常用

1. 异常

   • UnsupportedOperationException

2. 日志

   log.info(LogUtils.gen("message", "key1", value1, "key2", value2));
   log.info(LogUtils.gen("getUser", ImmutableMap.<String, String> builder().put("token", token).put("userId", userId).build()));
   

3. 对象克隆

   // 一般是从parent克隆出child
   BeanUtils.copyProperties(parent, child);
   

4. 线程

   new Thread(new Runnable() {
                @Override
                public void run() {
                    // code here
                    }
                }
            }).start();
   

5. 模板函数

   public <T> void test(T t1) {} // 函数定义
   test(new ClassA()); // 调用
   

6. 回调函数（Java8的功能）

   public void callbackUsage(Function<String, String> fn) {
    fn.apply(“123”);
   }
   this.callbackUsage(new Function<String, String>() {
    @Override
    public String apply(String t) {
        return null;
    }
   });
   

7. 注解类获取

   this.getClass().isAnnotationPresent(BizApi.class); // 获取所有引用的判断：BizApi是annotation
   

8. bean获取

this.service = this.context.getBean(IUserAccountService.class);

for (Map.Entry<String, Object> entry : this.context.getBeansWithAnnotation(BizApi.class).entrySet()) {
            this.apiMap.put(entry.getKey(), (IBizApi) entry.getValue());
}

文件系统

1. 组合路径

   Path path = Paths.get("path1",  "path2", "fileName");
   File file = path.toFile();