mybatis 集成neo4j实现

news2024/11/13 9:38:23

文章目录

前言
一、引入jar包依赖
二、配置 application.properties
三、Mybatis Neo4j分页插件
四、Mybatis Neo4j自定义转换器handler
五、Mybatis+Neo4j代码示例
总结

前言

MyBatis是一个基于Java语言的持久层框架，它通过XML描述符或注解将对象与存储过程或SQL语句进行映射，并提供了普通SQL查询、存储过程和高级映射等操作方式，使得操作数据库变得非常方便。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。
Neo4j 是一个高性能的NOSQL 图数据库，它将结构化数据存储在图中而不是表中。它非常适合于表示和查询高度连接的数据，例如社交网络、推荐系统和知识图谱等。
Neo4j数据模型和查询语言 Cypher 与传统的关系型数据库有很大的不同。因此原生MyBatis 并不支持 Neo4j，需要引入第三方jar包，并通过配置和编码的方式进行集成。

一、引入jar包依赖

POM.XML 添加依赖neo4j-jdbc-driver  mybatis-spring-boot-starter

         <dependency>
            <groupId>org.neo4j</groupId>
            <artifactId>neo4j-jdbc-driver</artifactId>
            <version>4.0.0</version>
        </dependency>
		<dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>

二、配置 application.properties

######## neo4j图数据源
spring.datasource.neo4j.username=neo4j
spring.datasource.neo4j.password=xxxxx
spring.datasource.neo4j.url=jdbc:neo4j:http://192.168.3.179:7474
spring.datasource.neo4j.driver-class-name=org.neo4j.jdbc.http.HttpDriver
#spring.datasource.neo4j.url=jdbc:neo4j:bolt://localhost:7687
#spring.datasource.neo4j.driver-class-name=org.neo4j.jdbc.bolt.BoltDriver
spring.datasource.neo4j.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.target-names=neo4j

创建mapper文件
在这里插入图片描述

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="neo4jExampleMapper" >
    <!-- 自定义结果集-->
    <resultMap id="userMap" type="example.neo4j.ExampleUserModel">
        <id property="id" column="id"/>
        <result property="name" column="name"/>
        <result property="age" column="age"/>
        <result property="sex" column="sex"/>
    </resultMap>
    <select id="getAll" resultMap="userMap">
		match
          (u:user)
		return
		  id(u) as id,u.name as name,u.age as age,u.sex as sex
	</select>

    <select id="getById" resultMap="userMap">
		match
		  (u:user)
		where
		  id(u) = #{id}
		return
          id(u) as id,u.name as name,u.age as age,u.sex as sex
	</select>
	
	<insert id="add" parameterType="example.neo4j.ExampleUserModel">
        create(u:user{name:#{name},age:#{age},sex:#{sex}})
    </insert>

    <update id="update">
        match (u:user)
        where id(u) = #{id}
        set u.name = #{name},u.age = #{age},u.sex = #{sex}
    </update>
</mapper>

三、Mybatis Neo4j分页插件

public class Neo4jDialect extends PageDialect {

    @Override
    public boolean supportsLimit() {
        return true;
    }

    @Override
    public String getLimitString(String sql, int offset, int limit) {
        return getLimitString(sql, offset, Integer.toString(offset), Integer.toString(limit));
    }

    private String getLimitString(final String sql,
                                  final int offset,
                                  final String offsetPlaceholder,
                                  final String limitPlaceholder) {
        StringBuilder stringBuilder = new StringBuilder(getLineSql(sql));
        if (offset > 0) {
            stringBuilder.append(" skip ").append(offsetPlaceholder).append(" limit ").append(limitPlaceholder);
        } else {
            stringBuilder.append(" limit ").append(limitPlaceholder);
        }

        return stringBuilder.toString();
    }
    @Override
    public String getCountString(String sql) {
        String newsql;
        if (CountHelper.containOrder(sql) && !CountHelper.containOver(sql)) {
            newsql = getNonOrderByPart(sql);
        } else {
            newsql = sql;
        }

        return "call { " + newsql.trim() + "} return count(*) as tmp_count";
    }
    protected String getLineSql(String sql) {
        return sql.replaceAll("[\r\n]", " ").replaceAll("\\s{2,}", " ");
    }
    private static String getNonOrderByPart(String sql) {
        return CountHelper.removeOrders(sql);
    }
}

