spring服務定位器，可在任何地方獲取bean，springbean
通過持有的Spring應用場景ApplicationContext，可在任何地方獲取bean。
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1 import org.apache.commons.logging.Log;
2 import org.apache.commons.logging.LogFactory;
3 import org.springframework.beans.factory.DisposableBean;
4 import org.springframework.context.ApplicationContext;
5 import org.springframework.context.ApplicationContextAware;
6
7 /**
8 * 服務定位器
9 * 持有Spring的應用場景, 可在任何地方獲取bean.
10 */
11 public final class ServiceLocator implements ApplicationContextAware, DisposableBean {
12
13 private static Log logger = LogFactory.getLog(ServiceLocator.class);
14 private static ApplicationContext context = null;
15
16 /**
17 * 實現ApplicationContextAware接口, 注入Context到靜態變量中.
18 * @param context
19 */
20 @Override
21 public void setApplicationContext(ApplicationContext context) {
22 logger.debug("Injected the ApplicationContext into ServiceLocator:" + context);
23 if (ServiceLocator.context != null) {
24 logger.debug("[------------ ApplicationContext in the ServiceLocator " +
25 "is covered, as the original ApplicationContext is:"
26 + ServiceLocator.context + " ------------]");
27 }
28 ServiceLocator.context = context;
29 }
30
31 /**
32 * 實現DisposableBean接口,在Context關閉時清理靜態變量.
33 */
34 @Override
35 public void destroy() throws Exception {
36 ServiceLocator.clear();
37 }
38
39 /**
40 * 取得存儲在靜態變量中的ApplicationContext.
41 * @return
42 */
43 public static ApplicationContext getApplicationContext() {
44 assertContextInjected();
45 return context;
46 }
47
48 /**
49 * 從Spring的應用場景中取得Bean, 自動轉型為所賦值對象的類型.
50 * @param name bean名稱
51 * @return bean對象
52 */
53 @SuppressWarnings("unchecked")
54 public static <T> T getService(String name) {
55 assertContextInjected();
56 return (T) context.getBean(name);
57 }
58
59 /**
60 * 從Spring的應用場景中取得Bean, 自動轉型為所賦值對象的類型.
61 * @param requiredType bean類
62 * @return bean對象
63 */
64 public static <T> T getService(Class<T> requiredType) {
65 assertContextInjected();
66 return context.getBean(requiredType);
67 }
68
69 /**
70 * 清除ServiceLocator中的ApplicationContext
71 */
72 public static void clear() {
73 logger.debug("Clear ApplicationContext in ServiceLocator :" + context);
74 context = null;
75 }
76
77 /**
78 * 檢查ApplicationContext不為空.
79 */
80 private static void assertContextInjected() {
81 if (context == null) {
82 throw new IllegalStateException("ApplicaitonContext not injected, " +
83 "as defined in the context.xml ServiceLocator");
84 }
85 }
86 }
View Code
調用getService函數，分為按名稱和類型獲取。
1 /**
2 * 從Spring的應用場景中取得Bean, 自動轉型為所賦值對象的類型.
3 * @param name bean名稱
4 * @return bean對象
5 */
6 @SuppressWarnings("unchecked")
7 public static <T> T getService(String name) {
8 assertContextInjected();
9 return (T) context.getBean(name);
10 }
11
12 /**
13 * 從Spring的應用場景中取得Bean, 自動轉型為所賦值對象的類型.
14 * @param requiredType bean類
15 * @return bean對象
16 */
17 public static <T> T getService(Class<T> requiredType) {
18 assertContextInjected();
19 return context.getBean(requiredType);
20 }
