For example, as in the `Image` model we have a `url` field, we can declare it to be an instance of Pydantic's `HttpUrl` instead of a `str`:

{* ../../docs_src/body_nested_models/tutorial005_py310.py hl[2,8] *}

/**
 * Verifies that subclasses from generated model classes are possible.
 */
class ExtendedPluginDescriptorTest {

    /**
     * A subclass of the generated class {@link PluginDescriptor} that adds an additional field.
     */
    static class ExtendedPluginDescriptor extends PluginDescriptor {

        private final String additionalField;

        ExtendedPluginDescriptor(Builder builder) {
            super(builder);

     * Creates a new EditForm instance.
     */
    public EditForm() {
        super();
    }

    /**
     * The unique identifier of the synonym dictionary entry being edited.
     * This is a required field for identifying which dictionary entry to update.
     */
    @Required
    @ValidateTypeFailure
    public Long id;

    /**
     * Returns a display-friendly identifier combining the dictionary ID and entry ID.

                    }
                });
    }

    private static StringBuilder appendJson(final String field, final Object value, final StringBuilder buf) {
        buf.append('"').append(StringEscapeUtils.escapeJson(field)).append('"').append(':');
        if (value == null) {
            buf.append("null");
        } else if (value instanceof LocalDateTime) {

{* ../../docs_src/query_param_models/tutorial001_an_py310.py hl[9:13,17] *}

**FastAPI** will **extract** the data for **each field** from the **query parameters** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the query parameters in the docs UI at `/docs`:

<div class="screenshot">

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.StringReader;
import java.lang.reflect.Field;
import java.nio.file.Path;
import java.util.Map;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.io.TempDir;
import org.mockito.MockedConstruction;

            addFieldToSource(sourceMap, "virtualHosts", virtualHosts);
        }
        return sourceMap;
    }

    protected void addFieldToSource(Map<String, Object> sourceMap, String field, Object value) {
        sourceMap.put(field, value);
    }

    // ===================================================================================
    //                                                                      Basic Override

   * restrictions</i>.
   */
  @Retention(RetentionPolicy.CLASS)
  @Target({ElementType.TYPE, ElementType.METHOD, ElementType.CONSTRUCTOR, ElementType.FIELD})
  @Documented
  @interface GwtIncompatible {
    String value();
  }

  private Partially() {}

   * remain in flight.
   */
  @get:Synchronized
  var maxRequests = 64
    set(maxRequests) {
      require(maxRequests >= 1) { "max < 1: $maxRequests" }
      synchronized(this) {
        field = maxRequests
      }
      promoteAndExecute()
    }

  /**
   * The maximum number of requests for each host to execute concurrently. This limits requests by

        int start = bufferIndex;
        int end = start + len;
        interfaces.clear();

        while (bufferIndex < end && (bufferIndex + 152) <= end) {
            // Read Next field to determine if there are more entries
            int next = SMBUtil.readInt4(buffer, bufferIndex);

            NetworkInterfaceInfo info = NetworkInterfaceInfo.decode(buffer, bufferIndex);
            if (info != null) {