如何替换列表<;地图>;地图键';java中的s值
我想在这里重新计算所有迭代的时间值如何替换列表<;地图>;地图键';java中的s值,java,list,dictionary,collections,Java,List,Dictionary,Collections,我想在这里重新计算所有迭代的时间值 List<Map<String,Object>> mapList=new ArrayList<Map<String,Object>>(); Map myMap1=new HashMap(); myMap1.put("name", "jai"); myMap1.put("time", Instant.now()); mapList.add(myMap1);
List<Map<String,Object>> mapList=new ArrayList<Map<String,Object>>();
Map myMap1=new HashMap();
myMap1.put("name", "jai");
myMap1.put("time", Instant.now());
mapList.add(myMap1);
Map myMap2=new HashMap();
myMap2.put("name", "kishan");
myMap2.put("time", Instant.now());
List-mapList=new-ArrayList();
Map myMap1=新的HashMap();
myMap1.put(“名称”、“jai”);
myMap1.put(“time”,Instant.now());
mapList.add(myMap1);
Map myMap2=新的HashMap();
myMap2.put(“名称”、“基山”);
myMap2.put(“time”,Instant.now());
使用删除(“时间”)
返回旧值并放入新键
mapList.forEach(map ->{
map.put("new time",map.remove("time"));
});
我得到了答案
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class HelloWorld {
public static void main(String... args) {
List<Map<String,Object>> mapList=new ArrayList<Map<String,Object>>();
Map<String, Object> myMap1=new HashMap<String, Object>();
myMap1.put("name", "jai");
myMap1.put("time", Instant.now());
mapList.add(myMap1);
Map<String, Object> myMap2=new HashMap<String, Object>();
myMap2.put("name", "kishan");
myMap2.put("time", Instant.now());
mapList.add(myMap2);
System.out.println(mapList);
mapList.forEach(oneMap -> replaceKeyBy(oneMap));
System.out.println(mapList);
}
private static void replaceKeyBy(Map<String, Object> map) {
map.replace("time",Instant.now().plus(10, ChronoUnit.DAYS));
}
}
导入java.time.Instant;
导入java.time.temporal.ChronoUnit;
导入java.util.ArrayList;
导入java.util.HashMap;
导入java.util.List;
导入java.util.Map;
公共类HelloWorld{
公共静态void main(字符串…参数){
List mapList=new ArrayList();
Map myMap1=新的HashMap();
myMap1.put(“名称”、“jai”);
myMap1.put(“time”,Instant.now());
mapList.add(myMap1);
Map myMap2=新的HashMap();
myMap2.put(“名称”、“基山”);
myMap2.put(“time”,Instant.now());
mapList.add(myMap2);
System.out.println(映射列表);
forEach(oneMap->replaceKeyBy(oneMap));
System.out.println(映射列表);
}
私有静态void replaceKeyBy(映射映射){
map.replace(“time”,Instant.now().plus(10,ChronoUnit.DAYS));
}
}