java - finally 在嵌套的 try/catch 中放在哪里？

Question

finally 如何在嵌套的 try/catch 中工作？
例如。对于:

try{  
//code

}  
catch(SomeException e){  
   //code  
   try{  
      //code  
   }  
   catch(OtherException e){  
     //code  
   }  
}  
catch(SomeOtherException e){    
  //code  
} 

放置finally 的最佳位置在哪里？或者我应该把它放在嵌套和外部 try 中吗？

Answer 1

如果您希望 finally block 中的代码无论在任何一个 block 中发生什么都运行，请将其放在外部 try 中。如果您只希望它在第一个 try block 中无论发生什么 都运行，请将其放在那里:

try{  // try/catch #1
  //code block #1

}  
catch(SomeException e){  

   //code block #2

   try{  // try/catch #2
      //code block #3
   }  
   catch(OtherException e){  
     //code block #4
   }  
   finally {
     // This code runs no matter what happens with try/catch #2 (so
     // after code block #3 and/or #4, depending on whether there's
     // an exception). It does NOT run after code block #1 if that
     // block doesn't throw, does NOT run after code block #2 if
     // that block DOES throw), and does not run if code block #1
     // throws SomeOtherException (code block #5).
   }
}  
catch(SomeOtherException e){    
  //code block #5
} 
finally {
  // This code runs no matter what happens with EITHER
  // try/catch #1 or try/catch #2, no matter what happens
  // with any of the code blocks above, 1-5
}

更简单地说:

try {
   // covered by "outer" finally
}
catch (Exception1 ex) {
   // covered by "outer" finally

   try {
     // Covered by both "inner" and "outer" finallys
   }
   catch (Exception2 ex) {
     // Covered by both "inner" and "outer" finallys
   }
   catch (Exception3 ex) {
     // Covered by both "inner" and "outer" finallys
   }
   finally { // "inner" finally
   }
}
catch (Exception4 ex) {
   // covered by "outer" finally
}
finally { // "outer" finally
}