1、 准备两个待合并的映射表，示例中通过新建获取，实际应用时应从数据库或其它数据源读取所需数据。 2、 调用putAll方法合并map时，需先判断对象是否为null。为避免map01为null导致无法合并map02，应新建一个map实例来确保操作顺利执行。

package dustin.examples; /** * Enum representing select western states in the United Sates. */ public enum States { ARIZONA("Arizona"), CALIFORNIA("California ...

Community driven content discussing all aspects of software development from DevOps to design patterns. The Java enum, introduced in Java 5, will map to the underlying database without any ...

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