介紹Querydsl Web Support實現REST Query Language

介紹Querydsl Web Support實現REST Query Language

文本我們討論sprin data Querydsl web支持功能。

Maven 依賴配置

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.0.RELEASE</version>
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-commons</artifactId>
    </dependency>
    <dependency>
        <groupId>com.mysema.querydsl</groupId>
        <artifactId>querydsl-apt</artifactId>
        <version>${querydsl.version}</version>
    </dependency>
    <dependency>
        <groupId>com.mysema.querydsl</groupId>
        <artifactId>querydsl-jpa</artifactId>
        <version>${querydsl.version}</version>
    </dependency>

QueryDsl web support 在spring-data-commons 1.11版本之後有效。

User Repository

先定義Repository：

public interface UserRepository extends
  JpaRepository<User, Long>, QueryDslPredicateExecutor<User>, QuerydslBinderCustomizer<QUser> {
    @Override
    default public void customize(QuerydslBindings bindings, QUser root) {
        bindings.bind(String.class).first(
          (StringPath path, String value) -> path.containsIgnoreCase(value));
        bindings.excluding(root.email);
    }
}

解釋：
- 我們重載QuerydslBinderCustomizer customize() 方法，自定義缺省binding。
- 默認爲相等比較，我們修改爲忽略大小寫比較。
- 並且從Predicate中排除用戶email。

讀者可以參見官方完整文檔。

User Controller

下面我們看User Controller：

@RequestMapping(method = RequestMethod.GET, value = "/users")
@ResponseBody
public Iterable<User> findAllByWebQuerydsl(
  @QuerydslPredicate(root = User.class) Predicate predicate) {
    return userRepository.findAll(predicate);
}

最有趣的是——我們直接從HTTPRequest中獲取Predicate，並指定@QuerydslPredicate註解。
測試UrL爲：

http://localhost:8080/users?firstName=john

返回數據結構：

[
   {
      "id":1,
      "firstName":"john",
      "lastName":"doe",
      "email":"[email protected]",
      "age":11
   }
]

實際測試

下面，我們進行完整的QueryDsl Web Support測試：

@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration(classes = Application.class)
@WebAppConfiguration
public class UserLiveTest {

    private ObjectMapper mapper = new ObjectMapper();
    private User userJohn = new User("john", "doe", "[email protected]");
    private User userTom = new User("tom", "doe", "[email protected]");

    private static boolean setupDataCreated = false;

    @Before
    public void setupData() throws JsonProcessingException {
        if (!setupDataCreated) {
            givenAuth().contentType(MediaType.APPLICATION_JSON_VALUE)
                       .body(mapper.writeValueAsString(userJohn))
                       .post("http://localhost:8080/users");

            givenAuth().contentType(MediaType.APPLICATION_JSON_VALUE)
                       .body(mapper.writeValueAsString(userTom))
                       .post("http://localhost:8080/users");
            setupDataCreated = true;
        }
    }

    private RequestSpecification givenAuth() {
        return RestAssured.given().auth().preemptive().basic("user1", "user1Pass");
    }
}

首先，獲取所有用戶：

@Test
public void whenGettingListOfUsers_thenCorrect() {
    Response response = givenAuth().get("http://localhost:8080/users");
    User[] result = response.as(User[].class);
    assertEquals(result.length, 2);
}

根據first name查詢用戶：

@Test
public void givenFirstName_whenGettingListOfUsers_thenCorrect() {
    Response response = givenAuth().get("http://localhost:8080/users?firstName=john");
    User[] result = response.as(User[].class);
    assertEquals(result.length, 1);
    assertEquals(result[0].getEmail(), userJohn.getEmail());
}

根據last name查詢用戶：

@Test
public void givenPartialLastName_whenGettingListOfUsers_thenCorrect() {
    Response response = givenAuth().get("http://localhost:8080/users?lastName=do");
    User[] result = response.as(User[].class);
    assertEquals(result.length, 2);
}

根據email查詢用戶：

@Test
public void givenEmail_whenGettingListOfUsers_thenIgnored() {
    Response response = givenAuth().get("http://localhost:8080/users?email=john");
    User[] result = response.as(User[].class);
    assertEquals(result.length, 2);
}

我們嘗試通過email查詢用戶時，查詢被忽略了，因爲prodicate中排除了email字段。

總結

本文快速介紹Spring Data Querydsl Web支持，很酷且簡單的方法可以直接從HTTP請求中獲得Predicate並檢索數據。