我想知道,如果有一种通用方法来填充带有属性的地图,您只需要知道前缀。
假设有很多属性,比如
namespace.prop1=value1
namespace.prop2=value2
namespace.iDontKnowThisNameAtCompileTime=anothervalue
我希望有一种通用的方法在地图中填充此属性,例如
@Component
@ConfigurationProperties("namespace")
public class MyGenericProps {
private Map<String, String> propmap = new HashMap<String, String>();
// setter and getter for propmap omitted
public Set<String> returnAllKeys() {
return propmap.keySet();
}
}
或者是否有另一种方便的方法来收集具有特定前缀的所有属性,而不是迭代环境中的所有PropertySource?
由于 Hansjoerg
答案 0 :(得分:59)
只要您乐意将每个属性添加到地图中,而不仅仅是您事先不知道的属性,您可以使用@ConfigurationProperties
执行此操作。如果你想抓住namespace
下面的所有内容,那么你需要使用一个空前缀并为名为namespace
的地图提供一个getter:
@ConfigurationProperties("")
public class CustomProperties {
private final Map<String, String> namespace = new HashMap<>();
public Map<String, String> getNamespace() {
return namespace;
}
}
Spring Boot使用getNamespace
方法检索地图,以便可以向其添加属性。有了这些属性:
namespace.a=alpha
namespace.b=bravo
namespace.c=charlie
namespace
地图将包含三个条目:
{a=alpha, b=bravo, c=charlie}
如果属性嵌套得更深,例如:
namespace.foo.bar.a=alpha
namespace.foo.bar.b=bravo
namespace.foo.bar.c=charlie
然后您使用namespace.foo
作为前缀,并分别在namespace
上将getNamespace
和CustomProperties
重命名为bar
和getBar
。< / p>
请注意,您应该将@EnableConfigurationProperties
应用于您的配置,以启用对@ConfigurationProperties
的支持。然后,您可以使用该批注引用要处理的任何bean,而不是为它们提供@Bean
方法,或使用@Component
通过组件扫描发现它们:
@SpringBootApplication
@EnableConfigurationProperties(CustomProperties.class)
public class YourApplication {
// …
}
答案 1 :(得分:1)
我自己写了一个MapFilter
类来有效地处理这个问题。实质上,您创建一个Map
,然后通过指定密钥的前缀来过滤它。为方便起见,还有一个构造函数需要Properties
。
请注意,这只会过滤主地图。应用于过滤后的地图的任何更改也会应用于基本地图,包括删除等,但显然主要地图的更改将不会反映在已过滤的地图中,直到某些内容导致重建。
过滤已过滤的地图也非常容易(也很有效)。
public class MapFilter<T> implements Map<String, T> {
// The enclosed map -- could also be a MapFilter.
final private Map<String, T> map;
// Use a TreeMap for predictable iteration order.
// Store Map.Entry to reflect changes down into the underlying map.
// The Key is the shortened string. The entry.key is the full string.
final private Map<String, Map.Entry<String, T>> entries = new TreeMap<>();
// The prefix they are looking for in this map.
final private String prefix;
public MapFilter(Map<String, T> map, String prefix) {
// Store my backing map.
this.map = map;
// Record my prefix.
this.prefix = prefix;
// Build my entries.
rebuildEntries();
}
public MapFilter(Map<String, T> map) {
this(map, "");
}
private synchronized void rebuildEntries() {
// Start empty.
entries.clear();
// Build my entry set.
for (Map.Entry<String, T> e : map.entrySet()) {
String key = e.getKey();
// Retain each one that starts with the specified prefix.
if (key.startsWith(prefix)) {
// Key it on the remainder.
String k = key.substring(prefix.length());
// Entries k always contains the LAST occurrence if there are multiples.
entries.put(k, e);
}
}
}
@Override
public String toString() {
return "MapFilter (" + prefix + ") of " + map + " containing " + entrySet();
}
// Constructor from a properties file.
public MapFilter(Properties p, String prefix) {
// Properties extends HashTable<Object,Object> so it implements Map.
// I need Map<String,T> so I wrap it in a HashMap for simplicity.
// Java-8 breaks if we use diamond inference.
this(new HashMap<String, T>((Map) p), prefix);
}
// Helper to fast filter the map.
public MapFilter<T> filter(String prefix) {
// Wrap me in a new filter.
return new MapFilter<>(this, prefix);
}
// Count my entries.
@Override
public int size() {
return entries.size();
}
// Are we empty.
@Override
public boolean isEmpty() {
return entries.isEmpty();
}
// Is this key in me?
@Override
public boolean containsKey(Object key) {
return entries.containsKey(key);
}
// Is this value in me.
@Override
public boolean containsValue(Object value) {
// Walk the values.
for (Map.Entry<String, T> e : entries.values()) {
if (value.equals(e.getValue())) {
// Its there!
return true;
}
}
return false;
}
// Get the referenced value - if present.
