Read Day5 30 minutes before going to bed every day_ All key values in the map, how to obtain all value values

How to get map Middle all key value , All value value , And get all at the same time key and value value ？

1. obtain map All key values in （keySet Method ）, The output adopts lambda expression

Map<String, Object> attrMap = Files.readAttributes(path, "*", LinkOption.NOFOLLOW_LINKS);
        // obtain map All key values in 
Set<String> keySet = attrMap.keySet();
keySet.forEach(key -> System.out.println(key));

2. obtain map All of value value ,（values Method ）, The output adopts foreach

Collection<Object> values = attrMap.values();
for (Object value: values) {
    
     System.out.println("map Medium value The value is ：" + value);
}

3. Simultaneous acquisition key value and value value （entrySet Method ）. Output adopts two methods ,iterator iterator perhaps foreach loop ,lambda Expression form

 // Can be obtained at the same time map Medium  key value   and  value value 
Set<Map.Entry<String, Object>> entrySet = attrMap.entrySet();
Iterator<Map.Entry<String, Object>> iterator = entrySet.iterator();
while (iterator.hasNext()) {
    
    Map.Entry<String, Object> next = iterator.next();
    String key = next.getKey();
    Object value = next.getValue();
    System.out.println("key The value is "+ key+ " value The value is ：" + value);
}
System.out.println("============ use  foreach  loop , Get key value and value value ============");
entrySet.forEach(entry -> {
    
    String key = entry.getKey();
    Object value = entry.getValue();
    System.out.println("key The value is "+ key+ " value The value is ：" + value);
});

All the codes in this test ：

import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.file.*;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.stream.Stream;

/** * @Author Janson * @Date 2022/4/20 9:17 * @Version 1.0 */
public class Day4_Files {
    
    public static void main(String[] args) throws Exception  {
    
        Path path = Paths.get("O:\\code\\BeforeSleeping30m\\testData");


        // Get the properties of the file 
        //{@code "*"} then all attributes are read.
        // LinkOption.NOFOLLOW_LINKS  Don't follow the symbolic connection 
        Map<String, Object> attrMap = Files.readAttributes(path, "*", LinkOption.NOFOLLOW_LINKS);
        // obtain map All key values in 
        Set<String> keySet = attrMap.keySet();
        keySet.forEach(key -> System.out.println(key));
        // obtain map All of  value value 
        Collection<Object> values = attrMap.values();
        for (Object value: values) {
    
            System.out.println("map Medium value The value is ：" + value);
        }
        // Can be obtained at the same time map Medium  key value   and  value value 
        Set<Map.Entry<String, Object>> entrySet = attrMap.entrySet();
        Iterator<Map.Entry<String, Object>> iterator = entrySet.iterator();
        while (iterator.hasNext()) {
    
            Map.Entry<String, Object> next = iterator.next();
            String key = next.getKey();
            Object value = next.getValue();
            System.out.println("key The value is "+ key+ " value The value is ：" + value);
        }
        System.out.println("============ use  foreach  loop , Get key value and value value ============");
        entrySet.forEach(entry -> {
    
            String key = entry.getKey();
            Object value = entry.getValue();
            System.out.println("key The value is "+ key+ " value The value is ：" + value);
        });

    }
}