Spring Boot中的service层

spring Boot中的service层是业务逻辑层，负责处理业务需求，封装业务方法，调用dao层的数据操作1。service层一般是一个接口和一个实现类，用@Service注解标注实现类2。service层的接口可以在controller层中调用，实现数据的传递和处理。

一个service层的示例代码如下：

• 首先，需要定义一个service层接口，例如ProductService.java，用于声明业务方法，如增加、编辑、获取和删除产品。
• 然后，需要定义一个service层实现类，例如ProductServiceImpl.java，用@Service注解标注，并实现接口中的业务方法，调用dao层的数据操作。
• 最后，在controller层中，用@Autowired注解自动注入service层接口，并调用其方法，返回数据给客户端。

具体的代码如下：

ProductService.java

package com.tutorialspoint.demo.service;

import java.util.Collection;

import com.tutorialspoint.demo.model.Product;

publicinterfaceProductService {
    publicabstractvoidcreateProduct(Product product);
    publicabstractvoidupdateProduct(String id, Product product);
    publicabstractvoiddeleteProduct(String id);
    publicabstract Collection<Product> getProducts();
}

ProductServiceImpl.java

package com.tutorialspoint.demo.service;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Service;

import com.tutorialspoint.demo.model.Product;

@ServicepublicclassProductServiceImplimplementsProductService {
    privatestatic Map<String, Product> productRepo = newHashMap<>();
    static {
        Producthoney=newProduct();
        honey.setId("1");
        honey.setName("Honey");
        productRepo.put(honey.getId(), honey);

        Productalmond=newProduct();
        almond.setId("2");
        almond.setName("Almond");
        productRepo.put(almond.getId(), almond);
    }
    @OverridepublicvoidcreateProduct(Product product) {
        productRepo.put(product.getId(), product);
    }
    @OverridepublicvoidupdateProduct(String id, Product product) {
        productRepo.remove(id);
        product.setId(id);
        productRepo.put(id, product);
    }
    @OverridepublicvoiddeleteProduct(String id) {
        productRepo.remove(id);

    }
    @Overridepublic Collection<Product> getProducts() {
        return productRepo.values();
    }
}

ProductServiceController.java

package com.tutorialspoint.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.tutorialspoint.demo.model.Product;
import com.tutorialspoint.demo.service.ProductService;

@RestControllerpublicclassProductServiceController {
   @Autowired
   ProductService productService;
   @RequestMapping(value = "/products")public ResponseEntity<Object> getProduct() {
      returnnewResponseEntity<>(productService.getProducts(), HttpStatus.OK);
   }
   @RequestMapping(value = "/products/{id}", method = RequestMethod.PUT)public ResponseEntity<Object> updateProduct(@PathVariable("id") String id, @RequestBody Product product) {   
      productService.updateProduct(id, product);
      returnnewResponseEntity<>("Product is updated successsfully", HttpStatus.OK);
   }
   @RequestMapping(value = "/products/{id}", method = RequestMethod.DELETE)public ResponseEntity<Object> delete(@PathVariable("id") String id) {   
      productService.deleteProduct(id);
      returnnewResponseEntity<>("Product is deleted successsfully", HttpStatus.OK);
   }
   @RequestMapping(value = "/products", method = RequestMethod.POST)public ResponseEntity<Object> createProduct(@RequestBody Product product) {
      productService.createProduct(product);
      returnnewResponseEntity<>("Product is created successfully", HttpStatus.CREATED);
   }
}