英文:
REST API: org.springframework.beans.factory.UnsatisfiedDependencyException:
问题
我正在构建一个 REST API，但似乎无法摆脱 org.springframework.beans.factory.UnsatisfiedDependencyException 错误，我在代码中找不到问题所在。我将会欣赏对此的新的洞察力。
附言：在这里使用了 mongo DB。
首先，完整的错误信息如下：
2020-05-04 01:16:31.468 WARN 14412
--- [ main] ConfigServletWebServerApplicationContext :
在上下文初始化过程中遇到异常 - 正在取消刷新尝试：
org.springframework.beans.factory.UnsatisfiedDependencyException:
创建 bean 时出错，bean 名称为 'productController'：
通过字段 'productService' 表达的不满足的依赖关系；
嵌套异常是 org.springframework.beans.factory.UnsatisfiedDependencyException：
创建 bean 时出错，bean 名称为 'productServiceImpl'：
通过字段 'productRepo' 表达的不满足的依赖关系；
嵌套异常是 org.springframework.beans.factory.BeanCreationException：
创建 bean 时出错，bean 名称为 'productRepo'：
初始化方法的调用失败；嵌套异常是 org.springframework.data.mapping.PropertyReferenceException：
找不到类型为 Product 的属性 id！
public class Product {
@Id
private int ProductId;
// 其他变量以及设置和获取方法
@Repository
public interface ProductRepo extends MongoRepository<Product, String> {
// 方法
}
public interface ProductService {
// 方法
}
@Service
public class ProductServiceImpl implements ProductService {
@Autowired
private ProductRepo productRepo;
// 实现部分
}
英文:
I am building a REST API and can't seem to get rid of the org.springframework.beans.factory.UnsatisfiedDependencyException, I can't spot the issue in this. I will appreciate a fresh insight into this.
p.s: Using mongo DB for this
first off the full error
2020-05-04 01:16:31.468 WARN 14412
--- [ main] ConfigServletWebServerApplicationContext :
Exception encountered during context initialization -
cancelling refresh attempt:
org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name 'productController':
Unsatisfied dependency expressed through field 'productService';
nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException:
Error creating bean with name 'productServiceImpl':
Unsatisfied dependency expressed through field 'productRepo';
nested exception is org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'productRepo':
Invocation of init method failed; nested exception is org.springframework.data.mapping.PropertyReferenceException:
No property id found for type Product!
public class Product {
@Id
private int ProductId;
// and other variables plus setters and getters
@Repository
public interface ProductRepo extends MongoRepository<Product, String> {
// methods
}
public interface ProductService {
// methods
}
@Service
public class ProductServiceImpl implements ProductService {
@Autowired
private ProductRepo productRepo;
// implementations
}
答案1
得分: 2
尝试按照以下方式更改 Product 类：
@Entity
public class Product {
@Id
private String productId; // MongoRepository<Product, String>;
// 方法
}
在 Product 类中，缺少 @Entity 注解，并且 productId 应该是一个 String，正如存储库中指定的一样。
或者，如果您想保持当前字段类型，可以更改为 extends MongoRepository<Product, Integer>。
无论如何，它们应该匹配。
英文:
Try changing the Product class as the following:
@Entity
public class Product {
@Id
private String productId; // MongoRepository<Product, String>
// methods
}
In the Product class the @Entity annotation is missing and the productId should be a String, as specified in the repository.
Or change to extends MongoRepository<Product, Integer> if you want to keep the current field type.
In any case, they should match.
答案2
得分: 0
确保你的 Spring 应用程序知道你的类位于哪里。
使用 @ComponentScan(basePackages = "com.package")。
另外，如果你的产品类是希望持久化的，请使用 @Entity 进行标记，这样 Spring 就会知道它并且会将其创建为一个 Bean。
用 @Service 标记你的接口 ProductService，这样 Spring 就会知道它的存在。
英文:
Make You That Your Spring Application Knows Where Your Classes Resides.
Use @ComponentScan(basePackages = "com.package").
Moreover If Your Product Class Is Something That You Want to Persist Mark It With @Entity So Spring Knows about It And Creates A Bean Out Of it.
Mark Your interface ProductService with @service, So that Spring Knows About it.
答案3
得分: 0
UnsatisfiedDependencyException:
Repository.java这个页面中，类似于@respository注解的类作为返回类型为null，而在optinal的附近使用了default关键字。
这个方法对我有用。
英文:
Unsatisfieddependencyexception:
Repository.java this page like @respository annotation class below being return type null and near optinal <> using default keyword
This method working me.
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