使用 ConfigurationProperties 以通用方式填充 Map
Using ConfigurationProperties to fill Map in generic way
我想知道，是否有一种通用方法可以用您只知道前缀的属性填充地图。
假设有一堆属性，例如
namespace.prop1=value1
namespace.prop2=value2
namespace.iDontKnowThisNameAtCompileTime=anothervalue
我想要一种通用的方法来在地图中填充此 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，而不是遍历环境中的所有 PropertySources？
谢谢
汉舍格
我给自己写了一个 MapFilter class 来有效地处理这个问题。本质上，您创建一个 Map 然后通过为键指定前缀来过滤它。为了方便起见，还有一个采用 Properties 的构造函数。
请注意，这只会过滤主地图。应用于过滤地图的任何更改也应用于底图，包括删除等，但显然对主地图的更改不会反映在过滤地图中，直到某些事情导致重建。
过滤已过滤的地图也非常容易（且高效）。
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);
}
}
只要您愿意将每个 属性 添加到地图中，而不仅仅是那些您事先不知道的，您可以使用 @ConfigurationProperties 来做到这一点。如果你想获取 namespace 下面的所有内容，那么你需要使用空前缀并为名为 namespace:
的地图提供 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 方法检索映射，以便它可以向其中添加属性。具有这些属性：
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}
如果属性嵌套更深，例如：
namespace.foo.bar.a=alpha
namespace.foo.bar.b=bravo
namespace.foo.bar.c=charlie
然后你将使用namespace.foo作为前缀，并将CustomProperties上的namespace和getNamespace分别重命名为bar和getBar .
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，您可以使用该注释引用任何要处理的 bean，而不是为它们提供 @Bean 方法，或使用 @Component 让组件扫描发现它们：
@SpringBootApplication
@EnableConfigurationProperties(CustomProperties.class)
public class YourApplication {
// …
}
除此之外，我的问题是我没有多个简单的 key/value 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 Jake 的建议，我尝试将 Map 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]
}
}
工作起来很有魅力，
谢谢！
我快要疯了试图理解为什么@Andy 的 wasn't working for me (as in, the Map was remaining empty) just to realize that I had Lombok's @Builder annotation getting in the way, which added a non-empty constructor. I'm adding this answer to emphasize that in order for @ConfigurationProperties to work on Map, the value type must have a No-Arguments constructor. This is also mentioned in Spring's documentation:
Such arrangement relies on a default empty constructor and getters and setters are usually mandatory ...
我希望这会为其他人节省一些时间。
我想知道，是否有一种通用方法可以用您只知道前缀的属性填充地图。
假设有一堆属性，例如
namespace.prop1=value1
namespace.prop2=value2
namespace.iDontKnowThisNameAtCompileTime=anothervalue
我想要一种通用的方法来在地图中填充此 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，而不是遍历环境中的所有 PropertySources？
谢谢 汉舍格
我给自己写了一个 MapFilter class 来有效地处理这个问题。本质上，您创建一个 Map 然后通过为键指定前缀来过滤它。为了方便起见，还有一个采用 Properties 的构造函数。
请注意，这只会过滤主地图。应用于过滤地图的任何更改也应用于底图，包括删除等，但显然对主地图的更改不会反映在过滤地图中，直到某些事情导致重建。
过滤已过滤的地图也非常容易（且高效）。
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);
}
}
只要您愿意将每个 属性 添加到地图中，而不仅仅是那些您事先不知道的，您可以使用 @ConfigurationProperties 来做到这一点。如果你想获取 namespace 下面的所有内容，那么你需要使用空前缀并为名为 namespace:
@ConfigurationProperties("")
public class CustomProperties {
private final Map<String, String> namespace = new HashMap<>();
public Map<String, String> getNamespace() {
return namespace;
}
}
Spring Boot 使用 getNamespace 方法检索映射，以便它可以向其中添加属性。具有这些属性：
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}
如果属性嵌套更深，例如：
namespace.foo.bar.a=alpha
namespace.foo.bar.b=bravo
namespace.foo.bar.c=charlie
然后你将使用namespace.foo作为前缀，并将CustomProperties上的namespace和getNamespace分别重命名为bar和getBar .
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，您可以使用该注释引用任何要处理的 bean，而不是为它们提供 @Bean 方法，或使用 @Component 让组件扫描发现它们：
@SpringBootApplication
@EnableConfigurationProperties(CustomProperties.class)
public class YourApplication {
// …
}
除此之外，我的问题是我没有多个简单的 key/value 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 Jake 的建议，我尝试将 Map 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]
}
}
工作起来很有魅力， 谢谢！
我快要疯了试图理解为什么@Andy 的 Map was remaining empty) just to realize that I had Lombok's @Builder annotation getting in the way, which added a non-empty constructor. I'm adding this answer to emphasize that in order for @ConfigurationProperties to work on Map, the value type must have a No-Arguments constructor. This is also mentioned in Spring's documentation:
Such arrangement relies on a default empty constructor and getters and setters are usually mandatory ...
我希望这会为其他人节省一些时间。