初入spring boot（八 ）Spring Data REST

　　1. 什么是Spring Data REST

　　Spring Data JPA是基於Spring Data 的Repository之上，可以將Repository自動輸出為REST資源。目前Spring Data REST支持將Spring Data JPA、Spring Data MongoDB、Spring Data Neo4j、Spring Data Gemfire以及Spring Data Cassandra的Repository自動轉換成REST服務。

　　2. Spring mvc中配置使用Spring Data REST

　　Spring Data REST的配置是定義在RepositoryRestMvcConfiguration配置類中已經配置好了，我們可以通過繼承此類或者直接在自己的配置類上@Import此配置類

　　3. Spring boot的支持　　

　　Spring Boot對Spring Data REST的自動配置放置在rest包中

通過SpringBootRestConfiguration類的源碼我們可以得出，Spring Boot已經為我們自動配置了RepositoryRestConfiguration，所以在Spring boot中使用Spring Data REST只需引入spring-boot-starter-data-rest的依賴，無須任何配置即可使用。

Spring boot通過在application.properties中配置以“spring.data.rest”為前綴的屬性來配置RepositoryRestConfiguration

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.annotation.Order;
import org.springframework.data.rest.core.config.RepositoryRestConfiguration;
import org.springframework.data.rest.webmvc.config.RepositoryRestConfigurerAdapter;
import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;

@Order(0)
class SpringBootRepositoryRestConfigurer extends RepositoryRestConfigurerAdapter {

    @Autowired(required = false)
    private Jackson2ObjectMapperBuilder objectMapperBuilder;

    @Autowired
    private RepositoryRestProperties properties;

    @Override
    public void configureRepositoryRestConfiguration(RepositoryRestConfiguration config) {
        this.properties.applyTo(config);
    }

    @Override
    public void configureJacksonObjectMapper(ObjectMapper objectMapper) {
        if (this.objectMapperBuilder != null) {
            this.objectMapperBuilder.configure(objectMapper);
        }
    }

}

@ConfigurationProperties(prefix = "spring.data.rest")
public class RepositoryRestProperties {

    /**
     * Base path to be used by Spring Data REST to expose repository resources.
     */
    private String basePath;

    /**
     * Default size of pages.
     */
    private Integer defaultPageSize;

    /**
     * Maximum size of pages.
     */
    private Integer maxPageSize;

    /**
     * Name of the URL query string parameter that indicates what page to return.
     */
    private String pageParamName;

    /**
     * Name of the URL query string parameter that indicates how many results to return at
     * once.
     */
    private String limitParamName;

    /**
     * Name of the URL query string parameter that indicates what direction to sort
     * results.
     */
    private String sortParamName;

    /**
     * Strategy to use to determine which repositories get exposed.
     */
    private RepositoryDetectionStrategies detectionStrategy = RepositoryDetectionStrategies.DEFAULT;

    /**
     * Content type to use as a default when none is specified.
     */
    private MediaType defaultMediaType;

    /**
     * Return a response body after creating an entity.
     */
    private Boolean returnBodyOnCreate;

    /**
     * Return a response body after updating an entity.
     */
    private Boolean returnBodyOnUpdate;

    /**
     * Enable enum value translation via the Spring Data REST default resource bundle.
     * Will use the fully qualified enum name as key.
     */
    private Boolean enableEnumTranslation;

    public String getBasePath() {
        return this.basePath;
    }

    public void setBasePath(String basePath) {
        this.basePath = basePath;
    }

    public Integer getDefaultPageSize() {
        return this.defaultPageSize;
    }

    public void setDefaultPageSize(Integer defaultPageSize) {
        this.defaultPageSize = defaultPageSize;
    }

    public Integer getMaxPageSize() {
        return this.maxPageSize;
    }

    public void setMaxPageSize(Integer maxPageSize) {
        this.maxPageSize = maxPageSize;
    }

    public String getPageParamName() {
        return this.pageParamName;
    }

    public void setPageParamName(String pageParamName) {
        this.pageParamName = pageParamName;
    }

    public String getLimitParamName() {
        return this.limitParamName;
    }

    public void setLimitParamName(String limitParamName) {
        this.limitParamName = limitParamName;
    }

    public String getSortParamName() {
        return this.sortParamName;
    }

    public void setSortParamName(String sortParamName) {
        this.sortParamName = sortParamName;
    }

    public RepositoryDetectionStrategies getDetectionStrategy() {
        return this.detectionStrategy;
    }

    public void setDetectionStrategy(RepositoryDetectionStrategies detectionStrategy) {
        this.detectionStrategy = detectionStrategy;
    }

    public MediaType getDefaultMediaType() {
        return this.defaultMediaType;
    }

    public void setDefaultMediaType(MediaType defaultMediaType) {
        this.defaultMediaType = defaultMediaType;
    }

