本文介绍了详解spring切面使用传递给被通知方法的参数，分享给大家，具体如下：
场景：
BlankDisc代表CD实体，可以通过playTrack()方法直接播放某一个磁道中的歌曲。
需求是记录每个磁道被播放的次数。
一种方法就是修改playTrack()方法，直接在每次调用的时候记录这个数量。但是，记录磁道的播放次数与播放本身是不同的关注点，因此不应该属于playTrack()方法。这应该是切面要完成的任务。
CompactDisc接口
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public interface CompactDisc { //播放某一个磁道中的歌曲 void playTrack(String track); } |
实现类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); } } |
切面类TraceCount
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/** * 切面类的任务：记录每个磁道被播放的次数 * 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，为该磁道计数 @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> <!-- 开启aop注解 --><aop:aspectj-autoproxy/> |
测试
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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")); } } |
测试结果 3，2，1，0
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：http://blog.csdn.net/u013905744/article/details/78690027
