java.lang.NumberFormatException: For input string: ""报错，求大家帮助

Question

java.lang.NumberFormatException: For input string: ""
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:504)
at java.lang.Integer.parseInt(Integer.java:527)
at org.apache.jsp.cart_005fadd_jsp._jspService(cart_005fadd_jsp.java:68)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
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 Servlet.SetCharacterEncoding.doFilter(SetCharacterEncoding.java:43)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
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:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:602)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:729)代码如下：
        String goodsID=request.getParameter("fruit_id1");
String goodsPrice=request.getParameter("price");
System.out.print(goodsID);
System.out.print(goodsPrice);
int goodsId=Integer.parseInt(goodsID);
float goodsprice=Integer.parseInt(goodsPrice);

Answer 1

这是页面报错结果：type Exception reportmessagedescription The server encountered an internal error () that prevented it from fulfilling this request.exceptionorg.apache.jasper.JasperException: An exception occurred processing JSP page /cart_add.jsp at line 129:  System.out.print(goodsID);
10:  System.out.print(goodsPrice);
11: 
12:  int goodsId=Integer.parseInt(goodsID);
13:  float goodsprice=Integer.parseInt(goodsPrice);
14: 
15: Goods goods=new Goods(

Answer 2

第一，确保fruit_id1参数是有数据的，而且是数值。
第二，int goodsId=Integer.parseInt(goodsID.trim());
这样试试

Answer 3

12: int goodsId=Integer.parseInt(goodsID);⇒
if ( goodsID == null || "".equals(goodsID.trim())) {
    throw new RuntimeException("XXXXX");
}
int goodsId=Integer.parseInt(goodsID);
第１３行一样也要修改

Answer 4

float goodsprice=Integer.parseInt(goodsPrice);
这个有问题吧，
Integer.parseInt(goodsPrice);这句话转化以后是int类型的，你赋值给的goodsprice是float类型，能对吗？
还有你哪个报错貌似是java.lang.NumberFormatException: For input string: ""
这个貌似是 没接收到东西，为空了吧

Answer 5

debug 跟踪一下，看看有值没

Answer 6

在获取页面参数时，做一下判断即可，如下：
String goodsID=request.getParameter("fruit_id1");
String goodsPrice=request.getParameter("price");
int goodsId;
float goodsprice;
if(goodsID==null||goodsID==""){
    goodsId=0;
}else{
   goodsId=Integer.parseInt(goodsID);
}
if(goodsPrice==null||goodsPrice==""){
  goodsprice=0;
}else{
   goodsprice=Integer.parseInt(goodsPrice);
}

Answer 7

估计是传参，你先做跳转呢，不要get值，在在跳转中，try catch，看下在哪里错了到 这样判断范围宽了

Answer 8

int goodsId=Integer.parseInt(goodsID);这行出错 因为goodsID为"", 转成int时出现类型转换错误