问题

这里使用Spring Data Neo4j来实现REST服务，不过这个是使用PagingAndSortingRepository来实现的。

Neo4j服务器

按照之前的neo4j的Hello World文章，准备一个neo4j服务器即可。

Spring Initializr

访问https://start.spring.io/网页，完成工程的初始化：
Spring Initializr初始化

Neo4j用户

src/main/resources/application.properties:

spring.neo4j.uri=bolt://localhost:7687
spring.neo4j.authentication.username=neo4j
spring.neo4j.authentication.password=neo4j

Entity

Person.java

package com.example.neo4j2.domain;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.neo4j.core.schema.GeneratedValue;
import org.springframework.data.neo4j.core.schema.Id;
import org.springframework.data.neo4j.core.schema.Node;

@Node
@Builder
@NoArgsConstructor
@AllArgsConstructor
@Data
public class Person {
    @Id
    @GeneratedValue
    private Long id;

    private String firstName;
    private String lastName;
}

注意这里需要使用lombok库了。需要添加如下依赖：

		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<optional>true</optional>
		</dependency>

具体使用可以参考《Gradle中lombok使用》。

Repository

添加pom.xml依赖库：

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-rest</artifactId>
    </dependency>

创建repository：

package com.example.neo4j2.repository;

import com.example.neo4j2.domain.Person;
import org.springframework.data.repository.PagingAndSortingRepository;
import org.springframework.data.repository.query.Param;
import org.springframework.data.rest.core.annotation.RepositoryRestResource;

import java.util.List;

@RepositoryRestResource(collectionResourceRel = "people", path = "people")
public interface PersonRepository extends PagingAndSortingRepository<Person, Long> {
    List<Person> findByLastName(@Param("name") String name);
}

Application

package com.example.neo4j2;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.neo4j.repository.config.EnableNeo4jRepositories;
import org.springframework.transaction.annotation.EnableTransactionManagement;

@EnableTransactionManagement
@EnableNeo4jRepositories
@SpringBootApplication
public class Neo4j2Application {

	public static void main(String[] args) {
		SpringApplication.run(Neo4j2Application.class, args);
	}

}

到这里，我们就构建好一个按照HAL方式的REST API了。

CRUD

查看整体：

curl http://localhost:8080
{
  "_links" : {
    "people" : {
      "href" : "http://localhost:8080/people{?page,size,sort}",
      "templated" : true
    },
    "profile" : {
      "href" : "http://localhost:8080/profile"
    }
  }
}%

查看所有people：

curl http://localhost:8080/people
{
  "_embedded" : {
    "people" : [ ]
  },
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people"
    },
    "profile" : {
      "href" : "http://localhost:8080/profile/people"
    },
    "search" : {
      "href" : "http://localhost:8080/people/search"
    }
  },
  "page" : {
    "size" : 20,
    "totalElements" : 0,
    "totalPages" : 0,
    "number" : 0
  }
}%

添加：

curl -i -X POST -H "Content-Type:application/json" -d '{  "firstName" : "Frodo",  "lastName" : "Baggins" }' http://localhost:8080/people
HTTP/1.1 201
Vary: Origin
Vary: Access-Control-Request-Method
Vary: Access-Control-Request-Headers
Location: http://localhost:8080/people/2
Content-Type: application/hal+json
Transfer-Encoding: chunked
Date: Thu, 24 Mar 2022 06:37:06 GMT

{
  "firstName" : "Frodo",
  "lastName" : "Baggins",
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people/2"
    },
    "person" : {
      "href" : "http://localhost:8080/people/2"
    }
  }
}%

查看：

curl http://localhost:8080/people
{
  "_embedded" : {
    "people" : [ {
      "firstName" : "Frodo",
      "lastName" : "Baggins",
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/people/2"
        },
        "person" : {
          "href" : "http://localhost:8080/people/2"
        }
      }
    } ]
  },
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people"
    },
    "profile" : {
      "href" : "http://localhost:8080/profile/people"
    },
    "search" : {
      "href" : "http://localhost:8080/people/search"
    }
  },
  "page" : {
    "size" : 20,
    "totalElements" : 1,
    "totalPages" : 1,
    "number" : 0
  }
}%

查询刚刚添加的一个：

curl http://localhost:8080/people/2
{
  "firstName" : "Frodo",
  "lastName" : "Baggins",
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people/2"
    },
    "person" : {
      "href" : "http://localhost:8080/people/2"
    }
  }
}%

查看搜索方法：

curl http://localhost:8080/people/search
{
  "_links" : {
    "findByLastName" : {
      "href" : "http://localhost:8080/people/search/findByLastName{?name}",
      "templated" : true
    },
    "self" : {
      "href" : "http://localhost:8080/people/search"
    }
  }
}%

使用搜索方法findByLastName:

curl http://localhost:8080/people/search/findByLastName\?name\=Baggins
{
  "_embedded" : {
    "people" : [ {
      "firstName" : "Frodo",
      "lastName" : "Baggins",
      "_links" : {
        "self" : {
          "href" : "http://localhost:8080/people/2"
        },
        "person" : {
          "href" : "http://localhost:8080/people/2"
        }
      }
    } ]
  },
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people/search/findByLastName?name=Baggins"
    }
  }
}%

替换：

curl -X PUT -H "Content-Type:application/json" -d '{ "firstName": "Bilbo", "lastName": "Baggins" }' http://localhost:8080/people/2
{
  "firstName" : "Bilbo",
  "lastName" : "Baggins",
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people/2"
    },
    "person" : {
      "href" : "http://localhost:8080/people/2"
    }
  }
}%

查看替换效果：

curl http://localhost:8080/people/2
{
  "firstName" : "Bilbo",
  "lastName" : "Baggins",
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people/2"
    },
    "person" : {
      "href" : "http://localhost:8080/people/2"
    }
  }
}%

修改：

curl -X PATCH -H "Content-Type:application/json" -d '{ "firstName": "Bilbo Jr." }' http://localhost:8080/people/2
{
  "firstName" : "Bilbo Jr.",
  "lastName" : "Baggins",
  "_links" : {
    "self" : {
      "href" : "http://localhost:8080/people/2"
    },
    "person" : {
      "href" : "http://localhost:8080/people/2"
    }
  }
}%

删除：

curl -X DELETE http://localhost:8080/people/2

总结

这里主要介绍Neo4j在Spring Rest方式，但总觉得HAL标准有点喧宾夺主的味道。HAL是使用REST的一种标准方式，但是这个标准还在起草中的路上。

参考：

Accessing Neo4j Data with REST
neo4j的Hello World
Gradle中lombok使用
Hypertext Application Language

Neo4j之HAL版REST（Spring）

问题