Spring Boot集成olingo快速入门demo

1.什么是olingo？

Apache Olingo 是个 Java 库，用来实现 Open Data Protocol (OData)。 Apache Olingo 包括服务客户端和 OData 服务器方面。

Open Data Protocol （开放数据协议，OData）

是用来查询和更新数据的一种Web协议，其提供了把存在于应用程序中的数据暴露出来的方式。OData运用且构建于很多 Web技术之上，比如HTTP、Atom Publishing Protocol（AtomPub）和JSON，提供了从各种应用程序、服务和存储库中访问信息的能力。OData被用来从各种数据源中暴露和访问信息， 这些数据源包括但不限于：关系数据库、文件系统、内容管理系统和传统Web站点。

2.代码工程

实验目标

利用olingo实现oData协议

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springboot-demo</artifactId>
        <groupId>com.et</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>olingo</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.olingo</groupId>
            <artifactId>olingo-odata2-core</artifactId>
            <version>2.0.11</version>
            <exclusions>
                <exclusion>
                    <groupId>javax.ws.rs</groupId>
                    <artifactId>javax.ws.rs-api</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.apache.olingo</groupId>
            <artifactId>olingo-odata2-jpa-processor-core</artifactId>
            <version>2.0.11</version>
        </dependency>
        <dependency>
            <groupId>org.apache.olingo</groupId>
            <artifactId>olingo-odata2-jpa-processor-ref</artifactId>
            <version>2.0.11</version>
            <exclusions>
                <exclusion>
                    <groupId>org.eclipse.persistence</groupId>
                    <artifactId>eclipselink</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jersey</artifactId>
        </dependency>


    </dependencies>
    <profiles>
        <profile>
            <id>local</id>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
            <properties>
                <activatedProperties>local</activatedProperties>
            </properties>
            <dependencies>
                <dependency>
                    <groupId>com.h2database</groupId>
                    <artifactId>h2</artifactId>
                    <scope>runtime</scope>
                </dependency>
            </dependencies>
        </profile>

        <profile>
            <id>cloud</id>
            <activation>
                <activeByDefault>false</activeByDefault>
            </activation>
            <properties>
                <activatedProperties>cloud</activatedProperties>
            </properties>
        </profile>
    </profiles>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

config

package com.et.olingo.config;

import com.et.olingo.service.OdataJpaServiceFactory;
import org.apache.olingo.odata2.api.ODataServiceFactory;
import org.apache.olingo.odata2.core.rest.ODataRootLocator;
import org.apache.olingo.odata2.core.rest.app.ODataApplication;
import org.glassfish.jersey.server.ResourceConfig;
import org.springframework.stereotype.Component;

import javax.inject.Inject;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.Path;
import javax.ws.rs.container.ContainerRequestContext;
import javax.ws.rs.container.ContainerRequestFilter;
import javax.ws.rs.container.ContainerResponseContext;
import javax.ws.rs.container.ContainerResponseFilter;
import javax.ws.rs.core.Context;
import javax.ws.rs.ext.Provider;
import java.io.IOException;

@Component
@ApplicationPath("/odata")
public class JerseyConfig extends ResourceConfig {

    public JerseyConfig(OdataJpaServiceFactory serviceFactory, EntityManagerFactory entityManagerFactory) {
        ODataApplication oDataApplication = new ODataApplication();
        oDataApplication
                .getClasses()
                .forEach( c -> {
                    if ( !ODataRootLocator.class.isAssignableFrom(c)) {
                        register(c);
                    }
                });
        register(new ODataServiceRootLocator(serviceFactory));
        register(new EntityManagerFilter(entityManagerFactory));
    }

    @Path("/")
    public static class ODataServiceRootLocator extends ODataRootLocator {

        private OdataJpaServiceFactory serviceFactory;

        @Inject
        public ODataServiceRootLocator (OdataJpaServiceFactory serviceFactory) {
            this.serviceFactory = serviceFactory;
        }

