CustomScoreQuery类

 

构造函数

 

Constructor Summary

( subQuery) 

          Create a CustomScoreQuery over input subQuery.

( subQuery, ... scoringQueries) 

          Create a CustomScoreQuery over input subQuery and a .

( subQuery,  scoringQuery) 

          Create a CustomScoreQuery over input subQuery and a .

 

FunctionQuery，FunctionQuery(ValueSource valueSource)，自定义评分query;

ValueSource，读取某个域的评分，ValueSource valueSource = new IntFieldSource("score");读取Score域的评分;

 

通过重写getCustomScoreProvider(AtomicReaderContext)修改评分计算方法

getCustomScoreProvider默认计算方法

super.getCustomScoreProvider(reader):原有评分*传入评分域评分

 

CustomScoreProvider类

 

重写 customScore(

int doc, 

float subQueryScore, 

float valSrcScore)方法，

1. doc是文件编号
2. subQueryScore是原有评分值
3. valSrcScore是传入域的评分值

在这个方法里，可以编写自己的算法，操作两个评分值

 

 

1、原有评分*传入的评分域打分

 

 

1 Query subquery = new TermQuery(new Term("content", "java")); 2  //评分域 3 ValueSource valueSource = new IntFieldSource("score"); 4 FunctionQuery fq = new FunctionQuery(valueSource );//自定义评分query 5 //自定义评分query 6 MyCustomScoreQuery myCustomScoreQuery = new MyCustomScoreQuery(subquery ,fq ); 7  8 private class MyCustomScoreQuery extends CustomScoreQuery { 9 10               public MyCustomScoreQuery(Query subQuery , FunctionQuery fq) {11                      super(subQuery ,fq ); 12 // TODO Auto-generated constructor stub 13  } 14 15 protected CustomScoreProvider getCustomScoreProvider(AtomicReaderContext reader ) throws IOException { 16 return super .getCustomScoreProvider(reader); 17  } 18 }

 

2、原有评分/传入评分域打分

 

1 private class MyCustomScoreQuery extends CustomScoreQuery { 2   3      public MyCustomScoreQuery(Query subQuery , FunctionQuery fq) { 4                      super(subQuery ,fq ); 5                      // TODO Auto-generated constructor stub 6              } 7               8               protected CustomScoreProvider getCustomScoreProvider(AtomicReaderContext reader ) throws IOException { 9                      //return super.getCustomScoreProvider(reader);10                      return new MyCustomScoreProvider(reader); 11  } 12  } 13 14 private class MyCustomScoreProvider extends CustomScoreProvider { 15 public MyCustomScoreProvider(AtomicReaderContext reader){ 16 super(reader ); 17  } 18 19 public float customScore(int doc, float subQueryScore, float valSrcScore) throws IOException{ 20 //return super.customScore(doc, subQueryScore, valSrcScore); 21 return subQueryScore /valSrcScore; 22  } 23 }

 

 

3、根据文件名评分，指定的特殊文件名获得更高的评分比重

 

[1]从reader的缓存中获得文件名

Lucene4.0前，Sring[] filenames = FieldCache. DEFAULT.getString(  "filename" );

Lucene4.0后，没有了getString，getByte也变成了 Deprecate。

 

所以采用了下面的方法获取StringField

Binaryvalues filenames = FieldCache.

DEFAULT.getTerms( atomicReader, "filename" , 

false);

 

[2]针对每个文件名进行操作

String filename = filenames.get(doc ).utf8ToString();