一、目前存在的問題

在getSameWords()方法中,我們使用map臨時存放了兩個鍵值對用來測試,實際開發中,往往需要很多的這種鍵值對來處理,比如從某個同義詞詞典裡面獲取值之類的,所以說,我們需要一個類,根據key提供近義詞。

為了能更好的適應應用場景,我們先定義一個介面,其中定義一個getSameWords()方法,在定義一個實現類,實現getSameWords()方法,當我們需要更換字典的時候,更換實現類,重新實現getSameWords()方法提供不同的同義詞即可。

二、程式碼實現

package com.wsy;

public interface SameWordContext {
    public String[] getSameWords(String key);
}
package com.wsy;

import java.util.HashMap;
import java.util.Map;

public class SimpleSameWordContext implements SameWordContext {
    Map<String, String[]> map = new HashMap();

    public SimpleSameWordContext() {
        map.put("中國", new String[]{"天朝", "大陸"});
        map.put("我", new String[]{"俺", "咱"});
        // 或者是讀取同義詞詞典,將字典裡的值放入map中
    }

    @Override
    public String[] getSameWords(String key) {
        return map.get(key);
    }
}
package com.wsy;

import org.apache.lucene.analysis.TokenFilter;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;

public class MySameTokenFilter extends TokenFilter {
    private CharTermAttribute charTermAttribute;
    private PositionIncrementAttribute positionIncrementAttribute;
    private State state;
    private Stack<String> stack;
    private SameWordContext sameWordContext;

    protected MySameTokenFilter(TokenStream input, SameWordContext sameWordContext) {
        super(input);
        charTermAttribute = this.addAttribute(CharTermAttribute.class);
        positionIncrementAttribute = this.addAttribute(PositionIncrementAttribute.class);
        stack = new Stack();
        this.sameWordContext = sameWordContext;
    }

    // 這裡的incrementToken()方法有點像iterator.hasnext()
    // 如果後面還有待處理的元素,那麼返回true
    // 如果後面沒有待處理的元素,那麼返回false
    @Override
    public boolean incrementToken() throws IOException {
        // 如果棧中有同義詞
        if (stack.size() > 0) {
            // 出棧並拿到這個元素
            String string = stack.pop();
            // 還原狀態即獲取到之前狀態的一個副本
            restoreState(state);
            // 將當前token的內容清空並新增上同義詞
            charTermAttribute.setEmpty();
            charTermAttribute.append(string);
            // 設定當前token和前一個token的間隔是0,也就是和前一個的位置一樣
            positionIncrementAttribute.setPositionIncrement(0);
            return true;
        }
        if (input.incrementToken() == false) {
            return false;
        }
        if (getSameWords(charTermAttribute.toString())) {
            // 如果有同義詞就捕獲當前狀態
            state = captureState();
        }
        return true;
    }

    private boolean getSameWords(String key) {
        String[] sameWords = sameWordContext.getSameWords(key);
        if (sameWords != null) {
            for (String sameWord : sameWords) {
                stack.push(sameWord);
            }
            return true;
        }
        return false;
    }
}
package com.wsy;

import com.chenlb.mmseg4j.Dictionary;
import com.chenlb.mmseg4j.MaxWordSeg;
import com.chenlb.mmseg4j.analysis.MMSegTokenizer;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;

import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;

public class MySameAnalyzer extends Analyzer {
    private SameWordContext sameWordContext;

    public MySameAnalyzer(SameWordContext sameWordContext) {
        this.sameWordContext = sameWordContext;
    }

    @Override
    public TokenStream tokenStream(String string, Reader reader) {
        // 指定分詞字典
        Dictionary dictionary = Dictionary.getInstance("E:\\Lucene\\mmseg4j-1.8.5\\data");
        return new MySameTokenFilter(new MMSegTokenizer(new MaxWordSeg(dictionary), reader), sameWordContext);
    }

    public static void displayAllToken(String string, Analyzer analyzer) {
        try {
            TokenStream tokenStream = analyzer.tokenStream("content", new StringReader(string));
            // 放入屬性資訊,為了檢視流中的資訊
            // 位置增量資訊,語彙單元之間的距離
            PositionIncrementAttribute positionIncrementAttribute = tokenStream.addAttribute(PositionIncrementAttribute.class);
            // 每個語彙單元的位置偏移量資訊
            OffsetAttribute offsetAttribute = tokenStream.addAttribute(OffsetAttribute.class);
            // 每一個語彙單元的分詞資訊
            CharTermAttribute charTermAttribute = tokenStream.addAttribute(CharTermAttribute.class);
            // 使用的分詞器的型別資訊
            TypeAttribute typeAttribute = tokenStream.addAttribute(TypeAttribute.class);
            while (tokenStream.incrementToken()) {
                System.out.println(positionIncrementAttribute.getPositionIncrement() + ":" + charTermAttribute + "[" + offsetAttribute.startOffset() + "-" + offsetAttribute.endOffset() + "]-->" + typeAttribute.type());
            }
            System.out.println("----------------------------");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {
        String string = "我來自中國";
        MySameAnalyzer analyzer = new MySameAnalyzer(new SimpleSameWordContext());
        Directory directory = new RAMDirectory();
        IndexWriter indexWriter = new IndexWriter(directory, new IndexWriterConfig(Version.LUCENE_35, analyzer));
        Document document = new Document();
        document.add(new Field("content", string, Field.Store.YES, Field.Index.ANALYZED));
        indexWriter.addDocument(document);
        indexWriter.close();
        IndexSearcher indexSearcher = new IndexSearcher(IndexReader.open(directory));
        TopDocs topDocs = indexSearcher.search(new TermQuery(new Term("content", "天朝")), 10);
        ScoreDoc[] scoreDocs = topDocs.scoreDocs;
        if (scoreDocs.length > 0) {
            document = indexSearcher.doc(scoreDocs[0].doc);
            System.out.println(document.get("content"));
        }
        MySameAnalyzer.displayAllToken(string, analyzer);
    }
}