如何使用Java将Docusign中的占位符字段的拖放功能集成到我的web应用程序中？

<dependency>
    <groupId>com.docusign</groupId>
    <artifactId>docusign-esign-java</artifactId>
    <version>2.0.0</version>
</dependency>

ApiClient apiClient = new ApiClient();
apiClient.setBasePath("https://demo.docusign.net/restapi");
apiClient.addDefaultHeader("Authorization", "Bearer YOUR_API_KEY");

EnvelopeDefinition envelopeDefinition = new EnvelopeDefinition();
envelopeDefinition.setEmailSubject("请签署此文档");
envelopeDefinition.setStatus("sent");

Document document = new Document();
document.setDocumentBase64(Base64.getEncoder().encodeToString(fileBytes));
document.setName("文档名称");
document.setFileExtension("pdf");
document.setDocumentId("1");

envelopeDefinition.setDocuments(Arrays.asList(document));

Tabs tabs = new Tabs();
Text textTab = new Text();
textTab.setDocumentId("1");
textTab.setPageNumber("1");
textTab.setXPosition("100");
textTab.setYPosition("100");
textTab.setFontSize("12");
textTab.setTabLabel("占位符字段");

tabs.setTextTabs(Arrays.asList(textTab));
envelopeDefinition.setTabs(tabs);

EnvelopesApi envelopesApi = new EnvelopesApi(apiClient);
EnvelopeSummary envelopeSummary = envelopesApi.createEnvelope("YOUR_ACCOUNT_ID", envelopeDefinition);