        @Override
        public ODataServiceFactory getServiceFactory() {
            return this.serviceFactory;
        }
    }

    @Provider
    public static class EntityManagerFilter implements ContainerRequestFilter,
            ContainerResponseFilter {
        public static final String EM_REQUEST_ATTRIBUTE =
                EntityManagerFilter.class.getName() + "_ENTITY_MANAGER";
        private final EntityManagerFactory entityManagerFactory;

        @Context
        private HttpServletRequest httpRequest;
        public EntityManagerFilter(EntityManagerFactory entityManagerFactory) {
            this.entityManagerFactory = entityManagerFactory;
        }

        @Override
        public void filter(ContainerRequestContext containerRequestContext) throws IOException {
            EntityManager entityManager = this.entityManagerFactory.createEntityManager();
            httpRequest.setAttribute(EM_REQUEST_ATTRIBUTE, entityManager);
            if (!"GET".equalsIgnoreCase(containerRequestContext.getMethod())) {
                entityManager.getTransaction().begin();
            }
        }
        @Override
        public void filter(ContainerRequestContext requestContext,
                           ContainerResponseContext responseContext) throws IOException {
            EntityManager entityManager = (EntityManager) httpRequest.getAttribute(EM_REQUEST_ATTRIBUTE);
            if (!"GET".equalsIgnoreCase(requestContext.getMethod())) {
                EntityTransaction entityTransaction = entityManager.getTransaction(); //we do not commit because it's just a READ
                if (entityTransaction.isActive() && !entityTransaction.getRollbackOnly()) {
                    entityTransaction.commit();
                }
            }
            entityManager.close();
        }
    }

}

controller

package com.et.olingo.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

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

@RestController
public class HelloWorldController {
    @RequestMapping("/hello")
    public Map<String, Object> showHelloWorld(){
        Map<String, Object> map = new HashMap<>();
        map.put("msg", "HelloWorld");
        return map;
    }
}

entity

service

package com.et.olingo.service;

import com.et.olingo.entity.Child;
import org.apache.olingo.odata2.api.edm.EdmException;
import org.apache.olingo.odata2.api.ep.EntityProviderException;
import org.apache.olingo.odata2.api.exception.ODataException;
import org.apache.olingo.odata2.api.exception.ODataNotFoundException;
import org.apache.olingo.odata2.api.processor.ODataResponse;
import org.apache.olingo.odata2.api.uri.info.*;
import org.apache.olingo.odata2.jpa.processor.api.ODataJPAContext;
import org.apache.olingo.odata2.jpa.processor.api.ODataJPADefaultProcessor;
import org.apache.olingo.odata2.jpa.processor.api.exception.ODataJPAModelException;
import org.apache.olingo.odata2.jpa.processor.api.exception.ODataJPARuntimeException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.InputStream;
import java.util.List;

public class CustomODataJpaProcessor extends ODataJPADefaultProcessor {

    private Logger logger = LoggerFactory.getLogger(getClass());

    public CustomODataJpaProcessor(ODataJPAContext oDataJPAContext) {
        super(oDataJPAContext);
    }

    @Override
    public ODataResponse readEntitySet(final GetEntitySetUriInfo uriParserResultView, final String contentType) throws ODataJPAModelException, ODataJPARuntimeException, EdmException {
        logger.info("READ: Entity Set {} called", uriParserResultView.getTargetEntitySet().getName());
        try {
            List<Object> jpaEntities = jpaProcessor.process(uriParserResultView);
            return responseBuilder.build(uriParserResultView, jpaEntities, contentType);
        } finally {
            this.close();
        }
    }