    public Boolean getReturnBodyOnCreate() {
        return this.returnBodyOnCreate;
    }

    public void setReturnBodyOnCreate(Boolean returnBodyOnCreate) {
        this.returnBodyOnCreate = returnBodyOnCreate;
    }

    public Boolean getReturnBodyOnUpdate() {
        return this.returnBodyOnUpdate;
    }

    public void setReturnBodyOnUpdate(Boolean returnBodyOnUpdate) {
        this.returnBodyOnUpdate = returnBodyOnUpdate;
    }

    public Boolean getEnableEnumTranslation() {
        return this.enableEnumTranslation;
    }

    public void setEnableEnumTranslation(Boolean enableEnumTranslation) {
        this.enableEnumTranslation = enableEnumTranslation;
    }

    public void applyTo(RepositoryRestConfiguration configuration) {
        if (this.basePath != null) {
            configuration.setBasePath(this.basePath);
        }
        if (this.defaultPageSize != null) {
            configuration.setDefaultPageSize(this.defaultPageSize);
        }
        if (this.maxPageSize != null) {
            configuration.setMaxPageSize(this.maxPageSize);
        }
        if (this.pageParamName != null) {
            configuration.setPageParamName(this.pageParamName);
        }
        if (this.limitParamName != null) {
            configuration.setLimitParamName(this.limitParamName);
        }
        if (this.sortParamName != null) {
            configuration.setSortParamName(this.sortParamName);
        }
        if (this.detectionStrategy != null) {
            configuration.setRepositoryDetectionStrategy(this.detectionStrategy);
        }
        if (this.defaultMediaType != null) {
            configuration.setDefaultMediaType(this.defaultMediaType);
        }
        if (this.returnBodyOnCreate != null) {
            configuration.setReturnBodyOnCreate(this.returnBodyOnCreate);
        }
        if (this.returnBodyOnUpdate != null) {
            configuration.setReturnBodyOnUpdate(this.returnBodyOnUpdate);
        }
        if (this.enableEnumTranslation != null) {
            configuration.setEnableEnumTranslation(this.enableEnumTranslation);
        }
    }

}

 

 

實戰演練

1.定義實體類

2.定義Repository

3.測試

@Entity
public class Person {
    @Id 
    @GeneratedValue
    private Long id;
    
    private String name;
    
    private Integer age;
    
    private String address;
    
    
    
    public Person() {
        super();
    }
    public Person(Long id, String name, Integer age, String address) {
        super();
        this.id = id;
        this.name = name;
        this.age = age;
        this.address = address;
    }
    public Long getId() {
        return id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }


}

public interface PersonRepository extends JpaRepository<Person, Long> {
    
    Person findByNameStartsWith(@Param("name")String name);
}

 

GET請求

　　http://localhost:8080/psersons　　　　獲取列表

　　http://localhost:8080/1　　　　　　　　獲取id為1的對象

　　在上面的自定義Repository中定義了findByNameStartsWith方法，若想此方法也暴露為REST資源，需做如下修改

public interface PersonRepository extends JpaRepository<Person, Long> {
    
    @RestResource(path = "nameStartsWith", rel = "nameStartsWith")
    Person findByNameStartsWith(@Param("name")String name);
}

此時使用GET訪問http://localhost:8080/persons/search/nameStartsWith?name=kevin,可實現查詢操作

　　http://localhost:8080/persons/?page=1&size=2　　　　分頁查詢，page-1即第2頁，size=2即每頁數量為2

　　http://localhost:8080/persons/?sort=age,desc　　　　  排序，即按照age屬性倒序

 

POST請求

　　http://localhost:8080/persons ,並將數據放到請求體中　　　　　　保存

　　http://localhost:8080/persons/21,並將數據放到請求體中　　　　  更新

 

DELETE請求

　　http://localhost:8080/persons/21    　　　　　　　　　　　　　 刪除

 

 

4. 定制

　　（1）定制根路徑

　　在上面的實戰例子中，我們訪問的REST資源的路徑是在根目錄下的，即http://localhost:8080/persos，如果我們需要定制根路徑的話，只需要在Spring Boot的application.properties中添加定義 spring.data.rest.base-path= /api 此時REST資源的路徑變成了http://localhost:8080/api/persons

　　（2）定制節點路徑

　　上例實戰中，我們的節點路徑為http://localhost:8080/persons，這是Spring Data REST的默認規則，就是在實體類之后加“s”來形成路徑。如果要對映射的名稱進行修改的話，需要在實體類Repository上使用@RepositoryRestResource注解的path屬性進行修改

@RepositoryRestResource(path = "people")
public interface PersonRepository extends JpaRepository<Person, Long> {
    
    @RestResource(path = "nameStartsWith", rel = "nameStartsWith")
    Person findByNameStartsWith(@Param("name")String name);

}

此時訪問REST服務的地址變成http://localhost:8080/api/people