四、Mybatis Neo4j自定义转换器handler


/**
 * 将查询结果中的json格式的字段进行转换的自定义转换器，转换为实体类的JSONObject属性
 */
@MappedTypes(JSONObject.class)
@MappedJdbcTypes(JdbcType.VARCHAR)
public class JSONObjectTypeHandler extends BaseTypeHandler<JSONObject> {

   /**
    * 设置非空参数
    * @param ps
    * @param i
    * @param parameter
    * @param jdbcType
    * @throws SQLException
    */
   @Override
   public void setNonNullParameter(PreparedStatement ps, int i, JSONObject parameter, JdbcType jdbcType) throws SQLException {
       ps.setString(i, String.valueOf(parameter.toJSONString()));
   }

   /**
    * 根据列名，获取可以为空的结果
    * @param rs
    * @param columnName
    * @return
    * @throws SQLException
    */
   @Override
   public JSONObject getNullableResult(ResultSet rs, String columnName) throws SQLException {
       String sqlJson = rs.getString(columnName);
       if (null != sqlJson){
           return JSONObject.parseObject(sqlJson);
       }
       return null;
   }

   /**
    * 根据列索引，获取可以为空的结果
    * @param rs
    * @param columnIndex
    * @return
    * @throws SQLException
    */
   @Override
   public JSONObject getNullableResult(ResultSet rs, int columnIndex) throws SQLException {
       String sqlJson = rs.getString(columnIndex);
       if (null != sqlJson){
           return JSONObject.parseObject(sqlJson);
       }
       return null;
   }

   @Override
   public JSONObject getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {
       String sqlJson = cs.getString(columnIndex);
       if (null != sqlJson){
           return JSONObject.parseObject(sqlJson);
       }
       return null;
   }
}

五、Mybatis+Neo4j代码示例

对Neo4j的增改查

public class Neo4jExampleService {
	@Resource
    private MybatisSqlSession mybatisSqlSession;
	@Resource
	private DataSource datasource;
	
	
	public  ExampleUserModel  getUserInfo(String userid) {
		ExampleUserModel user=mybatisSqlSession.selectById("neo4jExampleMapper.getById", userid);
		return user;
	}
	public  List<ExampleUserModel>  getAllUser() {
		List<ExampleUserModel> userList=mybatisSqlSession.selectByParams("neo4jExampleMapper.getAll", null);
		return userList;
	}
	@SuppressWarnings("unchecked")
	public  DataPaging  getPageUser(Integer page) {
		PageRequest pageRequest = new PageRequest(page, 4, null);
		DataPaging pageing=mybatisSqlSession.selectPaging("neo4jExampleMapper.getAll", pageRequest);
		return pageing;
	}
    public void insert( ExampleUserModel model) {
    	//MATCH (n:user) return n
        mybatisSqlSession.insert("neo4jExampleMapper.add", model);
    }
    @Transactional(rollbackFor = Exception.class)
    public void addAndUpdate( ExampleUserModel model) {
    	//MATCH (n:user) return n
    	System.out.println("before insert "+datasource);
        mybatisSqlSession.insert("neo4jExampleMapper.add", model);
        System.out.println("after insert");
        ExampleUserModel updateUser=new ExampleUserModel();
        updateUser.setId(1237L);
        updateUser.setName("dTest");
        updateUser.setAge(20);
        mybatisSqlSession.update("neo4jExampleMapper.update", updateUser);
    }