Java Spring中RestHighLevelClient存索引抛空指针但数据已写入ES

问题现象 #

使用RestHighLevelClient向Elasticsearch写入数据时，数据已成功写入（可通过/index/_search查询确认），但程序抛出以下异常：

2024-01-21 23:19:28.724 ERROR 14382 --- [nio-8080-exec-2] o.a.c.c.C.[.[.[/].[dispatcherServlet] : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.dao.DataAccessResourceFailureException: Unable to parse response body for Response{requestLine=PUT /product/_doc/98?timeout=1m HTTP/1.1, host=http://localhost:9200, response=HTTP/1.1 201 Created}; nested exception is java.lang.RuntimeException: Unable to parse response body for Response{requestLine=PUT /product/_doc/98?timeout=1m HTTP/1.1, host=http://localhost:9200, response=HTTP/1.1 201 Created}] with root cause

java.lang.NullPointerException: null
at java.base/java.util.Objects.requireNonNull(Objects.java:221) ~[na:na]
at org.elasticsearch.action.DocWriteResponse.(DocWriteResponse.java:116) ~[elasticsearch-7.15.2.jar:7.15.2]
at org.elasticsearch.action.index.IndexResponse.(IndexResponse.java:43) ~[elasticsearch-7.15.2.jar:7.15.2]

对应的RestHighLevelClient配置代码：

package com.springPractice.app.configuration;

import org.elasticsearch.client.RestHighLevelClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.elasticsearch.ElasticsearchProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.elasticsearch.client.ClientConfiguration;
import org.springframework.data.elasticsearch.client.RestClients;
import org.springframework.data.elasticsearch.config.AbstractElasticsearchConfiguration;
import org.springframework.http.HttpHeaders;

@Configuration
@ComponentScan(basePackages = {"com.springPractice.app"})
@EnableAutoConfiguration
public class ElasticsearchConfiguration extends AbstractElasticsearchConfiguration {

    private final ElasticsearchProperties elasticsearchProperties;

    @Autowired
    public ElasticsearchConfiguration(ElasticsearchProperties elasticsearchProperties) {
        this.elasticsearchProperties = elasticsearchProperties;
    }

    @Override
    @Bean
    public RestHighLevelClient elasticsearchClient() {
        final ClientConfiguration clientConfiguration = ClientConfiguration.builder()
                .connectedTo("localhost:9200")
                .withSocketTimeout(elasticsearchProperties.getSocketTimeout())
                .build();

        return RestClients.create(clientConfiguration).rest();
    }
}

问题原因 #

1. 版本不兼容：Spring Data Elasticsearch、RestHighLevelClient与Elasticsearch服务器版本不匹配，导致响应体解析时字段缺失，触发空指针。
2. 配置冲突：自定义配置类同时使用@EnableAutoConfiguration和继承AbstractElasticsearchConfiguration，导致Spring自动配置与自定义配置产生冲突，客户端初始化异常。
3. 依赖冲突：项目中存在多个版本的Elasticsearch相关依赖，导致类加载异常。

解决方案 #

1. 确保版本完全匹配 #

严格遵循Spring Data Elasticsearch与Elasticsearch的官方版本对应关系，例如：

• Spring Data Elasticsearch 4.3.x 对应 Elasticsearch 7.15.x
• 确保spring-boot-starter-data-elasticsearch、elasticsearch-rest-high-level-client的版本与ES服务器版本完全一致。

2. 简化客户端配置 #

去掉自定义配置类中的@EnableAutoConfiguration，避免自动配置冲突；或者直接使用Spring Boot自动配置，无需自定义配置类：
在application.properties中添加配置：

spring.elasticsearch.uris=http://localhost:9200
spring.elasticsearch.socket-timeout=30s

随后删除自定义的ElasticsearchConfiguration类，Spring会自动创建符合要求的RestHighLevelClient实例。

3. 清理依赖冲突 #

检查项目依赖文件（Maven的pom.xml或Gradle的build.gradle），确保只引入一套Elasticsearch相关依赖，排除重复或版本不一致的依赖。例如Maven中用<dependencyManagement>统一管理版本：

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.elasticsearch</groupId>
            <artifactId>elasticsearch</artifactId>
            <version>7.15.2</version>
        </dependency>
        <dependency>
            <groupId>org.elasticsearch.client</groupId>
            <artifactId>elasticsearch-rest-high-level-client</artifactId>
            <version>7.15.2</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-elasticsearch</artifactId>
            <version>4.3.5</version>
        </dependency>
    </dependencies>
</dependencyManagement>

4. 修正自定义配置（可选） #

如果必须保留自定义配置，移除@EnableAutoConfiguration并调整配置逻辑：

@Configuration
@ComponentScan(basePackages = {"com.springPractice.app"})
public class ElasticsearchConfiguration extends AbstractElasticsearchConfiguration {

    @Value("${spring.elasticsearch.uris}")
    private String esUris;

    @Value("${spring.elasticsearch.socket-timeout}")
    private Duration socketTimeout;

    @Override
    public RestHighLevelClient elasticsearchClient() {
        final ClientConfiguration clientConfiguration = ClientConfiguration.builder()
                .connectedTo(esUris.split(","))
                .withSocketTimeout(socketTimeout)
                .build();

        return RestClients.create(clientConfiguration).rest();
    }
}

内容的提问来源于stack exchange，提问作者Aravind