引入SolrJ依赖后生产环境Solr连接失败及健康检查报错排查

我通过SolrJ连接Solr，POM依赖配置如下：

<dependency>
    <groupId>org.apache.solr</groupId>
    <artifactId>solr-solrj</artifactId>
</dependency>

本地环境连接localhost时正常，业务代码如下：

public class SolrJSearcher {

    public String solrSearch() throws SolrServerException, IOException {
        String collection = "Users";
        SolrClient client = new HttpSolrClient.Builder("http://localhost:8983/solr/" + collection).build();
        SolrQuery query = new SolrQuery();
        query.setQuery("*:*");
        query.setRows(1);
        QueryResponse response = client.query(query);
        SolrDocumentList results = response.getResults();
        String returnValue = JSONUtil.toJSON(results);
        return returnValue;
    }
}

但将主机名改为生产环境地址后无法连接，更奇怪的是，即使删除上述业务方法只保留POM依赖，部署时仍出现如下报错：

2022-11-21 17:09:31.013+0100 WARN [org.springframework.boot.actuate.solr.SolrHealthIndicator] (http-nio-8080-exec-1) [anonymousUser/NONE/d145ccb7-4dfe-4acd-8b6a-b924900d621d] Solr health check failed
org.apache.solr.client.solrj.SolrServerException: Server refused connection at: http://127.0.0.1:8983/solr 
    at org.apache.solr.client.solrj.impl.HttpSolrClient.executeMethod(HttpSolrClient.java:672)
    at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:265)
    at org.apache.solr.client.solrj.impl.HttpSolrClient.request(HttpSolrClient.java:248)
    at org.apache.solr.client.solrj.SolrRequest.process(SolrRequest.java:211)
    at org.apache.solr.client.solrj.SolrRequest.process(SolrRequest.java:228)
    at org.springframework.boot.actuate.solr.SolrHealthIndicator$RootStatusCheck.getStatus(SolrHealthIndicator.java:115)
    at org.springframework.boot.actuate.solr.SolrHealthIndicator.initializeStatusCheck(SolrHealthIndicator.java:78)
    at org.springframework.boot.actuate.solr.SolrHealthIndicator.initializeStatusCheck(SolrHealthIndicator.java:66)
    at org.springframework.boot.actuate.solr.SolrHealthIndicator.doHealthCheck(SolrHealthIndicator.java:53)
    at org.springframework.boot.actuate.health.AbstractHealthIndicator.health(AbstractHealthIndicator.java:82)
    at org.springframework.boot.actuate.health.HealthIndicator.getHealth(HealthIndicator.java:37)
    at org.springframework.boot.actuate.health.HealthEndpointWebExtension.getHealth(HealthEndpointWebExtension.java:85)
    at org.springframework.boot.actuate.health.HealthEndpointWebExtension.getHealth(HealthEndpointWebExtension.java:44)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getContribution(HealthEndpointSupport.java:99)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getAggregateHealth(HealthEndpointSupport.java:110)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getContribution(HealthEndpointSupport.java:96)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getHealth(HealthEndpointSupport.java:74)
    at org.springframework.boot.actuate.health.HealthEndpointSupport.getHealth(HealthEndpointSupport.java:61)
    at org.springframework.boot.actuate.health.HealthEndpointWebExtension.health(HealthEndpointWebExtension.java:71)
    at org.springframework.boot.actuate.health.HealthEndpointWebExtension.health(HealthEndpointWebExtension.java:60)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:282)
    at org.springframework.boot.actuate.endpoint.invoke.reflect.ReflectiveOperationInvoker.invoke(ReflectiveOperationInvoker.java:77)
    at org.springframework.boot.actuate.endpoint.annotation.AbstractDiscoveredOperation.invoke(AbstractDiscoveredOperation.java:60)
    at

请问该问题的原因是什么？是否需要配置以阻止自动连接localhost？

原因分析 #

报错信息里的SolrHealthIndicator是Spring Boot Actuator的健康检查组件。当项目引入solr-solrj依赖且启用了Actuator（默认引入Actuator starter即启用），Spring Boot会自动配置该组件，它默认尝试连接http://127.0.0.1:8983/solr做健康检查——这个逻辑和你自己业务代码里的SolrClient实例无关，所以即使删除业务代码，依然会触发报错。

解决方案 #

有两种处理方式：

1. 配置正确的Solr地址供健康检查使用

在配置文件（如application.properties或application.yml）中指定生产环境的Solr地址，覆盖默认值：

# application.properties
spring.data.solr.host=http://你的生产环境Solr地址:端口/solr

YAML格式：

# application.yml
spring:
  data:
    solr:
      host: http://你的生产环境Solr地址:端口/solr

配置后，Actuator的健康检查会使用这个地址，同时你也可以在业务代码里读取该配置，避免硬编码：

@Value("${spring.data.solr.host}")
private String solrHost;

public String solrSearch() throws SolrServerException, IOException {
    String collection = "Users";
    SolrClient client = new HttpSolrClient.Builder(solrHost + "/" + collection).build();
    // 后续业务逻辑不变
}

2. 禁用Solr健康检查

如果项目不需要Solr的健康检查，可以直接关闭该功能：

# application.properties
management.health.solr.enabled=false

YAML格式：

# application.yml
management:
  health:
    solr:
      enabled: false

内容的提问来源于stack exchange，提问作者QueryQuasar