如何避免在Apache Solr 6中@Field注释的bean字段上设置ArrayList

Question

在非常简单的代码段中

SolrClient solrServer;
solrServer = new HttpSolrClient.Builder("http://localhost:8983/solr/test1")
        .build();
List<MyBean> myBeans = new LinkedList<>(Arrays.asList(new MyBean("a","1",1),new MyBean("b", "2", 2), new MyBean("c","3",3)));
String searchTerm = "a";
try {
    solrServer.addBeans(myBeans);
    solrServer.commit();
    SolrQuery solrQuery = new SolrQuery();
    solrQuery.set("q", searchTerm);
    QueryResponse queryResponse = solrServer.query(solrQuery);
    List<MyBean> foundDocuments = queryResponse.getBeans(MyBean.class);
    System.out.println(foundDocuments);
} catch (SolrServerException | IOException ex) {
    throw new RuntimeException(ex);
}

在Java SE主方法中使用新的Solr核心test1(在终端中使用bin/solr create_core -c test1创建(

public class MyBean {
    @Field
    private String property1;
    @Field
    private String property2;
    private int property3;
    public MyBean() {
    }
    public MyBean(String property1, String property2, int property3) {
        this.property1 = property1;
        this.property2 = property2;
        this.property3 = property3;
    }
    [public getter and setter for property1, property2 and property3]
}

我不断得到

Exception in thread "main" org.apache.solr.client.solrj.beans.BindingException: Could not instantiate object of class richtercloud.solr.bean.indexing.MyBean
    at org.apache.solr.client.solrj.beans.DocumentObjectBinder.getBean(DocumentObjectBinder.java:71)
    at org.apache.solr.client.solrj.beans.DocumentObjectBinder.getBeans(DocumentObjectBinder.java:50)
    at org.apache.solr.client.solrj.response.QueryResponse.getBeans(QueryResponse.java:618)
    at richtercloud.solr.bean.indexing.NewMain.main(NewMain.java:42)
Caused by: org.apache.solr.client.solrj.beans.BindingException: Exception while setting value : [a] on private java.lang.String richtercloud.solr.bean.indexing.MyBean.property1
    at org.apache.solr.client.solrj.beans.DocumentObjectBinder$DocField.set(DocumentObjectBinder.java:455)
    at org.apache.solr.client.solrj.beans.DocumentObjectBinder$DocField.inject(DocumentObjectBinder.java:438)
    at org.apache.solr.client.solrj.beans.DocumentObjectBinder.getBean(DocumentObjectBinder.java:67)
    ... 3 more
Caused by: java.lang.IllegalArgumentException: Can not set java.lang.String field richtercloud.solr.bean.indexing.MyBean.property1 to java.util.ArrayList
    at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
    at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
    at sun.reflect.UnsafeObjectFieldAccessorImpl.set(UnsafeObjectFieldAccessorImpl.java:81)
    at java.lang.reflect.Field.set(Field.java:764)
    at org.apache.solr.client.solrj.beans.DocumentObjectBinder$DocField.set(DocumentObjectBinder.java:449)
    ... 5 more

我无法理解为什么 Solr 想要在字符串字段上设置字符串列表。一个错误？

MCVE在 https://github.com/krichter722/solr-bean-indexing。我从 Solr 找到了检索对象，但它没有解释为什么我会收到异常，我觉得我正在做与那里建议的相同的事情。

我正在使用 Solr 6.5.1。

Answer 1

很可能

在您的核心http://localhost:8983/solr/test1字段中property1将multivalued属性设置为 true 。

这意味着字段property1必须是ArrayList。

如果您想要一个简单的String则应更改架构中的字段配置(multiValued="false"设置(。