    @Override
    public ODataResponse readEntity(final GetEntityUriInfo uriParserResultView, final String contentType) throws ODataJPAModelException, ODataJPARuntimeException, ODataNotFoundException, EdmException {
        ODataResponse response = null;
        if (uriParserResultView.getKeyPredicates().size() > 1) {
            logger.info("READ: Entity {} called with key {} and key {}", uriParserResultView.getTargetEntitySet().getName(), uriParserResultView.getKeyPredicates().get(0).getLiteral(), uriParserResultView.getKeyPredicates().get(1).getLiteral());
        } else {
            logger.info("READ: Entity {} called with key {}", uriParserResultView.getTargetEntitySet().getName(), uriParserResultView.getKeyPredicates().get(0).getLiteral());
        }
        try {
            Object readEntity = jpaProcessor.process(uriParserResultView);
            response = responseBuilder.build(uriParserResultView, readEntity, contentType);
        } finally {
            this.close();
        }
        return response;
    }

    @Override
    public ODataResponse createEntity(final PostUriInfo uriParserResultView, final InputStream content, final String requestContentType, final String contentType) throws ODataJPAModelException, ODataJPARuntimeException, ODataNotFoundException, EdmException, EntityProviderException {
        logger.info("POST: Entity {} called", uriParserResultView.getTargetEntitySet().getName());
        ODataResponse response = null;
        try {
            Object createdEntity = jpaProcessor.process(uriParserResultView, content, requestContentType);
            if (createdEntity.getClass().equals(Child.class)) {
                response = postProcessCreateChild(createdEntity, uriParserResultView, contentType);
            } else {
                response = responseBuilder.build(uriParserResultView, createdEntity, contentType);
            }
        } finally {
            this.close();
        }
        return response;
    }


    @Override
    public ODataResponse updateEntity(final PutMergePatchUriInfo uriParserResultView, final InputStream content,
                                      final String requestContentType, final boolean merge, final String contentType) throws ODataException, ODataJPAModelException, ODataJPARuntimeException, ODataNotFoundException {
        logger.info("PUT: Entity {} called with key {}", uriParserResultView.getTargetEntitySet().getName(), uriParserResultView.getKeyPredicates().get(0).getLiteral());
        ODataResponse response = null;
        try {
            Object updatedEntity = jpaProcessor.process(uriParserResultView, content, requestContentType);
            response = responseBuilder.build(uriParserResultView, updatedEntity);
        } finally {
            this.close();
        }
        return response;
    }

    @Override
    public ODataResponse deleteEntity(DeleteUriInfo uriParserResultView, String contentType) throws ODataException {
        logger.info("DELETE: Entity {} called with key {}", uriParserResultView.getTargetEntitySet().getName(), uriParserResultView.getKeyPredicates().get(0).getLiteral());
        ODataResponse oDataResponse = null;
        try {
            this.oDataJPAContext.setODataContext(this.getContext());
            Object deletedEntity = this.jpaProcessor.process(uriParserResultView, contentType);
            oDataResponse = this.responseBuilder.build(uriParserResultView, deletedEntity);
        } finally {
            this.close();
        }
        return oDataResponse;
    }

    private ODataResponse postProcessCreateChild(Object createdEntity, PostUriInfo uriParserResultView, String contentType) throws ODataJPARuntimeException, ODataNotFoundException {
        Child child = (Child) createdEntity;
        if (child.getSurname() == null || child.getSurname().equalsIgnoreCase("")) {
            if (child.getMother().getSurname() != null && !child.getMother().getSurname().equalsIgnoreCase("")) {
                child.setSurname(child.getMother().getSurname());
            } else if (child.getMother().getSurname() != null && !child.getFather().getSurname().equalsIgnoreCase("")) {
                child.setSurname(child.getFather().getSurname());
            } else {
                child.setSurname("Gashi");
            }
        }
        return responseBuilder.build(uriParserResultView, createdEntity, contentType);
    }

