How to use a Map as if it was just a simple Map

Question

I'm trying to work on jdbctemplate. Reading this, I've reach part 2, which uses the code List<Map> rows = getJdbcTemplate().queryForList(sql);. When I try to implement it in my code, eclipse forces me to use Map<String,Object> instead of simply Map as in the tutorial.

I'm new to java so I don't know how to access my database columns when it's Map<String,Object>.

How do we do that ?

Is the code below okay ?

List<Map<String,Object>> rows = getJdbcTemplate().queryForList(sql);
    for (Map<String,Object> row : rows) {
        Customer customer = new Customer();
        customer.setCustId((Long)(row.get("CUST_ID")));
        customer.setName((String)row.get("NAME"));
        customer.setAge((Integer)row.get("AGE"));
        customers.add(customer);
    }
    return customers;

Update

Below is the error I get with this code

type Exception report

message Request processing failed; nested exception is java.lang.ClassCastException: java.math.BigDecimal cannot be cast to java.lang.String

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.ClassCastException: java.math.BigDecimal cannot be cast to java.lang.String org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:982) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) javax.servlet.http.HttpServlet.service(HttpServlet.java:622) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.lang.ClassCastException: java.math.BigDecimal cannot be cast to java.lang.String com.projet.testjdbc2.ArticleDAO.listerLesArticles(ArticleDAO.java:20) com.projet.testjdbc.HomeController.home2(HomeController.java:78) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) java.lang.reflect.Method.invoke(Unknown Source) org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97) org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) javax.servlet.http.HttpServlet.service(HttpServlet.java:622) org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) javax.servlet.http.HttpServlet.service(HttpServlet.java:729) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

Because that is better. That tutorial uses raw types. Long outdated bad practice. — GhostCat, May 20 '17 at 11:01
@JavaGuynextdoor Nope it does not. It says something like `BigDecimal` to `String` conversion error somewhere....as if I as using a number as a string or the inverse...That is what is happening — Bloomberg58, May 20 '17 at 21:51
@Bloomberg58 Please write here the error message you are getting. — Ossin Java guy, May 21 '17 at 09:30
@JavaGuynextdoor Please see yhe update in my OP with the information you asked about — Bloomberg58, May 21 '17 at 22:26
'Says something like ...' is not an acceptable problem description, anywhere, let alone here. You wouldn't accept that from a customer. Don't try it here. — user207421, May 22 '17 at 00:09

score 0 · Answer 1 · answered May 21 '17 at 22:56

0

Very hard to believe that any of these fields is a BigDecimal to begin with, but whichever it is, don't cast it to String: cast it to BigDecimal. Obviously.

It doesn't have anything to do with Map versus Map<String, Object>.

answered May 21 '17 at 22:56

user207421

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How to use a Map as if it was just a simple Map

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