可以使用如下的代码来实现:
```java
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
public class WorldCupChampion {
public static void main(String[] args) {
Map<Integer, String> champions = new HashMap<>();
champions.put(1930, "乌拉圭");
champions.put(1934, "意大利");
champions.put(1938, "意大利");
champions.put(1950, "乌拉圭");
champions.put(1954, "西德");
champions.put(1958, "巴西");
champions.put(1962, "巴西");
champions.put(1966, "英格兰");
champions.put(1970, "巴西");
champions.put(1974, "西德");
champions.put(1978, "阿根廷");
champions.put(1982, "意大利");
champions.put(1986, "阿根廷");
champions.put(1990, "西德");
champions.put(1994, "巴西");
champions.put(1998, "法国");
champions.put(2002, "巴西");
champions.put(2006, "意大利");
champions.put(2010, "西班牙");
champions.put(2014, "德国");
champions.put(2018, "法国");
Scanner scanner = new Scanner(System.in);
System.out.print("请输入一个年份:");
int year = scanner.nextInt();
String champion = champions.get(year);
if (champion != null) {
System.out.println(year + "年的世界杯冠军是:" + champion);
} else {
System.out.println(year + "年没有举办世界杯。");
}
}
}
```
以上代码中,我们使用了一个 `HashMap` 来存储历届世界杯的冠军。然后从命令行读入一个年份,并且查找该年份的冠军。如果找到了,就输出冠军的名称;如果没有找到,就输出相应的提示信息。