反射扩容对象数组

JeffLi1993 · JeffLi1993 · commit e3fee6dabcb8 · 2015-11-09T11:28:19.000+08:00
diff --git a/src/org/javacore/reflection/ArrayCopy.java b/src/org/javacore/reflection/ArrayCopy.java
@@ -0,0 +1,51 @@
+package org.javacore.reflection;
+
+import java.lang.reflect.Array;
+import java.util.Arrays;
+
+/*
+ * Copyright [2015] [Jeff Lee]
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * @author Jeff Lee
+ * @since 2015-11-9 10:45:19
+ * 反射扩容对象数组
+ */
+public class ArrayCopy {
+    public static void main(String[] args) {
+        int[] a = {1,2,3};
+        a = (int[]) goodCopyOf(a,10);
+        System.out.println(Arrays.toString(a));
+
+        String[] str = {"a","b","c"};
+        str = (String[]) goodCopyOf(str,10);
+        System.out.println(Arrays.toString(str));
+    }
+
+    public static Object goodCopyOf(Object a,int newLength){
+        // 获取Class对象
+        Class cl = a.getClass();
+        // 如果不是数组对象，则返回null;
+        if (!cl.isArray()) return null;
+        // 获取数组组件对象
+        Class componentType = cl.getComponentType();
+        int length = Array.getLength(a);
+        Object newArray = Array.newInstance(componentType,newLength);
+        // 复制数组
+        System.arraycopy(a,0,newArray,0,Math.min(length,newLength));
+        return newArray;
+    }
+}
