Question

这是我的jsp：

<form method='post' action='/controller'>
     <div >
         <input class="form-control" type="text" id="name-input-field" pattern="[A-Z][a-z]+([ -][A-Z][a-z]+)*" required >
     </div>                        
</form>

这是我的servlet：

protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
      req.getParameter("name-input-field");//appears null    
}

请帮我找到错误。

Answer 1

getParameter()方法包含name标记的input属性，而不是id属性。它返回value的{{1}}属性值。

将input添加到您的name="name-input-field"代码，以便在input中获取其值。

Answer 2

正如Yogesh所说，req.getParameter使用了名字，但你也必须知道：

想象一下这种情况：

您必须在html中禁用输入选项或任何可以使用的选项：

    import android.content.Context;
    import android.support.v7.widget.RecyclerView;
    import android.util.Log;
    import android.view.GestureDetector;
    import android.view.MotionEvent;
    import android.view.View;

public class RecyclerTouchListener implements RecyclerView.OnItemTouchListener {

private GestureDetector gestureDetector;
private ClickListener clickListener;

public RecyclerTouchListener(Context context, final RecyclerView recyclerView, final ClickListener clickListener) {
    Log.d("Slider", "constructer");
    this.clickListener = clickListener;
    gestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            return true;
        }

        @Override
        public void onLongPress(MotionEvent e) {
            View child = recyclerView.findChildViewUnder(e.getX(), e.getY());
            if (child != null && clickListener != null) {

                clickListener.onLongClick(child, recyclerView.getChildPosition(child));
            }

        }
    });
}

@Override
public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {

    View child = rv.findChildViewUnder(e.getX(), e.getY());
    if (child != null && clickListener != null && gestureDetector.onTouchEvent(e)) {

        clickListener.onClick(child, rv.getChildPosition(child));
    }
    Log.d("Slider", "onInterceptTouchEvent" + gestureDetector.onTouchEvent(e));
    return false;
}

@Override
public void onTouchEvent(RecyclerView rv, MotionEvent e) {
    Log.d("Slider", "onTouchEvent" + e);
}

@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

}

public static interface ClickListener {
    public void onClick(View view, int position);

    public void onLongClick(View view, int position);
}
}

Well Sr你会得到一个null因为你的请求中没有发送禁用输入;）所以要小心

请求参数在servlet中显示为null

2 个答案: