查詢demo

Path path = Paths.get(util.Directory.GetAppPath("indexDir"));IndexReader reader = DirectoryReader.open(FSDirectory.open(path));//獲取IndexSearcher對象IndexSearcher indexSearcher = new IndexSearcher(reader);Query query = new TermQuery(new Term("title", "國"));//查詢數(shù)據(jù)TopDocs topDocs = indexSearcher.search(query, 10);ScoreDoc[] docs = topDocs.scoreDocs;for (ScoreDoc scoreDoc : docs) {Document res = indexSearcher.doc(scoreDoc.doc);System.out.println(res.get("title"));}

容易犯錯警告！！！

在構(gòu)造Term對象容易大意寫成如下

Query query = new Term("國");

則此時利用Term查詢不出來結(jié)果，因?yàn)榇藭r“國”被當(dāng)做成一個域，并沒有檢索內(nèi)容。

切記：利用lucene Term查詢一定要記得將域加上去,用來標(biāo)識搜索詞所在的字段名稱！！！

Query query = new TermQuery(new Term("title", "國"));

Term類說明文檔

介紹：Term術(shù)語表示文本中的單詞。這是搜索單位。它由兩個元素組成，一個字符串形式的單詞文本，另一個文本所在字段的名稱。請注意，術(shù)語可能表示的不僅僅是文本字段中的單詞，還包括日期、電子郵件地址、url等。

構(gòu)造方法：

Term(String?fld)	fld為域，傳入值為空
Term(String?fld,?BytesRef?bytes)	fld為域，值為字節(jié)流類型
Term(String?fld,?BytesRefBuilder?bytesBuilder)	fld為域，值為BytesRefBuilder類型
Term(String?fld,?String?text)	fld為域，值為String類型(最常用)

Term方法：

• field

  public final?String?field()

  Returns the field of this term. The field indicates the part of a document which this term came from.

• text

  public final?String?text()

  Returns the text of this term. In the case of words, this is simply the text of the word. In the case of dates and other types, this is an encoding of the object as a string.

• toString

  public static final?String?toString(BytesRef?termText)

  Returns human-readable form of the term text. If the term is not unicode, the raw bytes will be printed instead.

• bytes

  public final?BytesRef?bytes()

  Returns the bytes of this term, these should not be modified.

• equals

  public?boolean?equals(Object?obj)

  Overrides:

  equals?in class?Object

• hashCode

  public?int?hashCode()

  Overrides:

  hashCode?in class?Object

• compareTo

  public final?int?compareTo(Term?other)

  Compares two terms, returning a negative integer if this term belongs before the argument, zero if this term is equal to the argument, and a positive integer if this term belongs after the argument. The ordering of terms is first by field, then by text.

  Specified by:

  compareTo?in interface?Comparable<Term>

• toString

  public final?String?toString()

  Overrides:

  toString?in class?Object

• ramBytesUsed

  public?long?ramBytesUsed()

  Description copied from interface:?Accountable

  Return the memory usage of this object in bytes. Negative values are illegal.

說明文檔出處：http://lucene.apache.org/core/8_2_0/core/index.html

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