}

package com.et.olingo.service;

import com.et.olingo.config.JerseyConfig;
import org.apache.olingo.odata2.api.ODataService;
import org.apache.olingo.odata2.api.ODataServiceFactory;
import org.apache.olingo.odata2.api.edm.provider.EdmProvider;
import org.apache.olingo.odata2.api.exception.ODataException;
import org.apache.olingo.odata2.api.processor.ODataContext;
import org.apache.olingo.odata2.api.processor.ODataSingleProcessor;
import org.apache.olingo.odata2.jpa.processor.api.ODataJPAContext;
import org.apache.olingo.odata2.jpa.processor.api.exception.ODataJPARuntimeException;
import org.apache.olingo.odata2.jpa.processor.api.factory.ODataJPAAccessFactory;
import org.apache.olingo.odata2.jpa.processor.api.factory.ODataJPAFactory;

import javax.persistence.EntityManager;
import javax.servlet.http.HttpServletRequest;

public class CustomODataServiceFactory extends ODataServiceFactory {

    private ODataJPAContext oDataJPAContext;
    private ODataContext oDataContext;

    @Override
    public final ODataService createService(final ODataContext context) throws ODataException {
        oDataContext = context;
        oDataJPAContext = initializeODataJPAContext();

        validatePreConditions();

        ODataJPAFactory factory = ODataJPAFactory.createFactory();
        ODataJPAAccessFactory accessFactory = factory.getODataJPAAccessFactory();

        if (oDataJPAContext.getODataContext() == null) {
            oDataJPAContext.setODataContext(context);
        }

        ODataSingleProcessor oDataSingleProcessor = new CustomODataJpaProcessor(
                oDataJPAContext
        );


        EdmProvider edmProvider = accessFactory.createJPAEdmProvider(oDataJPAContext);
        return createODataSingleProcessorService(edmProvider, oDataSingleProcessor);

    }

    private void validatePreConditions() throws ODataJPARuntimeException {
        if (oDataJPAContext.getEntityManager() == null) {
            throw ODataJPARuntimeException.throwException(ODataJPARuntimeException.ENTITY_MANAGER_NOT_INITIALIZED, null);
        }
    }

    public final ODataJPAContext getODataJPAContext()
            throws ODataJPARuntimeException {
        if (oDataJPAContext == null) {
            oDataJPAContext = ODataJPAFactory.createFactory()
                    .getODataJPAAccessFactory().createODataJPAContext();
        }
        if (oDataContext != null)
            oDataJPAContext.setODataContext(oDataContext);
        return oDataJPAContext;

    }

    protected ODataJPAContext initializeODataJPAContext() throws ODataJPARuntimeException {
        ODataJPAContext oDataJPAContext = this.getODataJPAContext();
        ODataContext oDataContext = oDataJPAContext.getODataContext();


        HttpServletRequest request = (HttpServletRequest) oDataContext.getParameter(
                ODataContext.HTTP_SERVLET_REQUEST_OBJECT);
        EntityManager entityManager = (EntityManager) request
                .getAttribute(JerseyConfig.EntityManagerFilter.EM_REQUEST_ATTRIBUTE);
        oDataJPAContext.setEntityManager(entityManager);


        oDataJPAContext.setPersistenceUnitName("default");
        oDataJPAContext.setContainerManaged(true);
        return oDataJPAContext;
    }
}

package com.et.olingo.service;

import org.springframework.stereotype.Component;

@Component
public class OdataJpaServiceFactory extends CustomODataServiceFactory {
    //need this wrapper class for the spring framework, otherwise we face issues when auto wiring directly the CustomODataServiceFactory
}

application.yaml

spring.h2.console.enabled=true
spring.h2.console.path=/console

以上只是一些关键代码，所有代码请参见下面代码仓库

代码仓库

• GitHub - Harries/springboot-demo: a simple springboot demo with some components for example: redis,solr,rockmq and so on.

3.测试

启动spring Boot应用

元数据查看

http://localhost:8080/odata/$metadata

插入

查询

4.引用

• https://github.com/ECasio/olingo-spring-example
• Apache Olingo Library
• Spring Boot集成olingo快速入门demo | Harries Blog™