Spring Data ExampleMatchers by Example 返回空数组

Question

What I want is to filter and search for sheet music with Examplematcher and Examples from Spring. This is not going so smoothly as I thought. I hope you know what the solution is because I am stuck on it. It is a spring boot application.

Below my endpoint to filter:

   @GetMapping("/sheetmusic/filter")
    public List<SheetMusic> getSheetMusicByFilter(@RequestBody Map<String,String> body){
        String componist = body.get("componist");
        String key = body.get("key");
        String instrument = body.get("instrument");

        SheetMusic sheetMusic = new SheetMusic(componist,key,instrument);
        ExampleMatcher matcher = ExampleMatcher.matching()
                .withMatcher("componist", new ExampleMatcher.GenericPropertyMatcher().exact())
                .withMatcher("key",new ExampleMatcher.GenericPropertyMatcher().exact())
                .withMatcher("instrument",new ExampleMatcher.GenericPropertyMatcher().exact());

        Example<SheetMusic> example = Example.of(sheetMusic, matcher);
        List<SheetMusic> sheetMusics = sheetMusicRepository.findAll(example);
        return sheetMusics;

    }

The problem is that the list of sheetMusics is empty, I am 100% sure I have a sheetmusic in the database with a componist name as : 'Alan Walker' but it still returns nothing.

Answer 1

Try this

  ExampleMatcher matcher = ExampleMatcher.matching()
                .withMatcher("componist", exact())
                .withMatcher("key", exact())
                .withMatcher("instrument",exact());