????Java?????NullPointerException??????????
???????????? ???????[ 2014/10/22 14:01:26 ] ????????Java ???
????4) ?????????з???????????????collection????????顣
???????Java???????????Joshua Bloch????????Effective Java????????????????????????????Java??????ɡ?????????????collection????????飬???????????????size()??length()???????????????????????Collections???????????List??Set??Map: Collections.EMPTY_LIST??Collections.EMPTY_SET??Collections.EMPTY_MAP?????????????
????public List getOrders(Customer customer){
????List result = Collections.EMPTY_LIST;
????return result;
????}
????????????????Collections.EMPTY_SET??Collections.EMPTY_MAP??????????
????5) ???annotation@NotNull ?? @Nullable
??????д??????????????????????????????????@NotNull??@Nullable????annotation??????????????????????????????????????IDE?????????????annotation???????????????????飬?????????????????????????????????顣IntelliJ??findbugs??????????Щannotation????Щannotation?????JSR 305??????????????IDE????????У????annotation???????????????????@NotNull??@Nullable????????????????????????????顣???????????????Java??????????????£???????????????
????6) ???????????в??????????????????????
??????????????紴????????????????wrapper???????null?????????????????????????????????person??????е綽??????????null?????′????????????????????
????Person ram = new Person("ram");
????int phone = ram.getPhone();
???????????????????????????????????????< > ?????????????????????????????????????????Java?е????????????????塣
????7) ???Contract????????????????
??????Java?б????????????????????????????contract????????????????????????????????ò?????????????????????δ?????е??????????????????????????????????????Щ?????????????????????????????????????????????????????????????????????????????????????????????????Employee???????????????????id??name??????????е綽??????????????????Employee??е綽?????????????????????????0???????淵??null?????????????????????????????????Ч??????????????????????????????null?????????null?????????????????????????failing fast?????null????????????????????????????????????
????8)??????????е????????????
??????????????????????????????????????Customers??Orders ????????????????????????????????????????????????л??????????????????????????????????????????????????????null??????????????????Java?????е??????顣??????????м??????????????????????Щ?????????null???????Щ?????????????????в??????!= null????????
????9) ???????????Null Object Pattern??
????????????????????Java?е???????????????????????????????????????Щ??????????Collection.iterator()????????????????????????б??????????????????????????κε???????????????????Null object??????null?????????????????????????????????????в???????塣???????????????????hasNext()????false???????????????????????????Container??Collection??????????????У??????????????????null??????????
???????????????????????漰???????????????????SPASVOС??(021-61079698-8054)?????????????????????????
??????
Java???????????Щ???????????????Java????????????????Java?б???Map????????Java Web???????????????Java??????????????д?????Java????????7???????????????????????(java .net ?????)???Java??????????Python??????Java webdriver??λ????????′????е?????Java??д??????????????????Java???????????????JavaScript????????????Java?????????????????? Java???????10??????????????Java?м????????????????java???????ü???????????м???????????????????
???·???
??????????????????
2023/3/23 14:23:39???д?ò??????????
2023/3/22 16:17:39????????????????????Щ??
2022/6/14 16:14:27??????????????????????????
2021/10/18 15:37:44???????????????
2021/9/17 15:19:29???·???????·
2021/9/14 15:42:25?????????????
2021/5/28 17:25:47??????APP??????????
2021/5/8 17:01:11????????
?????????App Bug???????????????????????Jmeter?????????QC??????APP????????????????app?????е????????jenkins+testng+ant+webdriver??????????????JMeter????HTTP???????Selenium 2.0 WebDriver ??????