Practice of online problem feedback module (12): realize image deletion function

author ：bug bacteria

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One 、 summary

        The next few issues ,bug I want to share with you that I just received a temporary demand yesterday , It's hot , I would like to share how I faced the temporary requirements and made the whole development cycle , It includes sorting out businesses, creating business tables, realizing business logic to form a closed loop, and connecting with the front end , Some business development and functional development will be interspersed , This one-stop process is witnessed online with you , Share with the novice , I hope it will help you .

Environmental statement ：idea2019.3 + springboot2.3.1.REALSE + mybati-plus3.2.0 + mysql5.6 + jdk1.8

        If the partners feel that the article is helpful to you in the process of reviewing the article , Please don't be stingy with your praise , Boldly put the article Lighten up Well , Your likes are three in a row ( Collection ️+ Focus on + Leaving a message. ) That's right bug The best encouragement and support on my creative path . Time does not give up ‍*️, Create constantly , come on. ️ 

Two 、 Text

        This issue , I then focus on the picture , Since we want to teach , It is necessary to complete the addition, deletion, modification and check of the pictures . So for you in the future , If there is any business related to pictures , Then you have no pressure , Follow my tutorial directly , I'll teach you hand in hand , This must be the fastest and best zero foundation introductory teaching , Maybe they will be appreciated by the leaders , Work , It's not just about code safety and efficiency , Get off work early , Try to finish the workload of the day within working hours , This is the goal of everyone , It's yours and mine , Let's cheer together ！ Ok or not ？

        Let's not talk more nonsense , Start today's content directly .

3、 ... and 、 How to code image deletion

        Speaking of the contents of these issues , Addition, deletion, modification and check of pictures , The only thing left is to delete the picture , We talked about the other three function points in the previous issues , For example, picture upload 、 Images are downloaded 、 Picture preview online , And this issue , Let's finish it , Put the rest of the specified deletion function of the picture to the implementation . This piece of picture business is closed-loop , You can upload to the server and delete the image resources of the server , Right .

        Talk about these small function points , Although it is not directly related to the business , But when it comes to business scenarios such as picture resources , The addition, deletion and modification of this picture are indispensable , So , I will tell you about these small function points word by word , I hope you will meet with this business in the future , If you can help .

        I don't say much nonsense , Let's begin today's lesson .

1️⃣ Definition Controller request

        We're still the same old way , Define the request interface first , The function node is image deletion , Those parameters are required ？ According to the business analysis, a wave can be obtained , I will tell you about my actual business scenario . For example, my business scenario is , Users can edit their own feedback , At the same time, you can manually delete the attached pictures , In other words, you can edit the contents of common fields , You can also remove attached pictures , Then I will separate this point , The picture needs to remove the direct call interface 1, Feedback problem editing call interface 2, Right , In this way, there is no need to organize the business into a complex business logic that is saved together with the problem feedback at that time .

        so, Let's go on , Let's go straight to the code ！

    @GetMapping("/delete-img-by-path")
    @ApiOperation(value = " Picture deletion ", notes = " Delete the picture according to the picture address ")
    public ResultResponse<Boolean> deleteImgByPath(@ApiParam(" Picture path ") @RequestParam("imgPath") String imgPath,
                                                   @ApiParam(" Domain account number of the feedback person id") @RequestParam("accountId") String accountId,
                                                   @ApiParam(" The primary key of this data id") @RequestParam("id") String id) {
        return userQuestionsService.deleteImgByPath(imgPath, accountId, id);
    }

2️⃣ Defining interfaces deleteImgByPath()

        The next step is to define the deleteImgByPath()  The interface . The specific implementation code is as follows ：

ResultResponse<Boolean> deleteImgByPath(String imgPath, String accountId,String id);

3️⃣ Realization deleteImgByPath() Method

        Here is the key point of image deletion , You should know the logic of batch saving my pictures , In the data filePaths Fields are saved with commas separated by multiple picture paths , So for the need to remove filePaths A path in , Then we need to delete the path, specify the path to be removed and update the record , That is, write the removed path back to the record .

        therefore , We write this method , First of all ： Update the removed path address , second ： Remove server files . The premise of running the second step is that the first step must be successful , Because the first step is more error prone , For the second step, even if the removal fails , You can also conduct a regular scan to clean up useless resources in the future , Even if deleting the file fails , That is, it takes up a little server memory resources , It doesn't affect anything , Because the user wants the removal to be successful , Therefore, the success rate of submission and removal , We just update the path first , Remove the entity file after .

        Then I will take you all to implement this method .

@Override
    public ResultResponse<Boolean> deleteImgByPath(String imgPath, String accountId, String id) {

        // First query this data 
        UserQuestionsEntity entity = this.getById(id);
        if (Objects.isNull(entity)) {
            return new ResultResponse<>(ErrorCodeEnum.DATA_NOT_EXIST);
        }

        // Remove the deleted path 
        String filePaths = entity.getFilePaths();
        if (StringUtils.isBlank(filePaths)) {
            return new ResultResponse<>(ErrorCodeEnum.FILE_NOT_FIND);
        }
        // Turn into str Array 
        String[] paths = filePaths.split(ConstantUtils.COMMA);
        // Remove the file path to delete 

        // First, determine whether the target path is in the specified set 
        boolean isExist = ReviewStringUtils.isExist(paths, imgPath);
        if (!isExist) {
            return new ResultResponse<>(ErrorCodeEnum.FILE_NOT_FIND);
        }
        String pathStr = ReviewStringUtils.removeStr(paths, imgPath);

        // Update the image path after removing the image 
        entity.setFilePaths(pathStr);

        // Update data 
        boolean success = this.updateById(entity);

        // If the update is successful, the file will be removed 
        if (success) {

            // Specify the delete target full path 
            String targetPath = this.buildImgPath(imgPath, accountId);
            uploader.removeFile(new File(targetPath));
            return new ResultResponse<>(success);
        }
        return new ResultResponse<>(ErrorCodeEnum.DELETE_IMAGE_ERROR);
    }

        Explain it. , about filePaths Field , We can directly use split Split with commas into an array of paths , Then match whether there is a target path from the array , Then select to return some business judgments about , For example, whether the file exists .

