Spring-boot官方案例分析之data-jpa

Posted 2020-08-14

Spring-boot官方案例分析之data-jpa

package sample.data.jpa;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.test.context.ActiveProfiles;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.web.WebAppConfiguration;
import org.springframework.test.web.servlet.MockMvc;
import org.springframework.test.web.servlet.setup.MockMvcBuilders;
import org.springframework.web.context.WebApplicationContext;

import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;

/**
 * Integration test to run the application.
 *
 * @author Oliver Gierke
 */
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = SampleDataJpaApplication.class)
@WebAppConfiguration
@ActiveProfiles("scratch")
// Separate profile for web tests to avoid clashing databases
public class SampleDataJpaApplicationTests {

   @Autowired
   private WebApplicationContext context;

   private MockMvc mvc;

   @Before
   public void setUp() {
      this.mvc = MockMvcBuilders.webAppContextSetup(this.context).build();
   }

   @Test
   public void testHome() throws Exception {

      this.mvc.perform(get("/")).andExpect(status().isOk())
            .andExpect(content().string("Bath"));
   }
}

1. 首先测试类中选择了要使用的配置文件

@ActiveProfiles(“scratch”)

对应的properties为application-scratch.properties

内容为：

spring.datasource.url: jdbc:hsqldb:mem:scratchdb

定义了数据源的url；

@Autowired

private WebApplicationContext context;

注入应用上下文context；

定义MockMvc，然后@Before注解执行初始化容器

@Before

public void setUp() {

   

   this.mvc = MockMvcBuilders.webAppContextSetup(this.context).build();

}

 

然后模拟发送请求测试：

 

类图关系：

 

根据这个测试用例来走一遍请求处理过程：

this.mvc.perform(get("/")).andExpect(status().isOk())

      .andExpect(content().string("Bath"));

get请求处理：到SampleController

@Autowired

   private CityService cityService;



   @RequestMapping("/")

   @ResponseBody

   @Transactional(readOnly = true)

   public String helloWorld() {

      return this.cityService.getCity("Bath", "UK").getName();

   }

}

注入了CityService组件属性，事务类型为只读。

然后执行服务组件CityService中的getCity()方法；

并且传入参数name=”Bath”,country=”UK”，然后调用getname方法获取name值。

public interface CityService {



   Page<City> findCities(CitySearchCriteria criteria, Pageable pageable);



   City getCity(String name, String country);



   Page<HotelSummary> getHotels(City city, Pageable pageable);



}

该接口中定义了查询方法；

把返回值存在Page对象中

在实现类中，标记为组件并设置id=cityService；这样程序执行会找到impl类；

@Component("cityService")

@Transactional

class CityServiceImpl implements CityService {



   private final CityRepository cityRepository;



   private final HotelRepository hotelRepository;



   @Autowired

   public CityServiceImpl(CityRepository cityRepository, HotelRepository hotelRepository) {

      this.cityRepository = cityRepository;

      this.hotelRepository = hotelRepository;

   }



   @Override

   public Page<City> findCities(CitySearchCriteria criteria, Pageable pageable) {



      Assert.notNull(criteria, "Criteria must not be null");

      String name = criteria.getName();



      if (!StringUtils.hasLength(name)) {

         return this.cityRepository.findAll(null);

      }



      String country = "";

      int splitPos = name.lastIndexOf(",");



      if (splitPos >= 0) {

         country = name.substring(splitPos + 1);

         name = name.substring(0, splitPos);

      }



      return this.cityRepository

            .findByNameContainingAndCountryContainingAllIgnoringCase(name.trim(),

                  country.trim(), pageable);

   }



   @Override

   public City getCity(String name, String country) {

      Assert.notNull(name, "Name must not be null");

      Assert.notNull(country, "Country must not be null");

      return this.cityRepository.findByNameAndCountryAllIgnoringCase(name, country);

   }



   @Override

   public Page<HotelSummary> getHotels(City city, Pageable pageable) {

      Assert.notNull(city, "City must not be null");

      return this.hotelRepository.findByCity(city, pageable);

   }

}

由于执行的是事务操作所以要加上@Transactional

通过构造函数注入其他组件；

@Override

public City getCity(String name, String country) {

   Assert.notNull(name, "Name must not be null");

   Assert.notNull(country, "Country must not be null");

   return this.cityRepository.findByNameAndCountryAllIgnoringCase(name, country);

}

在该方法中进行断言判断是否为空，然后执行Dao查询；在jpa中会通过不同的关键字在接口中定义方法名来映射为sql查询语句，上面方法相当于select * from city c where name=”bath”  返回的是一个city对象，前提是name值唯一确定。