argument type mismatch 参数类型不匹配的问题

Question

public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");

        try {
            User u = new User();
            System.out.println("封装数据前："+u);
            //获取表单数据
            Map<String,String[]> map = request.getParameterMap();

            for (Map.Entry<String, String[]> m : map.entrySet()) {
                String name = m.getKey();
                String[] value = m.getValue();

                //创建一属性描述器
                PropertyDescriptor pd = new PropertyDescriptor(name,User.class);
                //得到setter属性
                Method setter = pd.getWriteMethod();

                if(value.length==1){
                    setter.invoke(u, value[0]);//给一个值的变量赋值
                }else{
                    setter.invoke(u, (Object)value);//相当于给复选框赋值
                }
            }
            System.out.println("封装数据后："+u);
        } catch (Exception e) {
            e.printStackTrace();
        }
}

报错：
封装数据前:User [userName=null, pwd=null, sex=null, hobby=null, city=null]
java.lang.IllegalArgumentException: argument type mismatch
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at Demon.servlet.servletDemo3.doGet(servletDemo3.java:39)
at Demon.servlet.servletDemo3.doPost(servletDemo3.java:80)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)

at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)

at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)

at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:315)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)

这个是哪里错了

Answer 1

  肯定有个类型不匹配，你的请求参数都是string类型的，但是你的User类的属性并不都是string类型的，直接调用设置就可能报这个异常了。你的sex属性是什么类型呢？