@Override
public T get(Object key) {
return get(key, null);
}
// Get the referenced value - if present.
public T get(Object key, T dflt) {
Map.Entry<String, T> e = entries.get((String) key);
return e != null ? e.getValue() : dflt;
}
// Add to the underlying map.
@Override
public T put(String key, T value) {
T old = null;
// Do I have an entry for it already?
Map.Entry<String, T> entry = entries.get(key);
// Was it already there?
if (entry != null) {
// Yes. Just update it.
old = entry.setValue(value);
} else {
// Add it to the map.
map.put(prefix + key, value);
// Rebuild.
rebuildEntries();
}
return old;
}
// Get rid of that one.
@Override
public T remove(Object key) {
// Do I have an entry for it?
Map.Entry<String, T> entry = entries.get((String) key);
if (entry != null) {
entries.remove(key);
// Change the underlying map.
return map.remove(prefix + key);
}
return null;
}
// Add all of them.
@Override
public void putAll(Map<? extends String, ? extends T> m) {
for (Map.Entry<? extends String, ? extends T> e : m.entrySet()) {
put(e.getKey(), e.getValue());
}
}
// Clear everything out.
@Override
public void clear() {
// Just remove mine.
// This does not clear the underlying map - perhaps it should remove the filtered entries.
for (String key : entries.keySet()) {
map.remove(prefix + key);
}
entries.clear();
}
@Override
public Set<String> keySet() {
return entries.keySet();
}
@Override
public Collection<T> values() {
// Roll them all out into a new ArrayList.
List<T> values = new ArrayList<>();
for (Map.Entry<String, T> v : entries.values()) {
values.add(v.getValue());
}
return values;
}
@Override
public Set<Map.Entry<String, T>> entrySet() {
// Roll them all out into a new TreeSet.
Set<Map.Entry<String, T>> entrySet = new TreeSet<>();
for (Map.Entry<String, Map.Entry<String, T>> v : entries.entrySet()) {
entrySet.add(new Entry<>(v));
}
return entrySet;
}
/**
* An entry.
*
* @param <T>
*
* The type of the value.
*/
private static class Entry<T> implements Map.Entry<String, T>, Comparable<Entry<T>> {
// Note that entry in the entry is an entry in the underlying map.
private final Map.Entry<String, Map.Entry<String, T>> entry;
Entry(Map.Entry<String, Map.Entry<String, T>> entry) {
this.entry = entry;
}
@Override
public String getKey() {
return entry.getKey();
}
@Override
public T getValue() {
// Remember that the value is the entry in the underlying map.
return entry.getValue().getValue();
}
@Override
public T setValue(T newValue) {
// Remember that the value is the entry in the underlying map.
return entry.getValue().setValue(newValue);
}
@Override
public boolean equals(Object o) {
if (!(o instanceof Entry)) {
return false;
}
Entry e = (Entry) o;
return getKey().equals(e.getKey()) && getValue().equals(e.getValue());
}
@Override
public int hashCode() {
return getKey().hashCode() ^ getValue().hashCode();
}
@Override
public String toString() {
return getKey() + "=" + getValue();
}
@Override
public int compareTo(Entry<T> o) {
return getKey().compareTo(o.getKey());
}
}
// Simple tests.
public static void main(String[] args) {
String[] samples = {
"Some.For.Me",
"Some.For.You",
"Some.More",
"Yet.More"};
Map map = new HashMap();
for (String s : samples) {
map.put(s, s);
}
Map all = new MapFilter(map);
Map some = new MapFilter(map, "Some.");
Map someFor = new MapFilter(some, "For.");
System.out.println("All: " + all);
System.out.println("Some: " + some);
System.out.println("Some.For: " + someFor);
}
}
答案 2 :(得分:0)
除此之外,我的问题是我没有多个简单的键/值属性,而是整个对象:
zuul:
routes:
query1:
path: /api/apps/test1/query/**
stripPrefix: false
url: "https://test.url.com/query1"
query2:
path: /api/apps/test2/query/**
stripPrefix: false
url: "https://test.url.com/query2"
index1:
path: /api/apps/*/index/**
stripPrefix: false
url: "https://test.url.com/index"
按照杰克的建议,我试图将地图与Pojo一起使用,如下所示:
@ConfigurationProperties("zuul")
public class RouteConfig {
private Map<String, Route> routes = new HashMap<>();
public Map<String, Route> getRoutes() {
return routes;
}
public static class Route {
private String path;
private boolean stripPrefix;
String url;
// [getters + setters]
}
}
像魅力一样运作, 谢谢!
答案 3 :(得分:0)
我发疯了,试图理解为什么@Andy的answer对我不起作用(例如Map
仍然是空的)只是为了意识到我有Lombok的@Builder
注释方式,它添加了一个非空的构造函数。我要添加此答案,以强调为了使@ConfigurationProperties
在Map
上运行,值类型必须具有No-Arguments构造函数。在Spring的documentation中也提到了这一点:
这种安排依赖于默认的空构造函数,而getter和setter通常是强制性的...
我希望这可以节省其他人的时间。