一个小问题，关于select标签下option的value参数提交后台数据出错的问题

Question

简单的网页提交参数给后台程序处理：

网页request提交的表单数据如图：

上面是chrome抓取到的表单提交参数，是由select标签option中的value属性值提交出来的一个数组；

我在myeclipse中debug如图：

发现其他参数均正常提交，唯有此参数为空，我在接受表单参数的Action定义Integer[] sids;另外，我以为是类型型问题，也尝试改成char[],String,来定义sids,均获取为空，在此求教各位，先谢谢了！！

Answer 1

这个看着没问题啊，话说传到后台的参数不是应该是sids:xxx吗，怎么会是sids[]:xx，option的值只有一个，不应该是数组的。楼主再仔细瞧瞧看哪里有错的。

Answer 2

是不是少了setter方法

Answer 3

有setter方法，但是报错了，我把报错张贴出来了，麻烦您看看

Answer 4

终于找到了服务器报错信息，之前都报空指针异常，现在报了这个错，我想才是根源，但是有点看不懂：

 2013-08-20 14:20:12,456 - com.opensymphony.xwork2.ognl.OgnlValueStack -327832 [http-bio-8080-exec-9] WARN  com.opensymphony.xwork2.ognl.OgnlValueStack  - Error setting expression 'sids[]' with value '[Ljava.lang.String;@2d7aea99' 
ognl.ExpressionSyntaxException: Malformed OGNL expression: sids[] [ognl.ParseException: Encountered " "]" "] "" at line 1, column 6.
Was expecting one of:
    ":" ...
    "not" ...
    "+" ...
    "-" ...
    "~" ...
    "!" ...
    "(" ...
    "true" ...
    "false" ...
    "null" ...
    "#this" ...
    "#root" ...
    "#" ...
    "[" ...
    "{" ...
    "@" ...
    "new" ...
    <IDENT> ...
    <DYNAMIC_SUBSCRIPT> ...
    "'" ...
    "`" ...
    """ ...
    <INT_LITERAL> ...
    <FLT_LITERAL> ...
    ]
at ognl.Ognl.parseExpression(Ognl.java:112)
at com.opensymphony.xwork2.ognl.OgnlUtil.compile(OgnlUtil.java:225)
at com.opensymphony.xwork2.ognl.OgnlUtil.setValue(OgnlUtil.java:209)
at com.opensymphony.xwork2.ognl.OgnlValueStack.trySetValue(OgnlValueStack.java:173)
at com.opensymphony.xwork2.ognl.OgnlValueStack.setValue(OgnlValueStack.java:160)
at com.opensymphony.xwork2.ognl.OgnlValueStack.setValue(OgnlValueStack.java:151)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.setParameters(ParametersInterceptor.java:288)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:199)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:142)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:166)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:190)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:485)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:931)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
Caused by: ognl.ParseException: Encountered " "]" "] "" at line 1, column 6.
Was expecting one of:
    ":" ...
    "not" ...
    "+" ...
    "-" ...
    "~" ...
    "!" ...
    "(" ...
    "true" ...
    "false" ...
    "null" ...
    "#this" ...
    "#root" ...
    "#" ...
    "[" ...
    "{" ...
    "@" ...
    "new" ...
    <IDENT> ...
    <DYNAMIC_SUBSCRIPT> ...
    "'" ...
    "`" ...
    """ ...
    <INT_LITERAL> ...
    <FLT_LITERAL> ...
    
at ognl.OgnlParser.generateParseException(OgnlParser.java:3172)
at ognl.OgnlParser.jj_consume_token(OgnlParser.java:3051)
at ognl.OgnlParser.unaryExpression(OgnlParser.java:1236)
at ognl.OgnlParser.multiplicativeExpression(OgnlParser.java:971)
at ognl.OgnlParser.additiveExpression(OgnlParser.java:894)
at ognl.OgnlParser.shiftExpression(OgnlParser.java:750)
at ognl.OgnlParser.relationalExpression(OgnlParser.java:508)
at ognl.OgnlParser.equalityExpression(OgnlParser.java:405)
at ognl.OgnlParser.andExpression(OgnlParser.java:352)
at ognl.OgnlParser.exclusiveOrExpression(OgnlParser.java:299)
at ognl.OgnlParser.inclusiveOrExpression(OgnlParser.java:246)
at ognl.OgnlParser.logicalAndExpression(OgnlParser.java:193)
at ognl.OgnlParser.logicalOrExpression(OgnlParser.java:140)
at ognl.OgnlParser.conditionalTestExpression(OgnlParser.java:101)
at ognl.OgnlParser.assignmentExpression(OgnlParser.java:64)
at ognl.OgnlParser.expression(OgnlParser.java:23)
at ognl.OgnlParser.index(OgnlParser.java:2336)
at ognl.OgnlParser.navigationChain(OgnlParser.java:1331)
at ognl.OgnlParser.unaryExpression(OgnlParser.java:1196)
at ognl.OgnlParser.multiplicativeExpression(OgnlParser.java:971)
at ognl.OgnlParser.additiveExpression(OgnlParser.java:894)
at ognl.OgnlParser.shiftExpression(OgnlParser.java:750)
at ognl.OgnlParser.relationalExpression(OgnlParser.java:508)
at ognl.OgnlParser.equalityExpression(OgnlParser.java:405)
at ognl.OgnlParser.andExpression(OgnlParser.java:352)
at ognl.OgnlParser.exclusiveOrExpression(OgnlParser.java:299)
at ognl.OgnlParser.inclusiveOrExpression(OgnlParser.java:246)
at ognl.OgnlParser.logicalAndExpression(OgnlParser.java:193)
at ognl.OgnlParser.logicalOrExpression(OgnlParser.java:140)
at ognl.OgnlParser.conditionalTestExpression(OgnlParser.java:101)
at ognl.OgnlParser.assignmentExpression(OgnlParser.java:64)
at ognl.OgnlParser.expression(OgnlParser.java:23)
at ognl.OgnlParser.topLevelExpression(OgnlParser.java:15)
at ognl.Ognl.parseExpression(Ognl.java:110)
... 59 more
/-- Encapsulated exception ------------
ognl.ParseException: Encountered " "]" "] "" at line 1, column 6.
Was expecting one of:
    ":" ...
    "not" ...
    "+" ...
    "-" ...
    "~" ...
    "!" ...
    "(" ...
    "true" ...
    "false" ...
    "null" ...
    "#this" ...
    "#root" ...
    "#" ...
    "[" ...
    "{" ...
    "@" ...
    "new" ...
    <IDENT> ...
    <DYNAMIC_SUBSCRIPT> ...
    "'" ...
    "`" ...
    """ ...
    <INT_LITERAL> ...
    <FLT_LITERAL> ...
    
