介绍Querydsl Web Support实现REST Query Language

文本我们讨论sprin data Querydsl web支持功能。

Maven 依赖配置

<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版本之后有效。

User Repository

先定义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); 
    } 
}

解释：
- 我们重载QuerydslBinderCustomizer customize() 方法，自定义缺省binding。
- 默认为相等比较，我们修改为忽略大小写比较。
- 并且从Predicate中排除用户email。

读者可以参见官方完整文档。

User Controller

下面我们看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——我们直接从HTTPRequest中获取Predicate，并指定@QuerydslPredicate注解。
测试UrL为：

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

返回数据结构：

[ 
   { 
      "id":1, 
      "firstName":"john", 
      "lastName":"doe", 
      "email":"john@test.com", 
      "age":11 
   } 
]

实际测试

下面，我们进行完整的QueryDsl Web Support测试：

@RunWith(SpringJUnit4ClassRunner.class) 
@SpringApplicationConfiguration(classes = Application.class) 
@WebAppConfiguration 
public class UserLiveTest {
    
 
    private ObjectMapper mapper = new ObjectMapper(); 
    private User userJohn = new User("john", "doe", "john@test.com"); 
    private User userTom = new User("tom", "doe", "tom@test.com"); 
 
    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，获取所有用户：

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

根据first name查询用户：

@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()); 
}

根据last name查询用户：

@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); 
}

根据email查询用户：

@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); 
}

我们尝试通过email查询用户时，查询被忽略了，因为prodicate中排除了email字段。

总结

本文快速介绍Spring Data Querydsl Web支持，很酷且简单的方法可以直接从HTTP请求中获得Predicate并检索数据。

本文参考链接：https://blog.csdn.net/neweastsun/article/details/80874220