lucene建立索引时候的用到的一些文档和目录操作

在前边的文章中多是用的添加一个document，这里介绍一下其它的文档操作
1,按照编号删除

 
  public void deleteDoc(String indexDir) throws Exception {
    IndexReader reader = IndexReader.open(indexDir);
    reader.delete(1);
    reader.close();
  }

2,根据term来删除

 
  public void deleteDocWithTerm(String indexDir) throws Exception {
    IndexReader reader = IndexReader.open(indexDir);
    reader.delete(new Term("city", "beijing"));
    reader.close();
  }

3,取消删除

 
  public void undeleteDoc(String indexDir) throws Exception {
    IndexReader reader = IndexReader.open(indexDir);
    reader.delete(1);
    reader.undeleteAll();
    reader.close();
  }

4,删除后优化

 
  public void mergeDoc(String indexDir) throws Exception {
    IndexReader reader = IndexReader.open(indexDir);
    reader.delete(new Term("city", "beijing"));
    reader.close();
    IndexWriter writer = new IndexWriter(indexDir, new StandardAnalyzer(), true);
    writer.optimize();
    writer.close();
  }

5,把RAMDirectory中的索引合并到FSDirectroy中

 
  public void indexOperator(String indexDir) throws Exception {
    FSDirectory fsDir = FSDirectory.getDirectory(indexDir, true);
    RAMDirectory ramDir = new RAMDirectory();
    IndexWriter fsWriter = new IndexWriter(fsDir, new SimpleAnalyzer(), true);
    IndexWriter ramWriter = new IndexWriter(ramDir, new SimpleAnalyzer(), true);
    // ..ramWriter add doc
    fsWriter.addIndexes(new Directory[] { ramDir });
    ramWriter.close();
  }

6,把索引的内容直接读入内存

 
RAMDirectory ramDir = new RAMDirectory(indexDir);