如何从会话作为JsonNode访问| $ {user.get（）}

Question

I'm creating a simple session object (JsonNode)

JsonNode me = mapper.readValue(result, JsonNode.class);

HttpSession session = request.getSession(true);
session.setAttribute("user", me);

The trying to access it like this.

${user} // works print {"id":8,"name":"jones"..}
${user.id} // trows Error "Property 'id' not found on type org.codehaus.jackson.node.ObjectNode"
${user.get(0)} // nothing printed out.
${user.size()} // return 4, id,name,username,token

How do would i re factor my code to fix the problem, or even the selector?

Answer 1

The version @mindas suggested should work, unless you are using Tomcat 7. Seems that Tomcat 7 has a bug when calling overloaded methods with JSP EL ( see an issue here ). Are you using Tomcat 7?

The ${user.get(0)} isn't printing anything because that method is for accessing the value of the specified element of an array node. Yours is not an array node and if you use ${user.get("id")} you should get the value for the id field, unless you are on Tomcat 7 where you will get some error like Cannot convert id of type class java.lang.String to int .

You could try a quick and dirty test with ${user.findValue("id")} and see if you at least get some result, but if you don't mind me saying, I think it will be better if you would not expose a raw object like JsonNode to the JSP but some sort of User POJO with getters and setters for id , name , username and token instead. You could then use ${user.id} in the JSP and you will have no issue with Tomcat.