ajax pass array and background receive

　Ajax passes {"items":arr}, where arr=[];

In the background String[] items=req.getParameterValues("items"); find that it cannot be received, print the parameter name

Enumeration<String> names = req.getParameterNames();
　　while (names.hasMoreElements()) {
　　String string = (String) names.nextElement();
　　System.out.println(string);
}

The print is "items[]", so it is changed to String[] items=req.getParameterValues("items[]"); for correct reception