at ognl.OgnlParser.generateParseException(OgnlParser.java:3172)
at ognl.OgnlParser.jj_consume_token(OgnlParser.java:3051)
at ognl.OgnlParser.unaryExpression(OgnlParser.java:1236)
at ognl.OgnlParser.multiplicativeExpression(OgnlParser.java:971)
at ognl.OgnlParser.additiveExpression(OgnlParser.java:894)
at ognl.OgnlParser.shiftExpression(OgnlParser.java:750)
at ognl.OgnlParser.relationalExpression(OgnlParser.java:508)
at ognl.OgnlParser.equalityExpression(OgnlParser.java:405)
at ognl.OgnlParser.andExpression(OgnlParser.java:352)
at ognl.OgnlParser.exclusiveOrExpression(OgnlParser.java:299)
at ognl.OgnlParser.inclusiveOrExpression(OgnlParser.java:246)
at ognl.OgnlParser.logicalAndExpression(OgnlParser.java:193)
at ognl.OgnlParser.logicalOrExpression(OgnlParser.java:140)
at ognl.OgnlParser.conditionalTestExpression(OgnlParser.java:101)
at ognl.OgnlParser.assignmentExpression(OgnlParser.java:64)
at ognl.OgnlParser.expression(OgnlParser.java:23)
at ognl.OgnlParser.index(OgnlParser.java:2336)
at ognl.OgnlParser.navigationChain(OgnlParser.java:1331)
at ognl.OgnlParser.unaryExpression(OgnlParser.java:1196)
at ognl.OgnlParser.multiplicativeExpression(OgnlParser.java:971)
at ognl.OgnlParser.additiveExpression(OgnlParser.java:894)
at ognl.OgnlParser.shiftExpression(OgnlParser.java:750)
at ognl.OgnlParser.relationalExpression(OgnlParser.java:508)
at ognl.OgnlParser.equalityExpression(OgnlParser.java:405)
at ognl.OgnlParser.andExpression(OgnlParser.java:352)
at ognl.OgnlParser.exclusiveOrExpression(OgnlParser.java:299)
at ognl.OgnlParser.inclusiveOrExpression(OgnlParser.java:246)
at ognl.OgnlParser.logicalAndExpression(OgnlParser.java:193)
at ognl.OgnlParser.logicalOrExpression(OgnlParser.java:140)
at ognl.OgnlParser.conditionalTestExpression(OgnlParser.java:101)
at ognl.OgnlParser.assignmentExpression(OgnlParser.java:64)
at ognl.OgnlParser.expression(OgnlParser.java:23)
at ognl.OgnlParser.topLevelExpression(OgnlParser.java:15)
at ognl.Ognl.parseExpression(Ognl.java:110)
at com.opensymphony.xwork2.ognl.OgnlUtil.compile(OgnlUtil.java:225)
at com.opensymphony.xwork2.ognl.OgnlUtil.setValue(OgnlUtil.java:209)
at com.opensymphony.xwork2.ognl.OgnlValueStack.trySetValue(OgnlValueStack.java:173)
at com.opensymphony.xwork2.ognl.OgnlValueStack.setValue(OgnlValueStack.java:160)
at com.opensymphony.xwork2.ognl.OgnlValueStack.setValue(OgnlValueStack.java:151)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.setParameters(ParametersInterceptor.java:288)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:199)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:207)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:142)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:166)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:190)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:248)
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:485)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:931)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

Answer 5

我放弃挣扎了，我本来想用sids以数组的形式提交参数，现在我干脆改成字符串算了，我再后面接了一个toString()方法，提交成功，只是数组提交我就真的不知道该怎么接收？有高手知道怎么接收的吗？

Answer 6

数组暂未实现,自己没事写代码时也没试成功

个人解决方法是name相同值不同后台为string[]

或者直接把数据toString在后台对想的set或者get方法中截取返回为一个数组。

Answer 7

我的做法就是toString，这是没办法的办法

Answer 8

传参不对吧。

没记错的话，给后台传数组时的参数应该是

sids:1

sids:2

sids:3

sids:4

sids:5

这样传，后台对应的sids[]就会自动赋值。如果你直接传sids[]:1什么的，就会出错了。

Answer 9

回复
我做过测试，用我说的那个方法可以正常的向后台传数组。用你说的这种我没试过。

Answer 10

参数是自动的，sids[]是数组的意思，我想也合理

Answer 11

回复
多个应该是通过,号来分割的啊。而且这个也不应该在浏览器体现出来的。所以这里传的有点问题。传到后台也是同样的获取方式的，request.getParameter，然后再进行相应的分割，这里问题不大的。再检查一下传到后台的值，可以调试一下request的parameter，看看究竟有没有那个参数。

Answer 12

回复
option的值的确有多个，因为我是多个option的值提交，自然是数组，可是数组在后台就接不住了，您知道是为什么吗？

Answer 13

为什么会是sids[]这样的格式，貌似名称有点问题啊？

楼主发一段select的代码出来，比较容易确定问题。

Answer 14

为什么会是sids[]这样的格式，貌似名称有点问题啊？

楼主发一段select的代码出来，比较容易确定问题。

Answer 15

名字应该没错

Answer 16

<select name="status" id="staSel"> <option value="AAAA">AAAA</option>..... 在action里取status的值,我这里能取到value..,如果多选,应该取的是string数组..

Answer 17

回复
我忘记说明了，不好意思，我是用jquery的ajax方式提交表单，参数都在ajax方法下定义的，并不是select，name的名字

Answer 18

根据select的name取的值,会不会action的name漏了..