Java 树映射比较器函数重载
我试图添加一个自定义比较器来对地图进行排序, 下面是我的比较Java 树映射比较器函数重载,java,comparator,treemap,Java,Comparator,Treemap,我试图添加一个自定义比较器来对地图进行排序, 下面是我的比较 public static class MyComparator implements Comparator<String> { private String NAME_REGEX = "M\\d+"; public int compare(String o1, String o2) { if (o1.matches(NAME_REGEX) && o2.matches
public static class MyComparator implements Comparator<String> {
private String NAME_REGEX = "M\\d+";
public int compare(String o1, String o2) {
if (o1.matches(NAME_REGEX) && o2.matches(NAME_REGEX)) {
try {
return Integer.parseInt(o1.substring(1)) - Integer.parseInt(o2.substring(1));
} catch (NumberFormatException ex) {
return o1.compareTo(o2);
}
} else {
return o1.compareTo(o2);
}
}
}
公共静态类MyComparator实现Comparator{
私有字符串名称_REGEX=“M\\d+”;
公共整数比较(字符串o1,字符串o2){
if(o1.匹配(NAME_REGEX)和&o2.匹配(NAME_REGEX)){
试一试{
返回Integer.parseInt(o1.substring(1))-Integer.parseInt(o2.substring(1));
}捕获(NumberFormatException ex){
返回o1。与(o2)相比;
}
}否则{
返回o1。与(o2)相比;
}
}
}
我的用法如下:
public static void main(String[] args) {
Map<String, String> map = new TreeMap<String, String>() {
@Override
public Comparator<? super String> comparator() {
return new MyComparator();
}
};
map.put("M10", "data");
map.put("M9", "data");
map.put("M11", "data");
map.put("M12", "data");
map.put("M6", "data");
for (String keys : map.keySet()) {
System.out.print(keys);
}
}
publicstaticvoidmain(字符串[]args){
Map Map=newtreemap(){
@凌驾
公共比较器查看TreeMap.put
的源代码时,我们看到它直接引用比较器:
public V put(K key, V value) {
...
//cpr is the the comparator being used
Comparator<? super K> cpr = comparator;
....
}
public V put(K键,V值){
...
//cpr是正在使用的比较仪
Comparatorthank you.我阅读了tree map的源代码,并且知道只有当我将这个map实例传递给另一个maps“putAll”方法时,才会调用我重写的函数。