本文介紹了詳解spring切面使用傳遞給被通知方法的參數(shù)，分享給大家，具體如下：
場(chǎng)景：
BlankDisc代表CD實(shí)體，可以通過(guò)playTrack()方法直接播放某一個(gè)磁道中的歌曲。
需求是記錄每個(gè)磁道被播放的次數(shù)。
一種方法就是修改playTrack()方法，直接在每次調(diào)用的時(shí)候記錄這個(gè)數(shù)量。但是，記錄磁道的播放次數(shù)與播放本身是不同的關(guān)注點(diǎn)，因此不應(yīng)該屬于playTrack()方法。這應(yīng)該是切面要完成的任務(wù)。
CompactDisc接口
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public interface CompactDisc { //播放某一個(gè)磁道中的歌曲 void playTrack(String track); } |
實(shí)現(xiàn)類(lèi)BlankDisc
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public class BlankDisc implements CompactDisc { private String title; private String artist; private List<String> tracks; public void setTitle(String title) { this.title = title; } public void setArtist(String artist) { this.artist = artist; } public void setTracks(List<String> tracks) { this.tracks = tracks; } @Override public void playTrack(String track) { System.out.println("-Track: " + track); } } |
切面類(lèi)TraceCount
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/** * 切面類(lèi)的任務(wù)：記錄每個(gè)磁道被播放的次數(shù) * Created by Administrator on 2017/12/1. */@Component@Aspectpublic class TrackCounter { private Map<String, Integer> trackCounts = new HashMap<>(); @Pointcut("execution(* chapter04.aop_args.BlankDisc.playTrack(String)) && args(track)") public void trackPlayed(String track) { } //在播放前，為該磁道計(jì)數(shù) @Before("trackPlayed(track)") public void countTrack(String track) { int currentCount = getPlayCount(track); trackCounts.put(track, currentCount + 1); } public int getPlayCount(String track) { return trackCounts.containsKey(track) ? trackCounts.get(track) : 0; } } |
applicationContext.xml配置文件
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<context:component-scan base-package="aop_test,chapter04"/> <bean id="compactDisc" class="chapter04.aop_args.BlankDisc"> <property name="title" value="Sgt. Pepper's Lonely Hearts Club Band" /> <property name="artist" value="The Beatles" /> <property name="tracks"> <list> <value>Sgt. Pepper's Lonely Hearts Club Band</value> <value>With a Little Help from My Friends</value> <value>Lucy in the Sky with Diamonds</value> <value>Getting Better</value> <value>Fixing a Hole</value> <value>She's Leaving Home</value> <value>Being for the Benefit of Mr. Kite!</value> <value>Within You Without You</value> <value>When I'm Sixty-Four</value> <value>Lovely Rita</value> <value>Good Morning Good Morning</value> <value>Sgt. Pepper's Lonely Hearts Club Band (Reprise)</value> <value>A Day in the Life</value> </list> </property> </bean> <!-- 開(kāi)啟aop注解 --><aop:aspectj-autoproxy/> |
測(cè)試
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@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration("classpath:applicationContext.xml") public class test_aop_args { @Autowired CompactDisc cd; @Autowired TrackCounter trackCounter; @Test public void test(){ cd.playTrack("Sgt. Pepper's Lonely Hearts Club Band"); cd.playTrack("With a Little Help from My Friends"); cd.playTrack("Lucy in the Sky with Diamonds"); cd.playTrack("Sgt. Pepper's Lonely Hearts Club Band"); cd.playTrack("With a Little Help from My Friends"); cd.playTrack("Sgt. Pepper's Lonely Hearts Club Band"); System.out.println(trackCounter.getPlayCount("Sgt. Pepper's Lonely Hearts Club Band")); System.out.println(trackCounter.getPlayCount("With a Little Help from My Friends")); System.out.println(trackCounter.getPlayCount("Lucy in the Sky with Diamonds")); System.out.println(trackCounter.getPlayCount("Getting Better")); } } |
測(cè)試結(jié)果 3，2，1，0
以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：http://blog.csdn.net/u013905744/article/details/78690027
