# JSON互換エンコーダ

データ型（Pydanticモデルのような）をJSONと互換性のあるもの（`dict`や`list`など）に変更する必要がある場合があります。

例えば、データベースに保存する必要がある場合です。

そのために、**FastAPI** は`jsonable_encoder()`関数を提供しています。

## `jsonable_encoder`の使用

JSON互換のデータのみを受信するデータベース`fase_db`があるとしましょう。

例えば、`datetime`オブジェクトはJSONと互換性がないので、このデーターベースには受け取られません。

そのため、`datetime`オブジェクトは<a href="https://en.wikipedia.org/wiki/ISO_8601" class="external-link" target="_blank">ISO形式</a>のデータを含む`str`に変換されなければなりません。

  val id = (matcher.groupValues[1] + matcher.groupValues[2]).decodeHex()
  return SuiteId(id, matcher.groupValues[3])
}

class IanaSuites(
  val name: String,
  val suites: List<SuiteId>,
) {
  fun fromJavaName(javaName: String): SuiteId {
    return suites.firstOrNull {
      it.name == javaName || it.name == "TLS_${javaName.drop(4)}"

/** Unit tests for {@link Service} */
public class ServiceTest extends TestCase {

  /** Assert on the comparison ordering of the State enum since we guarantee it. */
  public void testStateOrdering() {
    // List every valid (direct) state transition.
    assertLessThan(NEW, STARTING);
    assertLessThan(NEW, TERMINATED);

    assertLessThan(STARTING, RUNNING);
    assertLessThan(STARTING, STOPPING);

	if reducedErr != nil {
		return FileInfo{}, reducedErr
	}

	// List all the file commit ids from parts metadata.
	modTimes := listObjectModtimes(partsMetadata, errs)

	// Count all latest updated FileInfo values
	var count int
	var latestFileInfo FileInfo

	// Reduce list of UUIDs to a single common value - i.e. the last updated Time
	modTime := commonTime(modTimes, expectedRQuorum)

              <!-- was only a workaround for Plexus Container, hopefully never used by anyone else -->
              <exclude>org.apache.maven.plugin.DefaultBuildPluginManager#setMojoExecutionListeners(java.util.List)</exclude>

	}
	t.Logf("Created temporary dir: %v", tempDir)
	return tempDir
}

func ls(dir string, t *testing.T) []string {
	files, err := os.ReadDir(dir)
	t.Helper()
	if err != nil {
		t.Fatalf("Failed to list files, err: %v", err)
	}
	return slices.Map(files, func(e os.DirEntry) string {
		return e.Name()
	})
}

func cp(src, dest string, t *testing.T) {
	t.Helper()
	data, err := os.ReadFile(src)
	if err != nil {

            new ConcurrentHashMultiset<>(new ConcurrentSkipListMap<String, AtomicInteger>());
        Collections.addAll(multiset, elements);
        return multiset;
      }

      @Override
      public List<String> order(List<String> insertionOrder) {
        return Ordering.natural().sortedCopy(insertionOrder);
      }
    };
  }

  private static final String KEY = "puppies";

   * this {@code TopKSelector}.
   *
   * <p>The returned list is an unmodifiable copy and will not be affected by further changes to
   * this {@code TopKSelector}. This method returns in O(k log k) time.
   */
  public List<T> topK() {
    @SuppressWarnings("nullness") // safe because we pass sort() a range that contains real Ts
    T[] castBuffer = (T[]) buffer;

import com.google.common.collect.Lists;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multiset;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A series of tests that support asserting that collections cannot be modified, either through

import com.google.common.testing.TestLogHandler;
import com.google.j2objc.annotations.J2ObjCIncompatible;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;