应用mixin来记录bean属性的改变

使用mixin来记录bean属性的改变
先定义一个需要被introduce的interface
java 代码?

1. public?interface?EditAware?{??
2. ??
3. ????public?Object?getOldValue(String?propertyName);??
4. ??
5. ????public?boolean?isEdited(String?propertyName);??
6. ??
7. }??

1. import?org.aopalliance.intercept.MethodInvocation;??
2. import?org.apache.commons.beanutils.PropertyUtils;??
3. import?org.apache.commons.lang.StringUtils;??
4. import?org.springframework.aop.support.DelegatingIntroductionInterceptor;??
5. ??
6. public?class?EditAwareMixin?extends?DelegatingIntroductionInterceptor?implements??
7. ????????EditAware?{??
8. ??
9. ????private?transient?Map?map?=?new?HashMap();??
10. ??
11. ????public?Object?getOldValue(String?propertyName)?{??
12. ????????return?map.get(propertyName);??
13. ????}??
14. ??
15. ????public?boolean?isEdited(String?propertyName)?{??
16. ????????return?map.containsKey(propertyName);??
17. ????}??
18. ??
19. ????public?Object?invoke(MethodInvocation?invocation)?throws?Throwable?{??
20. ????????if?(invocation.getMethod().getName().indexOf("set")?==?0)?{??
21. ????????????Object?_this?=?invocation.getThis();??
22. ????????????String?propertyName?=?invocation.getMethod().getName().substring(3);??
23. ????????????propertyName?=?StringUtils.uncapitalize(propertyName);??
24. ????????????Object?oldValue?=?PropertyUtils.getProperty(_this,?propertyName);??
25. ????????????Object?newValue?=?invocation.getArguments()[0];??
26. ????????????if?(!isEquals(oldValue,?newValue))??
27. ????????????????map.put(propertyName,?oldValue);??
28. ????????}??
29. ????????return?super.invoke(invocation);??
30. ????}??
31. ??
32. ????public?static?boolean?isEquals(Object?oldValue,?Object?newValue)?{??
33. ????????if?(oldValue?==?null?&&?newValue?==?null)??
34. ????????????return?true;??
35. ????????if?(oldValue?!=?null)??
36. ????????????return?oldValue.equals(newValue);??
37. ????????else??
38. ????????????return?newValue.equals(oldValue);??
39. ????}??
40. }??

1. import?org.springframework.aop.framework.ProxyFactory;??
2. import?org.springframework.beans.BeanUtils;??
3. ??
4. public?class?Main?{??
5. ??
6. ????public?static?void?main(String[]?args)?{??
7. ????????User?u1?=?new?User("username1",?"password1");??
8. ????????User?u2?=?new?User("username2",?"password2");??
9. ????????ProxyFactory?pc?=?new?ProxyFactory();??
10. ????????pc.setProxyTargetClass(true);??
11. ????????pc.setTargetClass(u1.getClass());??
12. ????????pc.addAdvice(new?EditAwareMixin());??
13. ????????pc.setTarget(u1);??
14. ????????u1?=?(User)?pc.getProxy();??
15. ????????BeanUtils.copyProperties(u2,?u1);??
16. ????????EditAware?ea?=?(EditAware)?u1;??
17. ????????System.out.println(ea.isEdited("username"));??
18. ????????System.out.println(ea.getOldValue("username"));??
19. ????}??
20. ??
21. ????public?static?class?User?{??
22. ????????private?String?username;??
23. ????????private?String?password;??
24. ??
25. ????????public?User()?{??
26. ??
27. ????????}??
28. ??
29. ????????public?User(String?username,?String?password)?{??
30. ????????????this.username?=?username;??
31. ????????????this.password?=?password;??
32. ????????}??
33. ??
34. ????????public?String?getUsername()?{??
35. ????????????return?username;??
36. ????????}??
37. ??
38. ????????public?void?setUsername(String?username)?{??
39. ????????????this.username?=?username;??
40. ????????}??
41. ??
42. ????????public?String?getPassword()?{??
43. ????????????return?password;??
44. ????????}??
45. ??
46. ????????public?void?setPassword(String?password)?{??
47. ????????????this.password?=?password;??
48. ????????}??
49. ??
50. ????}??
51. }??