Tool usage summary

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Preface

Easy to find some excellent tool classes , Solve the problem of sudden brain short circuit .

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One 、 Tool class reference summary ：

Example ： Get the start time and end time of the year , Query the total number of orders in the whole year 、 Order amount ……

Java Get this week 、 This month, 、 This year 、 And tools for various time periods .link

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summary