How to execute nested group mail merge with JSON in Word document using Java?

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Mail merge is a process of merging data from a data source into a Word template document. Syncfusion®Java Word library (Essential® DocIO) is used to generate reports like invoices, payrolls, letters, and more by performing a mail merge faster in a batch process without Microsoft Word or interop dependencies. Using this library, you can execute nested group mail merge with JSON in a Word document using Java.

Execute nested group mail merge with JSON in Word document using Java:

Create a new Java file and include the following namespaces.

JAVA

import com.syncfusion.docio.*;
import com.syncfusion.javahelper.system.collections.generic.DictionarySupport;
import com.syncfusion.javahelper.system.collections.generic.ListSupport;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;

Use the following code sample to perform nested mail merge using a JSON string in a Word document.

JAVA

// JSON string containing nested organizational data
String json = "{\"Organizations\":[{\"BranchName\":\"UK Office\",\"Address\":\"120 Hanover Sq.\",\"City\":\"London\",\"ZipCode\":\"WX1 6LT\",\"Country\":\"UK\",\"Departments\":[{\"DepartmentName\":\"Marketing\",\"Supervisor\":\"Nancy Davolio\",\"Employees\":[{\"EmployeeName\":\"Thomas Hardy\",\"EmployeeID\":\"1001\",\"JoinedDate\":\"05/27/1996\"},{\"EmployeeName\":\"Maria Anders\",\"EmployeeID\":\"1002\",\"JoinedDate\":\"04/10/1998\"}]},{\"DepartmentName\":\"Production\",\"Supervisor\":\"Andrew Fuller\",\"Employees\":[{\"EmployeeName\":\"Elizabeth Lincoln\",\"EmployeeID\":\"1003\",\"JoinedDate\":\"05/15/1996\"},{\"EmployeeName\":\"Antonio Moreno\",\"EmployeeID\":\"1004\",\"JoinedDate\":\"04/22/1996\"}]}]}]}";

// Convert JSON string into a JsonObject
JsonObject data = new Gson().fromJson(json, JsonObject.class);
// Convert JsonObject to DictionarySupport (required format for mail merge)
DictionarySupport<String, Object> result = getData(data);
// Load the Word document template
WordDocument document = new WordDocument("Template.docx");
// Extract the list of organizations for mail merge
MailMergeDataTable dataTable = new MailMergeDataTable("Organizations", (ListSupport<Object>) result.get("Organizations"));
// Perform nested mail merge with the data table
document.getMailMerge().executeNestedGroup(dataTable);
// Save the generated Word document
document.save("Result.docx", FormatType.Docx);
document.close();
System.out.println("Word document generated successfully.");

Use the following helper method to convert a JsonObject into DictionarySupport.

JAVA

public static DictionarySupport<String, Object> getData(JsonObject data) throws Exception {
   DictionarySupport<String, Object> map = new DictionarySupport<>(String.class, Object.class);

   for (String key : data.keySet()) {
       Object keyValue = null;
       if (data.get(key).isJsonArray()) {
           // Convert array to ListSupport
           keyValue = getData(data.getAsJsonArray(key));
       } else if (data.get(key).isJsonPrimitive()) {
           // Use primitive value directly
           keyValue = data.get(key).getAsString();
       }
       map.add(key, keyValue);
   }
   return map;
}

Use the following helper method to convert a JsonArray into ListSupport.

JAVA

// Converts a JsonArray into ListSupport recursively
public static ListSupport<Object> getData(JsonArray arr) throws Exception {
   ListSupport<Object> list = new ListSupport<>(Object.class);

   for (int i = 0; i < arr.size(); i++) {
       Object keyValue = null;
       if (arr.get(i).isJsonObject()) {
           // Recursively convert nested objects
           keyValue = getData(arr.get(i).getAsJsonObject());
       }
       list.add(keyValue);
   }
   return list;
}

You can download a complete working sample to execute nested group mail merge with JSON in a Word document from GitHub.

By executing the application, you will get the output Word document as follows.

You can refer to this link to learn how to run the Syncfusion® Java Word library (Essential® DocIO).

Take a moment to peruse the documentation. You can find basic Word document processing options along with features like mail merge, merge, and split documents.

How to execute nested group mail merge with JSON in Word document using Java?

Execute nested group mail merge with JSON in Word document using Java:

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