Java工具类05MapUtils常用操作

1.Map操作

1.1MapUtils

 <dependency>
      <groupId>org.apache.commons</groupId>
      <artifactId>commons-collections4</artifactId>
      <version>4.2</version>
    </dependency>

1.1.1判空

Boolean MapUtils.isEmpty(Map<K,V> map);
Boolean MapUtils.isNotEmpty(Map<K,V> map);

1.1.2取值

//获取键所对对应的值,以null安全的方式从Map获取String
String MapUtils.getString(Map(K,V) ,key ,"默认值" );
Boolean MapUtils.getBoolean(Map(K,V) ,key);
Integer MapUtils.getInteger(Map(K,V) ,key);

1.1.3设值

//结果--{蓝色=＃0000FF, 绿色=＃00FF00, 红色=＃FF0000}
Map colorMap = MapUtils.putAll(new HashMap(),new String [] {"红色","＃FF0000", "绿色","＃00FF00","蓝色","＃0000FF" });
//结果--{}
Map colorMap2 = null;
Map colorMap1 = MapUtils.emptyIfNull(colorMap2);