나는 다음과 같은 코드가 있습니다자바 하위 문자열?
String table;
private DB.ConnectMAS mas=new DB.ConnectMAS();
java.sql.ResultSet rs1 = mas.DBquery("select * from products");
try{
String duedate = "";
while(rs1.next()){
String duedate = rs1.getString("duedate");
table+="<tr><td>"+duedate.substring(1,10)+"</td></tr>";
} catch(java.sql.SQLException e){}
그것은 (1,10)
나는이 잘못된 이유를 이해하려고 노력 중이 야를 duedate.substring에 오류를 던지고을?
사전
에서 감사 오류 : 모든SEVERE: Servlet.service() for servlet POList threw exception
java.lang.NullPointerException
at POList.getDetails(POList.java:126)
at POList.getTable(POList.java:165)
at POList.processRequest(POList.java:55)
at POList.doGet(POList.java:177)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:690)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:210)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:174)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:834)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:640)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1286)
at java.lang.Thread.run(Unknown Source)
아마도 오류를 게시 하시겠습니까? – danben