请根据观察者模式，用Java语言设计并实现气象站程序。

[{"title":"（ 19 个子文件 11KB ） 请根据观察者模式，用Java语言设计并实现气象站程序。","children":[{"title":"WeatherStation","children":[{"title":".project <span style='color:#111;'> 390B </span>","children":null,"spread":false},{"title":"src","children":[{"title":"cn","children":[{"title":"edu","children":[{"title":"qust","children":[{"title":"dp","children":[{"title":"object","children":[{"title":"CurrentConditionsDisplay.java <span style='color:#111;'> 1003B </span>","children":null,"spread":false},{"title":"StatisticsDisplay.java <span style='color:#111;'> 1.48KB </span>","children":null,"spread":false},{"title":"WeatherStation.java <span style='color:#111;'> 625B </span>","children":null,"spread":false},{"title":"WeatherData.java <span style='color:#111;'> 1.24KB </span>","children":null,"spread":false},{"title":"ForecastDisplay.java <span style='color:#111;'> 1.47KB </span>","children":null,"spread":false}],"spread":true},{"title":"Interface","children":[{"title":"Observer.java <span style='color:#111;'> 150B </span>","children":null,"spread":false},{"title":"Subject.java <span style='color:#111;'> 188B </span>","children":null,"spread":false},{"title":"DisplayElement.java <span style='color:#111;'> 100B </span>","children":null,"spread":false}],"spread":true}],"spread":true}],"spread":true}],"spread":true}],"spread":true}],"spread":true},{"title":".settings","children":[{"title":"org.eclipse.jdt.core.prefs <span style='color:#111;'> 598B </span>","children":null,"spread":false}],"spread":true},{"title":".classpath <span style='color:#111;'> 301B </span>","children":null,"spread":false},{"title":"bin","children":[{"title":"cn","children":[{"title":"edu","children":[{"title":"qust","children":[{"title":"dp","children":[{"title":"object","children":[{"title":"CurrentConditionsDisplay.class <span style='color:#111;'> 1.45KB </span>","children":null,"spread":false},{"title":"WeatherData.class <span style='color:#111;'> 1.54KB </span>","children":null,"spread":false},{"title":"StatisticsDisplay.class <span style='color:#111;'> 2.13KB </span>","children":null,"spread":false},{"title":"ForecastDisplay.class <span style='color:#111;'> 1.88KB </span>","children":null,"spread":false},{"title":"WeatherStation.class <span style='color:#111;'> 1.11KB </span>","children":null,"spread":false}],"spread":true},{"title":"Interface","children":[{"title":"DisplayElement.class <span style='color:#111;'> 158B </span>","children":null,"spread":false},{"title":"Subject.class <span style='color:#111;'> 246B </span>","children":null,"spread":false},{"title":"Observer.class <span style='color:#111;'> 148B </span>","children":null,"spread":false}],"spread":true}],"spread":true}],"spread":true}],"spread":true}],"spread":true}],"spread":true}],"spread":true}],"spread":true}]