Record the time to read the file (the system cannot find the specified path)

Catalog

1： Write it at the front

2： The process

2.1： Environmental preparation

2.2： Result demonstration

2.3： improvement

3： summary

---

1： Write it at the front

We usually do projects , It must involve the reading of files , But there is such a situation occasionally , That is, the project is good when tested locally , Once packaged into jar package （ At present, the mainstream architecture generally uses microservices , Convenient and quick ） function , The file path cannot be found java.lang.RuntimeException: file\test.txt ( The system could not find the specified path .) Similar questions , A thorough analysis of the problems encountered by the author before .

2： The process

2.1： Environmental preparation

1： Create a springBoot project , Structure is shown in figure , among test.txt The content is casual

 

2：service structure

3：controller structure

 

2.2： Result demonstration

1： Start the project locally for testing , The result was perfect , You can read the file

 

2： So let's use maven The tool compiles the project , pack ---- > formation read_file-0.0.1-SNAPSHOT.jar

3： find jar Directory address

4： I tested it with windows System , Enter... Directly under the current directory cmd, perform cmd command （ This operation is an excellent one ）, Then a small black box pops up , The project started successfully

5： Next, let's continue to call the interface to get the file to see the results , The result is perfect and the result we want

 

2.3： improvement

1： This time we are reading the file , Use getResourceAsStream Read out

2： Local read succeeded , No problem

3： Back to the previous , Type the project as a jar Package to run , See if you can read . The same way as before .

4： Run this new jar, Still use the previous operation , To the current directory of the project , Input cmd function cmd Command line

5： test result , No report error , The description file has been read .

3： summary

Why use the former method , You can run locally , Just put it on the server , The reason is that this file does exist locally , Can directly File Class to read files , But once it's packaged , because springboot The project will be packaged into a jar package , Read jar What's in it , It is definitely not feasible to use the previous method of reading files , Want to read a jar What's inside , We can use class loaders ---> getResourceAsStream（path） The method provided by , Bear in mind , Bear in mind , Bear in mind .

The source code has been uploaded to Code cloud hosting Address ： https://gitee.com/zccpojo/read_file