[hyddd的FindBugs分析记录][M X OBL] Method may fail to clean up stream or resource

[M X OBL] Method may fail to clean up stream or resource [OBL_UNSATISFIED_OBLIGATION]

This method may fail to clean up (close, dispose of) a stream, database object, or other resource requiring an explicit cleanup operation.

In general, if a method opens a stream or other resource, the method should use a try/finally block to ensure that the stream or resource is cleaned up before the method returns.

This bug pattern is essentially the same as the OS_OPEN_STREAM and ODR_OPEN_DATABASE_RESOURCE bug patterns, but is based on a different (and hopefully better) static analysis technique. We are interested is getting feedback about the usefulness of this bug pattern. To send feedback, either:

• send email to findbugs@cs.umd.edu
• file a bug report: http://findbugs.sourceforge.net/reportingBugs.html

In particular, the false-positive suppression heuristics for this bug pattern have not been extensively tuned, so reports about false positives are helpful to us.

See Weimer and Necula, Finding and Preventing Run-Time Error Handling Mistakes, for a description of the analysis technique.

 

这个BUG想说明的是：有些资源打开了，但在函数结束的时候却没有关闭。比如：数据库连接......

虽然JAVA有垃圾回收机制，但是，自己打开的资源需要自己手动关闭，否则有可能直到程序退出，JRE才会清理你打开的资源。这里FindBugs建议在try/finally里面关闭打开的资源，在关闭之前，还要判断资源是否为Null，或者再加一层异常捕获处理噢～

以下是一些可能关闭资源失败的例子：

-----------------------------------------------情况1-----------------------------------------

//
FileOutputStream fs = null;
try{
　　fs = new FileOutputStream(clearTableFile);
　　fs.close();    //当出异常时候fs关闭失败，所以应该在finally中关闭
}
catch(){
//
}

-----------------------------------------------情况2-----------------------------------------

//
Properties props = new Properties();
try{
　　props.store(new FileOutputStream(configFile), configFile);　　//new FileOutputStream(configFile)没有释放。
}
catch(){
　　//
}

-----------------------------------------------情况3-----------------------------------------

　　//
　　FileOutputStream fs = new FileOutputStream(clearTableFile);
　　//    (里没有做异常处理，如果中间出异常了，异常会抛往上层，这时fs就没能释放了。
　　fs.close();    
　　//