正在用的Neo4j是当前最新版：3.1.0，各种踩坑。说一下如何在Neo4j 3.1.0中使用中文索引。选用了IKAnalyzer做分词器。
1. 首先参考文章：
https://segmentfault.com/a/1190000005665612
里面大致讲了用IKAnalyzer做索引的方式。但并不清晰，实际上，这篇文章的背景是用嵌入式Neo4j，即Neo4j一定要嵌入在你的Java应用中（https://neo4j.com/docs/java-reference/current/#tutorials-java-embedded），切记。否则无法使用自定义的Analyzer。其次，文中的方法现在用起来已经有问题了，因为Neo4j 3.1.0用了lucene5.5，故官方的IKAnalyzer已经不适用了。
2. 修正
转用 IKAnalyzer2012FF_u1.jar，在Google可以下载到（https://code.google.com/archive/p/ik-analyzer/downloads）。这个版本的IKAnalyzer是有小伙伴修复了IKAnalyzer不适配lucene3.5以上而修改的一个版本。但是用了这个包仍有问题，报错提示：
Caused by: java.lang.AbstractMethodError: org.apache.lucene.analysis.Analyzer.createComponents(Ljava/lang/String;)Lorg/apache/lucene/analysis/Analyzer$TokenStreamComponents;
即IKAnalyzer的Analyzer类和当前版本的lucene仍有不适配的地方。
解决方案：再增加两个类
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package com.uc.wa.function;
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import org.apache.lucene.analysis.Analyzer;
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import org.apache.lucene.analysis.Tokenizer;
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-
public
class IKAnalyzer5x extends Analyzer{
-
-
private
boolean useSmart;
-
-
public boolean useSmart() {
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return useSmart;
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}
-
-
public void setUseSmart(boolean useSmart) {
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this.useSmart = useSmart;
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}
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public IKAnalyzer5x(){
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this(
false);
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}
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-
public IKAnalyzer5x(boolean useSmart){
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super();
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this.useSmart = useSmart;
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}
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-
-
/**
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protected TokenStreamComponents createComponents(String fieldName, final Reader in) {
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Tokenizer _IKTokenizer = new IKTokenizer(in , this.useSmart());
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return new TokenStreamComponents(_IKTokenizer);
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}
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**/
-
-
-
/**
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* 重写最新版本的createComponents
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* 重载Analyzer接口，构造分词组件
-
*/
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@Override
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protected TokenStreamComponents createComponents(String fieldName) {
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Tokenizer _IKTokenizer =
new IKTokenizer5x(
this.useSmart());
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return
new TokenStreamComponents(_IKTokenizer);
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}
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}
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package com.uc.wa.function;
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-
import java.io.IOException;
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-
import org.apache.lucene.analysis.Tokenizer;
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import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
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import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
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import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
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import org.wltea.analyzer.core.IKSegmenter;
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import org.wltea.analyzer.core.Lexeme;
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-
public
class IKTokenizer5x extends Tokenizer{
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-
//IK�ִ���ʵ��
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private
IKSegmenter _IKImplement;
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-
//��Ԫ�ı�����
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private
final
CharTermAttribute termAtt;
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//��Ԫλ������
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private
final
OffsetAttribute offsetAtt;
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//��Ԫ�������ԣ������Է���ο�org.wltea.analyzer.core.Lexeme�еķ��ೣ����
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private
final
TypeAttribute typeAtt;
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//��¼���һ����Ԫ�Ľ���λ��
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private
int
endPosition;
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-
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/**
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public IKTokenizer(Reader in , boolean useSmart){
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super(in);
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offsetAtt = addAttribute(OffsetAttribute.class);
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termAtt = addAttribute(CharTermAttribute.class);
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typeAtt = addAttribute(TypeAttribute.class);
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_IKImplement = new IKSegmenter(input , useSmart);
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}**/
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/**
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* Lucene 5.x Tokenizer��������캯��
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* ʵ�����µ�Tokenizer�ӿ�
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* @param useSmart
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*/
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public IKTokenizer5x(boolean useSmart)
{
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super
();
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offsetAtt = addAttribute(OffsetAttribute.class);
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termAtt = addAttribute(CharTermAttribute.class);
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typeAtt = addAttribute(TypeAttribute.class);
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_IKImplement =
new
IKSegmenter(input , useSmart);
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}
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/* (non-Javadoc)
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* @see org.apache.lucene.analysis.TokenStream#incrementToken()
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*/
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@Override
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public boolean incrementToken() throws IOException
{
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//������еĴ�Ԫ����
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clearAttributes();
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Lexeme nextLexeme = _IKImplement.next();
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if
(nextLexeme !=
null
){
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//��Lexemeת��Attributes
