Java中的 AbstractMap.SimpleEntry hashCode() 方法及示例
AbstractMap.SimpleEntry
AbstractMap.SimpleEntry
映射条目 e 的哈希码可以通过以下方式计算:
(e.getKey()==null ? 0 : e.getKey().hashCode()) ^
(e.getValue()==null ? 0 : e.getValue().hashCode())
句法:
public int hashCode()
参数:此方法不接受任何内容。
返回值:此方法返回此映射条目的哈希码值。
下面的程序说明了 hashCode() 方法:
方案一:
// Java program to demonstrate
// AbstractMap.SimpleEntry.hashCode() method
import java.util.*;
import java.util.AbstractMap.SimpleEntry;
public class GFG {
@SuppressWarnings({ "unchecked", "rawtypes" })
public static void main(String[] args)
{
// create a ArrayList of Map
ArrayList >
arrayList
= new ArrayList >();
// add values
arrayList.add(new AbstractMap.SimpleEntry(0, 123));
arrayList.add(new AbstractMap.SimpleEntry(1, 130));
arrayList.add(new AbstractMap.SimpleEntry(2, 994));
// print keys
for (int i = 0; i < arrayList.size(); i++) {
// get map from list
AbstractMap.SimpleEntry
map
= arrayList.get(i);
// get value from map using hashCode()
int value = map.hashCode();
System.out.println("HashCode = " + value);
}
}
}
输出:
HashCode = 123
HashCode = 131
HashCode = 992
方案二:
// Java program to demonstrate
// AbstractMap.SimpleEntry.hashCode() method
import java.util.*;
public class GFG {
@SuppressWarnings({ "unchecked", "rawtypes" })
public static void main(String[] args)
{
// create a ArrayList of Map
ArrayList >
arrayList
= new ArrayList >();
// add values
arrayList.add(new AbstractMap
.SimpleEntry(" 001AB ", " Emp 1"));
arrayList.add(new AbstractMap
.SimpleEntry(" 011AC ", " Emp 2"));
arrayList.add(new AbstractMap
.SimpleEntry(" 111AD ", " Emp 3"));
arrayList.add(new AbstractMap
.SimpleEntry(" 101BE ", " Emp 4"));
arrayList.add(new AbstractMap
.SimpleEntry(" 110CE ", " Emp 5"));
// print keys
for (int i = 0; i < arrayList.size(); i++) {
// get map from list
AbstractMap.SimpleEntry
map
= arrayList.get(i);
// get hashcode value from map using hashCode()
int value = map.hashCode();
System.out.println("hashCode = " + value);
}
}
}
输出:
hashCode = -873386249
hashCode = -874293612
hashCode = -910934441
hashCode = -910552137
hashCode = -910906733
参考资料: https: Java/util/AbstractMap.SimpleEntry.html#hashCode()