深克隆与浅克隆

src/main/java/top/fjy8018/designpattern/pattern/creational/prototype/clone/CMailAfter.java

@@ -0,0 +1,64 @@
+package top.fjy8018.designpattern.pattern.creational.prototype.clone;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
+
+import java.util.Date;
+
+/**
+ * 原型模式：使用原型实例指定待创建对象的类型，并且通过<strong>复制</strong>这个原型来创建新的对象
+ * 适用于初始化对象复杂的场景
+ * <p>
+ * 邮件——深克隆实现
+ *
+ * @author F嘉阳
+ * @date 2018-09-25 20:39
+ */
+@Slf4j
+@Getter
+@Setter
+public class CMailAfter implements Cloneable {
+
+    private String name;
+    /**
+     * String类型本身是不可变，不需要重新实现深克隆
+     */
+    private Date date;
+    private String content;
+
+    public CMailAfter() throws InterruptedException {
+        // 模拟调用构造器需要复杂过程
+        Thread.sleep(100);
+        log.debug(this.getClass().getSimpleName() + "构造器调用");
+    }
+
+    /**
+     * 带上父类toString方法查看是否为同一个对象
+     *
+     * @return
+     */
+    @Override
+    public String toString() {
+        return "CMailAfter{" +
+                "name='" + name + '\'' +
+                ", date=" + date +
+                ", content='" + content + '\'' +
+                '}';
+    }
+
+    /**
+     * 调用克隆函数不需要调用构造器以此加快实例化速度
+     * 通过调用每个属性的克隆方法实现深克隆
+     *
+     * @return
+     * @throws CloneNotSupportedException
+     */
+    @Override
+    public Object clone() throws CloneNotSupportedException {
+        CMailAfter mail = (CMailAfter) super.clone();
+        // 单独对Date进行克隆
+        mail.date = (Date) date.clone();
+        return mail;
+    }
+}

src/main/java/top/fjy8018/designpattern/pattern/creational/prototype/clone/CMailBefore.java

@@ -0,0 +1,58 @@
+package top.fjy8018.designpattern.pattern.creational.prototype.clone;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.extern.slf4j.Slf4j;
+
+import java.util.Date;
+
+/**
+ * 原型模式：使用原型实例指定待创建对象的类型，并且通过<strong>复制</strong>这个原型来创建新的对象
+ * 适用于初始化对象复杂的场景
+ * <p>
+ * 邮件
+ *
+ * @author F嘉阳
+ * @date 2018-09-25 20:39
+ */
+@Slf4j
+@Getter
+@Setter
+public class CMailBefore implements Cloneable {
+
+    private String name;
+    private Date date;
+    private String content;
+
+    public CMailBefore() throws InterruptedException {
+        // 模拟调用构造器需要复杂过程
+        Thread.sleep(100);
+        log.debug(this.getClass().getSimpleName() + "构造器调用");
+    }
+
+    /**
+     * 带上父类toString方法查看是否为同一个对象
+     *
+     * @return
+     */
+    @Override
+    public String toString() {
+        return "CMailBefore{" +
+                "name='" + name + '\'' +
+                ", date=" + date +
+                ", content='" + content + '\'' +
+                '}';
+    }
+
+    /**
+     * 调用克隆函数不需要调用构造器以此加快实例化速度
+     * 通过调用每个属性的克隆方法实现深克隆
+     *
+     * @return
+     * @throws CloneNotSupportedException
+     */
+    @Override
+    public Object clone() throws CloneNotSupportedException {
+        return super.clone();
+    }
+}

src/test/java/top/fjy8018/designpattern/pattern/creational/prototype/before/BMailTest.java

@@ -6,6 +6,10 @@ import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import top.fjy8018.designpattern.pattern.creational.prototype.after.AMail;
 import top.fjy8018.designpattern.pattern.creational.prototype.after.AMailUtil;
+import top.fjy8018.designpattern.pattern.creational.prototype.clone.CMailAfter;
+import top.fjy8018.designpattern.pattern.creational.prototype.clone.CMailBefore;
+
+import java.util.Date;
 
 @Slf4j
 class BMailTest {
@@ -66,6 +70,73 @@ class BMailTest {
         }
         // 本意希望在发送完所有邮件后保存开始的正文
         AMailUtil.saveOriginMail(mail);
+    }
+
+    /**
+     * 由于String不可变性保证其稳定性，而Date没有单独进行属性克隆导致
+     * <p>
+     * output
+     * ===
+     * CMailBefore构造器调用
+     * 15d0c81b CMailBefore{name='原始', date=Thu Jan 01 08:00:00 CST 1970, content='原始正文'}
+     * 4b1c1ea0 CMailBefore{name='原始', date=Thu Jan 01 08:00:00 CST 1970, content='原始正文'}
+     * ===============
+     * 15d0c81b CMailBefore{name='更新', date=Sun Sep 09 09:46:39 CST 2001, content='原始正文'}
+     * 4b1c1ea0 CMailBefore{name='原始', date=Sun Sep 09 09:46:39 CST 2001, content='原始正文'}
+     * 耗时109ms
+     * ===
+     *
+     * @throws Exception
+     */
+    @Test
+    void cloneTestBefore() throws Exception {
+        CMailBefore mail1 = new CMailBefore();
+        mail1.setName("原始");
+        mail1.setContent("原始正文");
+        mail1.setDate(new Date(0L));
+        CMailBefore mail2 = (CMailBefore) mail1.clone();
+        log.debug(Integer.toHexString(mail1.hashCode()) + " " + mail1);
+        log.debug(Integer.toHexString(mail2.hashCode()) + " " + mail2);
+
+        // 改变属性值
+        mail1.setName("更新");
+        mail1.getDate().setTime(999999999999L);
+        // 注意，若使用mail1.setDate(new Date());方式赋值不会导致两者同时变更
+        log.debug("===============");
+        log.debug(Integer.toHexString(mail1.hashCode()) + " " + mail1);
+        log.debug(Integer.toHexString(mail2.hashCode()) + " " + mail2);
 
     }
+
+    /**
+     * output
+     * ===
+     * CMailAfter构造器调用
+     * 15d0c81b CMailAfter{name='原始', date=Thu Jan 01 08:00:00 CST 1970, content='原始正文'}
+     * 4b1c1ea0 CMailAfter{name='原始', date=Thu Jan 01 08:00:00 CST 1970, content='原始正文'}
+     * ===============
+     * 15d0c81b CMailAfter{name='更新', date=Sun Sep 09 09:46:39 CST 2001, content='原始正文'}
+     * 4b1c1ea0 CMailAfter{name='原始', date=Thu Jan 01 08:00:00 CST 1970, content='原始正文'}
+     * 耗时110ms
+     * ===
+     *
+     * @throws Exception
+     */
+    @Test
+    void cloneTestAfter() throws Exception {
+        CMailAfter mail1 = new CMailAfter();
+        mail1.setName("原始");
+        mail1.setContent("原始正文");
+        mail1.setDate(new Date(0L));
+        CMailAfter mail2 = (CMailAfter) mail1.clone();
+        log.debug(Integer.toHexString(mail1.hashCode()) + " " + mail1);
+        log.debug(Integer.toHexString(mail2.hashCode()) + " " + mail2);
+
+        // 改变属性值
+        mail1.setName("更新");
+        mail1.getDate().setTime(999999999999L);
+        log.debug("===============");
+        log.debug(Integer.toHexString(mail1.hashCode()) + " " + mail1);
+        log.debug(Integer.toHexString(mail2.hashCode()) + " " + mail2);
+    }
 }