本应该控制台输出
product0:null
product1:(这里是product的内容)
System.out.println("product0:"+product);
JSONObject parseObject = JSONObject.parseObject(productStr);
product = JSONObject.toJavaObject(parseObject, Product.class);
System.out.println("product1:"+product);
```Product product = null;
```try {
String productStr = String.valueOf(request.getParameter("productStr"));
System.out.println("productstr------>"+productStr);
//System.out.println("productstr:----------->"+productStr);
// 尝试获取前端传过来的表单string流并将其转换成Product实体类
System.out.println("product0:"+product);
JSONObject parseObject = JSONObject.parseObject(productStr);
//product = mapper.readValue(productStr, Product.class);
product = JSONObject.toJavaObject(parseObject, Product.class);
System.out.println("product1:"+product);
}