Come generare un'eccezione di timeout semplice in Java?

Pubblicato: 2018-02-26

Java - Come generare un'eccezione di timeout semplice

In Java come generare una semplice TimeoutException?

In questo tutorial genereremo un errore di timeout chiamando Google.com con un semplice ritardo di 10 millisecondi. CrunchifyGenerateTimeout è una chiamata pubblica in cui chiamiamo google.com utilizzando connection.connect() .

CrunchifyGenerateTimeout.java
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package crunchify . com . tutorial ;
 
import java . io . BufferedReader ;
import java . io . IOException ;
import java . io . InputStreamReader ;
import java . net . HttpURLConnection ;
import java . net . URL ;
 
/**
* @author Crunchify.com
* