Shulou(Shulou.com)06/03 Report--

This article will explain in detail how the new abnormal feature mutilcatch of Java 7 is, and the content of the article is of high quality, so the editor will share it with you for reference. I hope you will have some understanding of the relevant knowledge after reading this article.

Java7 enhances the exception handling mechanism of Java, which is mainly manifested in three aspects: catching multiple exception types (multicatch), rethrowing (rethrow) exceptions, and simplifying resource cleanup (try-with-resources)

Catch multiple exception types

Starting with Java7, you can catch multiple types of exceptions in a single catch block. The main purpose of adding the features of multicatch is to reduce repetitive code and less extensive exception catch (such as the catch catch (Exception e)).

If you are developing an application that has the flexibility to copy data to a database or file, listing 1 (CopyToDatabaseOrFile.java) simulates this program, showing that there is code duplication in the catch module:

Java code

/ / CopyToDatabaseOrFile.java import java.io.IOException; import java.sql.SQLException; public class CopyToDatabaseOrFile {public static void main (String [] args) {try {copy ();} catch (IOException ex) {System.out.println (ex.getMessage ()) / / additional handler code} catch (SQLException ex) {System.out.println (ex.getMessage ()); / / additional handler code that's identical to the previous handler's / / code}} static void copy () throws IOException, SQLException {if (Math.random () < 0.5) throw new IOException ("cannot copy to file") Else throw new SQLException ("cannot copy to database");}}

Listing 1: CopyToDatabaseOrFile.java

Java7 overcomes this problem of code duplication. You only need to specify multiple exceptions to be handled in a catch block, arrange the exceptions in order, and separate each exception with a "|". Such as:

Java code

Try {copy ();} catch (IOException | SQLException ex) {System.out.println (ex.getMessage ());}

Now, when the copy () method throws any type, it is caught in the catch block.

When multiple exceptions are declared in catch, the declared exception defaults to final, which means that the reference to the exception can no longer be modified. As in the example above, you can no longer assign ex to another exception (such as ex=new MyException ()).

So much for sharing about the unusual new feature mutilcatch of Java 7. I hope the above content can be of some help and learn more knowledge. If you think the article is good, you can share it for more people to see.

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