[EDIT] CAMBIOS DE CARGO PARA REPARAR LA CONSULTA QUE DEMORABA MUCHO

src/main/java/com/mycompany/moduloseguridad/dao/UsuarioDAO.java

@@ -51,4 +51,6 @@ public interface UsuarioDAO {
 	public int validarAsignacion(int codigo) throws Exception;
 
 	public JSONObject listarUsuarioManual(JSONObject datos) throws Exception;
+
+	JSONObject listarCargoUsuario() throws Exception;
 }
\ No newline at end of file

src/main/java/com/mycompany/moduloseguridad/mysqldao/UsuarioMYSQLDAO.java

@@ -640,4 +640,54 @@ public class UsuarioMYSQLDAO implements UsuarioDAO {
 		}
 		return new JSONObject(response);
 	}
+
+	@Override
+	public JSONObject listarCargoUsuario(){
+		JSONObject jreturn = new JSONObject();
+		JSONArray lista = new JSONArray();
+		Connection con = null;
+		PreparedStatement pst = null;
+		ResultSet rSet = null;
+		String sql = "";
+		try {
+			con = MySQLDAOFactory.getConnectionSQL(GeneralVariables.nameDB);
+			sql = " select\n" +
+					"    descargo as nom_car\n" +
+					"    from seguridad.usuario\n" +
+					"    inner join nuevo.personal on usuario.cod_trabajador = personal.tmp_id\n" +
+					"   inner join nuevo.cargo on personal.codcargo = cargo.codcargo\n" +
+					"group by descargo\n" +
+					"order by descargo;";
+			pst = con.prepareStatement(sql);
+			rSet = pst.executeQuery();
+			while (rSet.next()) {
+				JSONObject obj = new JSONObject();
+				obj.put("nom_car", rSet.getString(1));
+				lista.put(obj);
+			}
+			jreturn.put("data",lista);
+			jreturn.put("status",true);
+		} catch (Exception e) {
+			e.printStackTrace();
+			jreturn.put("data",new JSONArray());
+			jreturn.put("status",false);
+		} finally {
+			try {
+				if (rSet != null) {
+					rSet.close();
+				}
+				if (pst != null) {
+					pst.close();
+				}
+				if (con != null) {
+					con.close();
+				}
+			} catch (Exception e) {
+				e.printStackTrace();
+				jreturn.put("data",lista);
+				jreturn.put("status",true);
+			}
+		}
+		return jreturn;
+	}
 }
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src/main/java/com/mycompany/moduloseguridad/services/UsuarioService.java

@@ -208,4 +208,14 @@ public class UsuarioService {
 		}
 		return obj;
 	}
+
+	public JSONObject listarCargoUsuario() {
+		JSONObject obj = null;
+		try {
+			obj = dao.listarCargoUsuario();
+		} catch (Exception e) {
+			e.printStackTrace();
+		}
+		return obj;
+	}
 }
\ No newline at end of file

src/main/java/com/mycompany/moduloseguridad/servlets/UsuarioServlet.java

@@ -424,18 +424,7 @@ public class UsuarioServlet extends HttpServlet {
 		response.setContentType("application/json");
 		PrintWriter out = response.getWriter();
 		UsuarioService srv = new UsuarioService();
-		JSONObject json = srv.listarUsuarioManual(new JSONObject());
-		ArrayList<String> cargos = new ArrayList<>();
-		JSONArray lista = json.getJSONArray("results");
-		for (int i = 0; i < lista.length(); i++) {
-			JSONObject obj = lista.getJSONObject(i);
-			JSONObject prs = listarPersonalPorCodigo(obj.getString("codigoTrabajador"));
-			if(!prs.isNull("nom_car")){
-			if (!cargos.contains(prs.getString("nom_car"))) {
-				cargos.add(prs.getString("nom_car"));
-			}
-			}
-		}
-		out.print(new JSONArray(cargos));
+		JSONObject json = srv.listarCargoUsuario();
+		out.print(new JSONArray(json.getJSONArray("data")));
 	}
 }
\ No newline at end of file

src/main/webapp/js/pages/usuario.js

@@ -80,7 +80,7 @@ cargarCargos = () => {
     listarCargosDeUsuario()
         .then(data => {
             let print = "<option value=''>TODOS</option>"
-            print += data.map(obj => `<option value="${obj}">${obj}</option>`)
+            print += data.map(obj => `<option value="${obj.nom_car}">${obj.nom_car}</option>`)
             document.getElementById('cboCargos').innerHTML = print
         })
         .then(() => {