比较类
public class name implements Comparator<f>{
@Override
public int compare(f o1, f o2) {
return o2.getName().compareTo(o1.getName());
}
}
映射类
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((name == null) ? 0 : name.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
f other = (f) obj;
if (name == null) {
if (other.name != null)
return false;
} else if (!name.equals(other.name))
return false;
return true;
}
@Override
public String toString() {
return "f [name=" + name + "]";
}
public f(String name) {
super();
this.name = name;
}
public f() {
super();
}
测试
package pro1218test;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
ArrayList<f> s=new ArrayList<>();
f f1=new f("apple");
f f2=new f("grape");
f f3=new f("banana");
f f4=new f("pear");
s.add(f1);
s.add(f2);
s.add(f3);
s.add(f4);
System.out.println(s);
f max=Collections.max(s,new name());
System.out.println(max);
f min =Collections.min(s,new name());
System.out.println(min);
Collections.sort(s,new name());
System.out.println(s);
}