Hereby, I just provide a more convenient way to access and process HTTP data. Now I illustrate some use cases in esProc, an innovative data processing language.
In this example, a servlet provides outward query of employee information in json format. Servlet accesses employee table in the database and saves employee information as follows:
EID NAME SURNAME GENDER STATE BIRTHDAY HIREDATE DEPT SALARY
1 Rebecca Moore F California 1974-11-20 2005-03-11 R&D 7000
2 Ashley Wilson F New York 1980-07-19 2008-03-16 Finance 11000
3 Rachel Johnson F New Mexico1970-12-17 2010-12-01 Sales 9000
4 Emily Smith F Texas 1985-03-07 2006-08-15 HR 7000
5 Ashley Smith F Texas 1975-05-13 2004-07-30 R&D 16000
6 Matthew Johnson M California 1984-07-07 2005-07-07 Sales 11000
7 Alexis Smith F Illinois 1972-08-16 2002-08-16 Sales 9000
8 Megan Wilson F California 1979-04-19 1984-04-19 Marketing 11000
9 Victoria Davis F Texas 1983-12-07 2009-12-07 HR 3000
…
doGet function of servlet receives employee id strings of json format, queries corresponding employee information through the database and generates employee information list in json format and then returns it. Process of reading the database and generating employee information is omitted in the following code:
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
// TODO Auto-generated method stub
String inputString=(String) req.getParameter("input");
//inputString input value is："[{EID:8},{EID:32},{EID:44}]";
if (inputString==null) inputString="";
String outputString ="";
{...}//code for querying the database through inputString and generating outputSring is omitted here
// the generated outputString
//"[{EID:8,NAME:"Megan",SURNAME:"Wilson",GENDER:"F",STATE:\...";
resp.getOutputStream().println(outputString);
resp.setContentType("text/json; charset=GBK");
}
The following code can be used for esProc to access this http servlet:
A1： Define the input parameter to be submitted to servlet, i.e. the employee id list in json format.
A2： Define httpfile objects, URL is http://localhost:8080/demo/testServlet?input=[{EID:8},{EID:32},{EID:44}].
A3：Import A2, the result returned by httpfile objects.
A4：Parse by rows the json format information of each employee, and create a sequence.
A5：Compute on the table sequence in A4 and combine SURNAME and NAME into FULLNAME.
A6：Export results of A5 to a text file.