输出结果有时，生成天气数据在前面，但是获取到的值没有错，怎么回事？

package com.xww.weather;

public class GenerateWeather implements Runnable {
	Weather weather;

	public GenerateWeather(Weather weather) {
		this.weather = weather;
	}

	@Override
	public void run() {
		for (int i = 0; i < 100; i++) {
			weather.generate();
			System.out.println("生成天气数据"+weather);
			try {
				Thread.sleep(5000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}

}

package com.xww.weather;

public class ReadWeather implements Runnable {
	Weather weather;
	
	public ReadWeather(Weather weather) {
		this.weather = weather;
	}

	@Override
	public void run() {
		for(int i=0;i<100;i++) {
			weather.read();
			System.out.println("读取天气数据"+weather);
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}

	}

}

package com.xww.weather;

public class WeatherTest {

	public static void main(String[] args) {
		Weather one = new Weather();
		new Thread(new GenerateWeather(one)).start();
		new Thread(new ReadWeather(one)).start();
	}

}

package com.xww.weather;

public class Weather {
	private int temperature;
	private int humidity;
	boolean flag=false;
	public int getTemperature() {
		return temperature;
	}

	public void setTemperature(int temperature) {
		this.temperature = temperature;
	}

	public int getHumidity() {
		return humidity;
	}

	public void setHumidity(int humidity) {
		this.humidity = humidity;
	}

	public synchronized void generate() {
		if(flag) {
			try {
				wait();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		temperature = (int) (Math.random() * 40);
		humidity = (int) (Math.random() * 100);
		this.setTemperature(temperature);
		this.setHumidity(humidity);
		flag=true;
		notifyAll();
	}

	public synchronized void read() {
		if(!flag) {
			try {
				wait();
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		humidity = this.getHumidity();
		temperature = this.getTemperature();
		flag=false;
		notifyAll();
	}

	@Override
	public String toString() {
		return "[温度：" + temperature + ", 湿度：" + humidity + "]";
	}

}

package com.xww.weather;

public class GenerateWeather implements Runnable {

Weather weather;

public GenerateWeather(Weather weather) {

this.weather = weather;

}

@Override

public void run() {

for (int i = 0; i < 100; i++) {

weather.generate();

System.out.println("生成天气数据"+weather);

try {

Thread.sleep(5000);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

}

}

package com.xww.weather;

public class ReadWeather implements Runnable {

Weather weather;

public ReadWeather(Weather weather) {

this.weather = weather;

}

@Override

public void run() {

for(int i=0;i<100;i++) {

weather.read();

System.out.println("读取天气数据"+weather);

try {

Thread.sleep(100);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}

package com.xww.weather;

public class WeatherTest {

public static void main(String[] args) {

Weather one = new Weather();

new Thread(new GenerateWeather(one)).start();

new Thread(new ReadWeather(one)).start();

}

}

同学你好，建议你贴出复制后的完整代码，方便老师更好更快的解决问题。如果我的回答解决了你的疑惑，请采纳。祝：学习愉快~