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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。

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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

<?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)returnid(u) as id,u.name as name,u.age as age,u.sex as sex</select><select id="getById" resultMap="userMap">match(u:user)whereid(u) = #{id}returnid(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 {@Overridepublic boolean supportsLimit() {return true;}@Overridepublic 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();}@Overridepublic 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*/@Overridepublic 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*/@Overridepublic 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*/@Overridepublic JSONObject getNullableResult(ResultSet rs, int columnIndex) throws SQLException {String sqlJson = rs.getString(columnIndex);if (null != sqlJson){return JSONObject.parseObject(sqlJson);}return null;}@Overridepublic 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 {@Resourceprivate MybatisSqlSession mybatisSqlSession;@Resourceprivate 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 nmybatisSqlSession.insert("neo4jExampleMapper.add", model);}@Transactional(rollbackFor = Exception.class)public void addAndUpdate( ExampleUserModel model) {//MATCH (n:user) return nSystem.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);}

总结

以上只是摘取了框架中的一部分代码，本文只是提供了一些具体设计思路，其它部分需要自行完善。