Lucene的查询语句

2.RangeQuery用于区间查询,RangeQuery的第三个参数表示是开区间还是闭区间。

QueryParser会构建从begin到end之间的N个查询进行查询。

 Term begin, end;
 Searcher searcher = new IndexSearcher(dbpath);
 begin = new Term("pubmonth","199801");
 end = new Term("pubmonth","199810");
 RangeQuery query = new RangeQuery(begin, end, true);

RangeQuery本质是比较大小。所以如下查询也是可以的，但是意义就于上面不大一样了，总之是大小的比较
设定了一个区间，在区间内的都能够搜索出来，这里就存在一个比较大小的原则，比如字符串会首先比较第一个字符，这样与字符长度没有关系。
begin = new Term("pubmonth","19");
 end = new Term("pubmonth","20");
 RangeQuery query = new RangeQuery(begin, end, true);


3.PrefixQuery.对于TermQuery，必须完全匹配（用Field.Keyword生成的字段）才能够查询出来。
这就制约了查询的灵活性，PrefixQuery只需要匹配value的前面任何字段即可。如Field为name，记录
中那么有jackliu,jackwu,jackli,那么使用jack就可以查询出所有的记录。QueryParser creates a PrefixQuery
for a term when it ends with an asterisk (*) in query expressions.

 IndexSearcher searcher = new IndexSearcher(directory);
 Term term = new Term("category", "/technology/computers/programming");
 PrefixQuery query = new PrefixQuery(term);
 Hits hits = searcher.search(query);

4.BooleanQuery.上面所有的查询都是基于单个field的查询，多个field怎么查询呢，BooleanQuery
就是解决多个查询的问题。通过add(Query query, boolean required, boolean prohibited)加入
多个查询.通过BooleanQuery的嵌套可以组合非常复杂的查询。
 
 IndexSearcher searcher = new IndexSearcher(directory);
 TermQuery searchingBooks =
 new TermQuery(new Term("subject","search"));

 RangeQuery currentBooks =
 new RangeQuery(new Term("pubmonth","200401"),
  new Term("pubmonth","200412"),true);
  
 BooleanQuery currentSearchingBooks = new BooleanQuery();
 currentSearchingBooks.add(searchingBook s, true, false);
 currentSearchingBooks.add(currentBooks, true, false);
 Hits hits = searcher.search(currentSearchingBooks);

BooleanQuery的add方法有两个boolean参数：
true＆false：表明当前加入的子句是必须要满足的；
false＆true：表明当前加入的子句是不可以被满足的；
false＆false：表明当前加入的子句是可选的；
true＆true：错误的情况。

QueryParser handily constructs BooleanQuerys when multiple terms are specified.
Grouping is done with parentheses, and the prohibited and required flags are
set when the –, +, AND, OR, and NOT operators are specified.

5.PhraseQuery进行更为精确的查找。它能够对索引文本中的两个或更多的关键词的位置进行
限定。如搜查包含A和B并且A、B之间还有一个文字。Terms surrounded by double quotes in 
QueryParser parsed expressions are translated into a PhraseQuery.
The slop factor defaults to zero, but you can adjust the slop factor 
by adding a tilde (~) followed by an integer. 
For example, the expression "quick fox"~3

http://www.blogjava.net/persister/archive/2009/07/14/286634.html

比如下面的情况：

    doc.add(Field.Text("field", "the quick brown fox jumped over the lazy dog"));
那么：
    String[] phrase = new String[] {"quick", "fox"};
    assertFalse("exact phrase not found", matched(phrase, 0));
    assertTrue("close enough", matched(phrase, 1));
multi-terms:
    assertFalse("not close enough", matched(new String[] {"quick", "jumped", "lazy"}, 3));
    assertTrue("just enough", matched(new String[] {"quick", "jumped", "lazy"}, 4));
    assertFalse("almost but not quite", matched(new String[] {"lazy", "jumped", "quick"}, 7));
    assertTrue("bingo", matched(new String[] {"lazy", "jumped", "quick"}, 8));

数字表示slop，通过如下方式设置，表示按照顺序从第一个字段到第二个字段之间间隔的term个数。
    query.setSlop(slop);

顺序很重要：
   

  String[] phrase = new String[] {"fox", "quick"};
  assertFalse("hop flop", matched(phrase, 2));
  assertTrue("hop hop slop", matched(phrase, 3));

6.WildcardQuery.WildcardQuery比PrefixQuery提供了更细的控制和更大的灵活性，这个最容易
理解和使用。

7.FuzzyQuery.这个Query比较特别，它会查询与关键字长得很像的其他记录。QueryParser 
supports FuzzyQuery by suffixing a term with a tilde (~),for exmaple wuzza~.

public void testFuzzy() throws Exception {
  indexSingleFieldDocs(new Field[] {
  Field.Text("contents", "fuzzy"),
  Field.Text("contents", "wuzzy")
  });
  IndexSearcher searcher = new IndexSearcher(directory);
  Query query = new FuzzyQuery(new Term("contents", "wuzza"));
  Hits hits = searcher.search(query);
  assertEquals("both close enough", 2, hits.length());
  assertTrue("wuzzy closer than fuzzy",
  hits.score(0) != hits.score(1));
  assertEquals("wuzza bear","wuzzy", hits.doc(0).get("contents"));
 }

Lucene的Query

8.PhrasePrefixQuery 主要用来进行同义词查询的：
    IndexWriter writer = new IndexWriter(directory, new WhitespaceAnalyzer(), true);
    Document doc1 = new Document();
    doc1.add(Field.Text("field", "the quick brown fox jumped over the lazy dog"));
    writer.addDocument(doc1);
    Document doc2 = new Document();
    doc2.add(Field.Text("field","the fast fox hopped over the hound"));
    writer.addDocument(doc2);

    PhrasePrefixQuery query = new PhrasePrefixQuery();
    query.add(new Term[] {new Term("field", "quick"), new Term("field", "fast")});
    query.add(new Term("field", "fox"));

    Hits hits = searcher.search(query);
    assertEquals("fast fox match", 1, hits.length());
    query.setSlop(1);
    hits = searcher.search(query);
    assertEquals("both match", 2, hits.length());

转自：http://www.blogjava.net/persister/archive/2009/06/08/280567.html
Lucene基本的查询语句：
 Searcher searcher = new IndexSearcher(dbpath);
 Query query = QueryParser.parse(searchkey, searchfield,
     new StandardAnalyzer());
 Hits hits = searcher.search(query);
下面是Query的各种子查询，他们QueryParser都有对应关系。
1.TermQuery常用，对一个Term（最小的索引块，包含一个field名字和值）进行索引查询。

Term直接与QueryParser.parse里面的key和field直接对应。

 IndexSearcher searcher = new IndexSearcher(directory);
 Term t = new Term("isbn", "1930110995");
 Query query = new TermQuery(t);
 Hits hits = searcher.search(query);