回答編集履歴

内容修正

2020/05/09 22:14

投稿

shiketa

スコア3971

test CHANGED Viewed

@@ -48,21 +48,21 @@
     public Person clone() {
-      try {
+      try (
-        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
+          ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        final ObjectOutputStream oos = new ObjectOutputStream(baos);
+          ObjectOutputStream oos = new ObjectOutputStream(baos);) {
         oos.writeObject(this);
         oos.close();
+        try (
-        final ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+            ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
-        try (final ObjectInputStream ois = new ObjectInputStream(bais);) {
+            ObjectInputStream ois = new ObjectInputStream(bais);) {
           return (Person) ois.readObject();
@@ -189,3 +189,75 @@
 p2Person [name =name1, age=21, item=Item [name =アイテム1]]
 ```
+----
+外に切り出して、こんなの用意しとくのもよろしいかと。
+```java
+import java.io.*;
+public class Clones {
+  public static <A extends Serializable> A clone(final A source) {
+    if(source == null) return source;
+    try (
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ObjectOutputStream oos = new ObjectOutputStream(baos);) {
+      oos.writeObject(source);
+      oos.close();
+      try (
+          ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
+          ObjectInputStream ois = new ObjectInputStream(bais);) {
+        return (A) ois.readObject();
+      }
+    } catch (Exception e) {
+      throw new RuntimeException(e);
+    }
+  }
+}
+```
+```java
+  @Test
+  public void hoge2() throws Exception {
+    Item item = new Item("アイテム1");
+    Person p1 = new Person("name1", 21, item);
+    Person p2 = Clones.clone(p1);
+```