2010-10-24 73 views
0

我想问一下这个源代码中System.property的用法是什么?我找不到确切的答案。System.property是什么意思?

public abstract class BaseIndexingTestCase extends TestCase { 
protected String[] keywords = {"1", "2"}; 
protected String[] unindexed = {"Netherlands", "Italy"}; 
protected String[] unstored = {"Amsterdam has lots of bridges", 
"Venice has lots of canals"}; 
protected String[] text = {"Amsterdam", "Venice"}; 
protected Directory dir; 
protected void setUp() throws IOException { 
String indexDir = 
System.getProperty("java.io.tmpdir", "tmp") + 
System.getProperty("file.separator") + "index-dir"; 
dir = FSDirectory.getDirectory(indexDir, true); 
addDocuments(dir); 
} 
protected void addDocuments(Directory dir) 
throws IOException { 
IndexWriter writer = new IndexWriter(dir, getAnalyzer(), 
true); 
writer.setUseCompoundFile(isCompound()); 
for (int i = 0; i < keywords.length; i++) { 
Document doc = new Document(); 
doc.add(Field.Keyword("id", keywords[i])); 
doc.add(Field.UnIndexed("country", unindexed[i])); 
doc.add(Field.UnStored("contents", unstored[i])); 
doc.add(Field.Text("city", text[i])); 
writer.addDocument(doc); 
} 
writer.optimize(); 
writer.close(); 
} 
protected Analyzer getAnalyzer() { 
return new SimpleAnalyzer(); 
} 
protected boolean isCompound() { 
return true; 
} 
} 

这是混淆了我的界限。

System.getProperty("java.io.tmpdir", "tmp") + 
System.getProperty("file.separator") + "index-dir"; 

回答

1

我觉得这

String indexDir = 
System.getProperty("java.io.tmpdir", "tmp") + 
System.getProperty("file.separator") + "index-dir"; 

创建一个文件夹systemtempdir /索引目录或TMP /索引目录。如果一个临时目录中没有propertyentry已经找到。

2

System.getProperty(..)电话是有为了获得temp目录的操作系统:

  • java.io.tmpdir是临时目录
  • file.separator是特定于操作系统的文件分隔符 - 无论是/\