protected]]
exceptionjava.lang.NullPointerException
java.lang.NullPointerException
at org.tranql.connector.jdbc.ConnectionHandle.connectionError(ConnectionHandle.java:103)
at org.tranql.connector.jdbc.PreparedStatementHandle.executeUpdate(PreparedStatementHandle.java:105)
at com.ibm.lims.LimsHandler.recoverpassword(LimsHandler.java:940)
at org.apache.jsp.recoverpasswordresult_jsp._jspService(recoverpasswordresult_jsp.java:78)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:342)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:267)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
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.geronimo.tomcat.valve.DefaultSubjectValve.invoke(DefaultSubjectValve.java:56)
at org.apache.geronimo.tomcat.GeronimoStandardContext$SystemMethodValve.invoke(GeronimoStandardContext.java:406)
at org.apache.geronimo.tomcat.valve.GeronimoBeforeAfterValve.invoke(GeronimoBeforeAfterValve.java:47)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:567)
at org.apache.geronimo.tomcat.valve.ThreadCleanerValve.invoke(ThreadCleanerValve.java:40)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Unknown Source)
嘿,我測試的代碼去除那些SecureRandom的類call.i只是像「樣本」雙引號傳遞一個字符串值,並將它的工作。意味着問題出現在securerandom類中。我認爲值在字符串值字段中以整數形式出現,因此數據庫服務器正在發送異常。 PLZ給我一些代碼來產生隨機字符串交替 -
你忘記告訴例外。順便說一下,不知道這是否僅僅是一個虛擬示例,但是您發佈的JDBC代碼肯定不是線程安全的並且是資源泄漏安全的。它可能會導致問題,只有在沒有關於異常/追蹤的信息時才能判斷。 – BalusC 2010-01-07 11:42:17
問題是什麼?請更具體一些。 – 2010-01-07 11:42:27
即時獲取空指針異常 – 2010-01-07 11:52:22