[Developer] #618 add structured data browser

src/main/java/com/cloudhandson/vpdbackoffice/web/StructuredDataController.java

@@ -0,0 +1,34 @@
+package com.cloudhandson.vpdbackoffice.web;
+
+import com.cloudhandson.vpdbackoffice.service.AppException;
+import com.cloudhandson.vpdbackoffice.service.StructuredDataService;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+@Controller
+public class StructuredDataController {
+
+  private final StructuredDataService structuredDataService;
+
+  public StructuredDataController(StructuredDataService structuredDataService) {
+    this.structuredDataService = structuredDataService;
+  }
+
+  @GetMapping("/structured-data")
+  public String structuredData(
+      @RequestParam(required = false) String table,
+      Model model
+  ) {
+    String selectedKey = table == null || table.isBlank() ? structuredDataService.defaultKey() : table;
+    model.addAttribute("tables", structuredDataService.tables());
+    model.addAttribute("selectedKey", selectedKey);
+    try {
+      model.addAttribute("preview", structuredDataService.preview(selectedKey));
+    } catch (AppException exception) {
+      model.addAttribute("errorMessage", exception.getMessage());
+    }
+    return "structured-data";
+  }
+}