数组溢出错误java.lang.IndexOutOfBoundsException，在线等

[暖暖猫]

List lista=districtService.getc(district_id);
		StringBuffer s = new StringBuffer();
		for(int i=0;i<lista.size();i++){			
			s.append(lista.get(i)+"-");
		}
		String[] aString=s.toString().split("-");	
		for(int a=0;a<aString.length;a++){
		Pattern pattern = Pattern.compile("=(.+)\\}");
        Matcher matcher = pattern.matcher(aString[a]);
        System.out.println(aString[a]);
        while(matcher.find()) {
            out.print(matcher.group(a)+",");
        }
        }

上面是代码片段

No group 2
	at java.util.regex.Matcher.group(Unknown Source)
	at com.gpcsoft.srplatform.auth.controller.ExerciseController.eUserAjaxa(ExerciseController.java:69)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
	at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:427)
	at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:415)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:788)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:717)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:549)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
	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:174)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:879)
	at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
	at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
	at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
	at java.lang.Thread.run(Unknown Source)

下面是报错的，只是我不明白为什么会数组溢出

[暖暖猫]

·····把group(a)改成group(1)就可以了，我很无奈，还是要看api，group这个函数都没用过

[frankgoahead]

当然会溢出了， s.append(lista.get(i)+"-");
最后一个字符串后面加上了“-”

[wl_ldy]

那说明aString.length=2
group(0),group(1)存在group(2)不存在吧...

[暖暖猫]

[Quote=引用 2 楼 frankgoahead 的回复:]

当然会溢出了， s.append(lista.get(i)+"-");
最后一个字符串后面加上了“-”
[/Quote]
我自己解决了···，报的错，不是那个“-”，而是另一个，和这个无关的
你说的那里，是要把list专程StringBuffer ，然后在截取StringBuffer中的数据，得到我用的数据

[暖暖猫]

[Quote=引用 3 楼 wl_ldy 的回复:]

那说明aString.length=2
group(0),group(1)存在group(2)不存在吧...
[/Quote]

```我只要汉字，所以，截取的时候，把group（1）就可以用了，我很无语，o(︶︿︶)o 唉

[wangxx777]

List<String> lista = new ArrayList<String>();
lista.add("a");
lista.add("b");
lista.add("c");
lista.add("d");
StringBuffer s = new StringBuffer();
for (int i = 0; i < lista.size(); i++) {
s.append(lista.get(i) + "-");
System.out.println(s.toString());
}
String[] aString = s.toString().split("-");
for (int a = 0; a < aString.length; a++) {
Pattern pattern = Pattern.compile("=(.+)\\}");
Matcher matcher = pattern.matcher(aString[a]);
System.out.println(aString[a]);
while (matcher.find()) {
System.out.println(matcher.group(a) + ",");
}
}
会不会是你的list数据有问题啊，我模拟了一下，程序没有问题啊！

[暖暖猫]

[Quote=引用 6 楼 wangxx777 的回复:]

List<String> lista = new ArrayList<String>();
lista.add("a");
lista.add("b");
lista.add("c");
lista.add("d");
StringBuffer s = new StringBuffer();
for (int i = 0; i < lista.size(); i++) {
s.ap……
[/Quote]
······解决了，不是数据问题，是截取问题，matcher.group(a) 把a改成1，就可以了，因为我要界面用，所以用的out.print()
现在没问题了