尝试使用Spring Boot在Redis缓存中插入数据时，出现一些运行时错误

Question

尝试通过Redis缓存检索数据时遇到以下错误：- 返回用于缓存操作的空键（也许您在没有调试信息的类上使用了命名的参数？）Builder [public java.util.List com.concretepage.CelebController.getAll（）] caches = [celebcache] | key ='＃p1'| keyGenerator =''| | cacheManager =''| | cacheResolver =''|条件=''|除非=''| sync ='false']的根本原因

已尝试通过将cachekey重命名为＃p0但仍然面临相同的错误来解决其他类似类型的问题。

型号：-

import javax.persistence.*;

@Entity(name="celeb")
public class Celeb {

    @Id
    @GeneratedValue(strategy= GenerationType.IDENTITY)
    private long id;
    @Column(name="celeb_name")
    private String name;
    @Column(name="no_of_followers")
    private long followers;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public long getFollowers() {
        return followers;
    }

    public void setFollowers(long followers) {
        this.followers = followers;
    }

    @Override
    public String toString() {
        return "Celeb{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", followers=" + followers +
                '}';
    }
}

模型控制器：-

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
public class CelebController {

    Logger logger = LoggerFactory.getLogger("CelebController");

    @Autowired
    private CelebRepository celebRepository;


    @PostMapping("/create")
    public void createUser(@RequestBody Celeb user) {
        celebRepository.save(user);
    }

    @Cacheable(value = "celebcache", key = "#p0")
    @GetMapping("/getall")
    public List<Celeb> getAll() {

        logger.info("Returning from DB");
        return celebRepository.findAll();

    }

    @PostMapping("/delete")
    public void createUser(@RequestParam(value = "userid")Integer id) {
        celebRepository.deleteById(id);
    }


}

Answer 1

正如您所指出的，尝试#p0和#p1无效。这是因为它将方法 parameters 引用到了方法...在您的情况下，其中没有一个！参见：

// #p0 and #p1 reference non-existing method parameters...
@Cacheable(value = "celebcache", key = "#p0") 
public List<Celeb> getAll(/* zero input parameters */) { ... }

对于每个the docs here，您完全不必指定key：

  

如果未提供任何参数，则返回SimpleKey.EMPTY

因此以下内容就足够了：

@Cacheable(value = "celebcache")