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//���ô�Ԫ�ı�
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termAtt.append(nextLexeme.getLexemeText());
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//���ô�Ԫ����
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termAtt.setLength(nextLexeme.getLength());
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//���ô�Ԫλ��
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offsetAtt.setOffset(nextLexeme.getBeginPosition(), nextLexeme.getEndPosition());
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//��¼�ִʵ����λ��
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endPosition = nextLexeme.getEndPosition();
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//��¼��Ԫ����
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typeAtt.setType(nextLexeme.getLexemeTypeString());
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//����true��֪�����¸���Ԫ
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return
true
;
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}
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//����false��֪��Ԫ������
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return
false
;
-
}
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-
/*
-
* (non-Javadoc)
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* @see org.apache.lucene.analysis.Tokenizer#reset(java.io.Reader)
-
*/
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@Override
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public void reset() throws IOException
{
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super
.reset();
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_IKImplement.reset(input);
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}
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@Override
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public final void end()
{
-
// set final offset
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int
finalOffset = correctOffset(
this
.endPosition);
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offsetAtt.setOffset(finalOffset, finalOffset);
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}
-
}
解决 IKAnalyzer2012FF_u1.jar和lucene5不适配的问题。使用时用IKAnalyzer5x替换IKAnalyzer即可。
3. 最后
Neo4j中文索引建立和搜索示例：
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/**
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* 为单个结点创建索引
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*
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* @param propKeys
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*/
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public static void createFullTextIndex(long id, List<
String> propKeys) {
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log.info(
"method[createFullTextIndex] begin.propKeys<"+propKeys+
">");
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Index<Node> entityIndex =
null;
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try (Transaction tx = Neo4j.graphDb.beginTx()) {
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entityIndex = Neo4j.graphDb.index().forNodes(
"NodeFullTextIndex",
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MapUtil.stringMap(IndexManager.PROVIDER,
"lucene",
"analyzer", IKAnalyzer5x.
class.getName()));
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Node node = Neo4j.graphDb.getNodeById(id);
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log.info(
"method[createFullTextIndex] get node id<"+node.getId()+
"> name<"
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+node.getProperty(
"knowledge_name")+
">");
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/**获取node详细信息*/
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Set<Map.Entry<
String, Object>> properties = node.getProperties(propKeys.toArray(
new
String[
0]))
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.entrySet();
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for (Map.Entry<
String, Object>
property : properties) {
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log.info(
"method[createFullTextIndex] index prop<"+
property.getKey()+
":"+
property.getValue()+
">");
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entityIndex.add(node,
property.getKey(),
property.getValue());
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}
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tx.success();
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}
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}
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/**
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* 使用索引查询
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*
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* @param query
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* @return
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* @throws IOException
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*/
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public
static List<
Map<
String,
Object>> selectByFullTextIndex(
String[] fields,
String query) throws IOException {
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List<
Map<
String,
Object>> ret = Lists.newArrayList();
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try (Transaction tx = Neo4j.graphDb.beginTx()) {
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IndexManager index = Neo4j.graphDb.index();
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/**查询*/
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Index<Node> addressNodeFullTextIndex = index.forNodes(
"NodeFullTextIndex",
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MapUtil.stringMap(IndexManager.PROVIDER,
"lucene",
"analyzer", IKAnalyzer5x.class.getName()));
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Query q = IKQueryParser.parseMultiField(fields, query);
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IndexHits<Node> foundNodes = addressNodeFullTextIndex.query(q);
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for(Node n : foundNodes){
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Map<
String,
Object> m = n.getAllProperties();
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if(!Float.isNaN(foundNodes.currentScore())){
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m.put(
"score", foundNodes.currentScore());
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}
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log.info(
"method[selectByIndex] score<"+foundNodes.currentScore()+
">");
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ret.add(m);
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}
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tx.success();
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}
catch (IOException e) {
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log.error(
"method[selectByIndex] fields<"+Joiner.on(
",").join(fields)+
"> query<"+query+
">", e);
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throw e;
-
}
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return ret;
-
}
注意到，在这里我用了IKQueryParser，即根据我们的查询词和要查询的字段，自动构造Query。这里是绕过了一个坑：用lucene查询语句直接查的话，是有问题的。比如：“address:南昌市” 查询语句，会搜到所有带市字的地址，这是非常不合理的。改用IKQueryParser即修正这个问题。IKQueryParser是IKAnalyzer自带的一个工具，但在 IKAnalyzer2012FF_u1.jar却被删减掉了。因此我这里重新引入了原版IKAnalyzer的jar包，项目最终是两个jar包共存的。
到这里坑就踩得差不多了。
原文地址：https://blog.csdn.net/hereiskxm/article/details/54345261 </div>