4️⃣ Realize the picture deleteImgByPath() Delete method

         For this removeFile() Method , This is a little bit easier , You can directly use file Provided by the delete() Method , The picture resource can be effectively deleted . This is very convenient and advantageous .

    public Boolean removeFile(File file) {

        // Delete directly 
        return file.delete();
    }

5️⃣ The interface test

         As for the above interfaces, they are all defined and implemented , So the remaining thing to do now is , unit testing + The interface test . We are more concerned about whether the function node can really meet the business needs , If the business needs cannot be reached , Then we have to modify or rewrite , It's possible , So when we finish writing an interface , Be sure to do a good test , Don't let other colleagues, such as testers 、 Front end personnel create extra workload .

         We can go directly online swagger Document or postman Debug the interface .

postman Test file delete interface

This is a nonexistent file path that I can pass , Deleting must be a direct return to customization msg.

         I give a path address to exist , Delete pictures . The demonstration results are as follows ：

         as for swagger file , The same operation demonstration , I'm not going to show you one by one . If you are not clear, you can ask in the comment area , I must have answered it at the first time .

6️⃣ summary

        Relatively speaking , It's still one step , Nothing happened bug, This measurement function is available , You can rest assured copy Ha .

 ... ...

        All right. , The above is all about this issue , Have you learned to give up ？ If it helps you , Please don't forget to give bug bacteria [ Three companies support ] yo . If you want to get more learning resources or want to communicate with more technology enthusiasts , You can pay attention to my official account. 『 Ape circle wonderful house 』, The backstage replies the key words to get the learning materials 、 Big factory surface 、 Interview templates and other massive resources , Just wait for you to get .

Four 、 I recommend

        For the actual development of the problem feedback module , I combed the teaching and link address of each issue completely , For reference only ： I hope it can help you .

• Practice of online problem feedback module ( One ): Sort out business requirements and create database tables
• Practice of online problem feedback module ( Two ): Encapsulate code to automatically generate class file
• Practice of online problem feedback module ( 3、 ... and ): Automatically generate all Controller、Service、Mapper Wait for the documents
• Practice of online problem feedback module ( Four ): Encapsulate generic field classes
• Practice of online problem feedback module ( 5、 ... and ): Realize the automatic filling function of general field content
• Practice of online problem feedback module ( 6、 ... and ): Interface document definition
• Practice of online problem feedback module ( 7、 ... and ): Installation and deployment swagger2
• ​ Practice of online problem feedback module ( 8、 ... and )​: Realize image upload function ( On )
• ​ Practice of online problem feedback module ( Nine )​: Realize image upload function ( Next )
• ​ Practice of online problem feedback module ( Ten )​: Realize the picture preview function
• ​ Practice of online problem feedback module ( 11、 ... and )​: Realize the picture download function
• ​ Practice of online problem feedback module ( Twelve )​: Realize the function of deleting pictures
• ​ Practice of online problem feedback module ( 13、 ... and )​: Realize multi parameter paging query list
• Practice of online problem feedback module ( fourteen ): Realize the online question answering function
• Practice of online problem feedback module ( 15、 ... and )​: Realize the function of online updating feedback status
• Practice of online problem feedback module ( sixteen )​: Realize the function of checking details
• Practice of online problem feedback module ( seventeen ): Realization excel Template online download function
• Practice of online problem feedback module ( eighteen ): Realization excel Batch import function of account file records
• Practice of online problem feedback module ( nineteen ): Realize batch export of data to excel Function in file
• Practice of online problem feedback module ( twenty ): Conclusion

        The above is the content of 20 issues , Each issue is dry , For the development of a module , How to build and test the deployment online bit by bit , I'll say it again , This is not an exercise , It's actual combat ！ It's actual combat ！ It's actual combat ！

         If you think you just need to understand one of the knowledge points or business , No objection , Just choose a few of them to study , It's all over anyway ; I just hope you can gain something , Grow up , It's not in vain for me to summarize and update you after work every day .

5、 ... and 、 At the end of the article

         If you want to learn more , Little friends can pay attention to bug I created a special column for you 《springboot Zero basic introductory teaching 》, It's all my hands , Ongoing update , I hope I can help more friends .

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【 Developing the cloud 】 It's a discount every year , You don't have to go around collecting sheep

        I am a bug bacteria , A procedural ape who wants to get out of the mountain and change his fate . There's a long way to go , Are waiting for us to break through 、 To challenge . Come on , friends , Let's cheer together ！ The future can be expected ,fighting！

         Finally, I'll give you two words I like very much , Share with you ！

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You can change... From now on , It can be the same , This matter , There are no rules , You can live your best .

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