收到错误“需要一个类型的bean......无法找到”

Question

我已经制作了一个名为费用跟踪器的项目的基本结构，但我遇到了错误。尽管我已经尝试解决它很长时间了，但它仍然存在。

错误：

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应用程序无法启动

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描述：

com.app.expensetracker.service.CategoryServiceImpl 中的字段categoryRepository 需要类型为“com.app.expensetracker.dao.CategoryRepository”的 bean，但无法找到。

注入点有以下注释： - @org.springframework.beans.factory.annotation.Autowired（必需= true）

行动：

考虑在配置中定义“com.app.expensetracker.dao.CategoryRepository”类型的 bean。

类别控制器：

package com.app.expensetracker.controller;
import com.app.expensetracker.dto.CategoryCreateRequest;
import com.app.expensetracker.entity.Category;
import com.app.expensetracker.service.CategoryService;
import jakarta.validation.Valid;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import java.util.*;

@RestController
@RequestMapping("/category")
public class CategoryController {
    @Autowired
    private CategoryService categoryService;
    @PostMapping("/create")
    public  Category createCategory(@RequestBody @Valid CategoryCreateRequest categoryCreateRequest){
        return categoryService.createCategory(categoryCreateRequest);
    }
    @PutMapping("/update/{catId}")
    public Category updateCategory(@PathVariable("catId") String catId, @RequestBody @Valid CategoryCreateRequest categoryCreateRequest){
        return categoryService.updateCategory(catId, categoryCreateRequest);
    }
    @GetMapping("/get/{catId}")
    public ResponseEntity<Optional<Category>> getCategoryById(@PathVariable String catId) {
        return categoryService.getCategoryById(catId);
    }
    @PostMapping("/delete/{catId}")
    public ResponseEntity<Optional<Category>> deleteCategoryById(@PathVariable String catId) {
        return categoryService.deleteCategoryById(catId);
    }

}

类别存储库

package com.app.expensetracker.dao;

import com.app.expensetracker.entity.Category;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface CategoryRepository extends JpaRepository<Category, String> {

}

类别创建请求

package com.app.expensetracker.dto;
import com.app.expensetracker.entity.Category;
import jakarta.validation.constraints.NotBlank;
import jakarta.validation.constraints.Size;
import lombok.*;

import java.util.List;
import java.util.UUID;

@Getter
@Setter
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ToString
public class CategoryCreateRequest {
    @NotBlank
    private String categoryName;

    @Size(min=2,message="Enter 2 users only")
    private List<String> users;

    public Category to(){
        return Category.builder()
                .cat_id(UUID.randomUUID().toString())
                .categoryName(this.categoryName)
                .users(this.users)
                .build();
    }
}

类别

package com.app.expensetracker.entity;

import jakarta.persistence.*;
import lombok.*;
import java.util.List;

@Entity
@Table(name = "category")
@NoArgsConstructor
@AllArgsConstructor
@Getter
@Setter
@Builder
@ToString

public class Category {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name="cat_id",nullable = false)
    private String cat_id;

    @Column(name="categoryName")
    private String categoryName;

    @Column(name="users")
    private List<String> users;

//    @ManyToOne(cascade = CascadeType.ALL,fetch = FetchType.LAZY)
//    @JoinColumn(name = "user_id")
//    private  User user;

}

类别服务

package com.app.expensetracker.service;

import com.app.expensetracker.dto.CategoryCreateRequest;
import com.app.expensetracker.entity.Category;
import org.springframework.http.ResponseEntity;
import java.util.Optional;

public interface CategoryService {

    Category createCategory(CategoryCreateRequest categoryCreateRequest);
    ResponseEntity<Optional<Category>> getCategoryById(String category_id);
    Category updateCategory(String categoryId, CategoryCreateRequest categoryCreateRequest);
    ResponseEntity<Optional<Category>> deleteCategoryById(String category_id);
}

类别ServiceImpl

package com.app.expensetracker.service;
import com.app.expensetracker.dao.CategoryRepository;
import com.app.expensetracker.dto.CategoryCreateRequest;
import com.app.expensetracker.entity.Category;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.Optional;

@Service
public class CategoryServiceImpl implements CategoryService{
@Autowired
private CategoryRepository categoryRepository;

    @Override
    @Transactional
    public Category createCategory(CategoryCreateRequest categoryCreateRequest){
        Category category = categoryCreateRequest.to();
        return categoryRepository.save(category);
    }
    
    
    @Override
    @Transactional
    public ResponseEntity<Optional<Category>> getCategoryById(String category_id){
    
        Optional<Category> category =  categoryRepository.findById(category_id);
        if(category == null){
            return ResponseEntity.notFound().build();
        }
        else{
            return ResponseEntity.ok(category);
        }
    
    }
    
    @Override
    @Transactional
    public Category updateCategory(String categoryId, CategoryCreateRequest categoryCreateRequest){
        Category category = categoryCreateRequest.to();
        return categoryRepository.save(category);
    }
    
    @Override
    @Transactional
    public ResponseEntity<Optional<Category>> deleteCategoryById(String category_id){
        Optional<Category> category =  categoryRepository.findById(category_id);
        if(category == null){
            return ResponseEntity.notFound().build();
        }
        else{
            categoryRepository.deleteById(category_id);
            return ResponseEntity.ok(category);
        }
    }

}

费用追踪应用程序

package com.app.expensetracker;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication //(exclude = {DataSourceAutoConfiguration.class })
//@ComponentScan(basePackages = "com.app.*")
//@EntityScan("com.app.*")
@EnableJpaRepositories(basePackages = "com.app.expensetracker.repository")

public class ExpenseTrackerApplication {

    public static void main(String[] args) {

        SpringApplication.run(ExpenseTrackerApplication.class, args);
    }

}

Answer 1

我想问题来自于

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name="cat_id",nullable = false)
private String cat_id;

因为你正在使用

@GeneratedValue(strategy = GenerationType.AUTO)

在

String

字段上，它是错误的，因为

strategy = GenerationType.AUTO

：标识列、序列或表，具体取决于底层数据库，通常是

long

、

short

或

int

，而不是

String

。

要修复它，您必须对其进行类似的设置：

@Id
@GeneratedValue(generator = "uuid")
@GenericGenerator(name = "uuid", strategy = "uuid2")
@Column(name = "cat_id", nullable = false)
private String cat_id;