JAVA排序(二) Comparator接口
接着说关于Comparator接口，
java.util Interface Comparator<T>(该泛型指定的是被比较的类)，使用该接口不需要在待比较类进行比较操作，即在不修改源码的情况下进行比较（如代码交付后），
与Comparable相比稍微复杂，但是还是很方便~~
首先是待比较类，这里是一个记录温度与湿度的为了与上面做区分，在这里叫EnvironmentForms类：
public class EnvironmentForms {
/**温度*/
private float temp;
/**湿度*/
private float hum;
public float getTemp() {
return temp;
}
public void setTemp(float temp) {
this.temp = temp;
}
public float getHum() {
return hum;
}
public void setHum(float hum) {
this.hum = hum;
}
/**
* 无参构造
*/
public EnvironmentForms(){}
/**
* 有参构造
* @param temp 温度
* @param hum 湿度
*/
public EnvironmentForms(float temp, float hum) {
super();
this.temp = temp;
this.hum = hum;
}
@Override
public String toString() {
return "EnvironmentForm [温度=" + temp + ", 湿度=" + hum + "]\n";
}
}
在不修改此类的情况下，还是对温度进行降序排列，当温度相等湿度降序排列，
首先写一个比较规则类实现Comparator接口，
实现compare int compare(T o1,T o2)与equals boolean equals(Object obj)（该方法这里没有复写），代码如下：
import java.util.Comparator;
public class EnvironmentComparator implements Comparator<EnvironmentForms> {
@Override
public int compare(EnvironmentForms env1, EnvironmentForms env2) {
//大于所给温度则返回-1
if(env1.getTemp()>env2.getTemp()){
return -1;
}else if(env1.getTemp()<env2.getTemp()){
//小于所给温度返回1
return 1;
}else{
//大于所给湿度返回-1
if(env1.getHum()>env2.getHum()){
return -1;
//小于所给湿度返回1
}else if(env1.getTemp()<env2.getHum()){
return 1;
}
}
return 0;
}
}
最后进行测试~~代码如下:
import java.util.Arrays;
public class ComparatorTestMain {
public static void main(String[] args) {
EnvironmentForms env[] = {new EnvironmentForms(28.5f,50.1f),
new EnvironmentForms(28.5f,60.1f),
new EnvironmentForms(28.5f,40.1f),
new EnvironmentForms(17.5f,50.1f),
new EnvironmentForms(37.5f,50.1f)};
System.out.println("********排序前********");
System.out.println(Arrays.toString(env));
System.out.println("********排序后********");
Arrays.sort(env, new EnvironmentComparator());
System.out.println(Arrays.toString(env));
}
}
运行结果~~
********排序前******** [EnvironmentForm [温度=28.5, 湿度=50.1] , EnvironmentForm [温度=28.5, 湿度=60.1] , EnvironmentForm [温度=28.5, 湿度=40.1] , EnvironmentForm [温度=17.5, 湿度=50.1] , EnvironmentForm [温度=37.5, 湿度=50.1] ] ********排序后******** [EnvironmentForm [温度=37.5, 湿度=50.1] , EnvironmentForm [温度=28.5, 湿度=60.1] , EnvironmentForm [温度=28.5, 湿度=50.1] , EnvironmentForm [温度=28.5, 湿度=40.1] , EnvironmentForm [温度=17.5, 湿度=50.1] ]