java热冷饭(1)
bigzhu
posted @ Nov 16, 2007 10:12:00 PM
in java
, 1255 阅读
因为工作需要,开始热java的冷饭,毕竟放了快2年没动了.开始看java core主要记录一些要点,包括以前忘记掉的.
- java程序的全部内容都必须放置在class中
- class命名规范:单词开头大些字母,多个单词则每个都开头大些,词与词之前无下划线.
- 源代码文件名必须与public class的名字相同, .java作为文件后缀.
- jdk 1.4之后,强制main方法必须被声明为public的
- 有boolean类型:false,true两个类型.注意1不代表true,0也不代表false
- final定义常量,static final定义一个类常量,类常量定义在最外层类中,那么类中所有方法都可以使用这个常量.
- java支持三元操作:condition?expression1:expression2 条件为真,则返回expression1,否则返回expression2; ps:其实这是个蛮好用的东西,但是不知道为什么我一直不喜欢,也很少用,也许每次在用或者代码里面看到它的时候,总是脑子要转个弯,要转化为if,反而没得直接看到if else来得自然,虽然更简洁一些.(3.5.2)
- 静态方法?? 不懂. jdk 5.0以后,调用Math方法,不必再添加前缀了,比如求平法:Math.sqrt()
Sep 29, 2022 01:19:15 AM
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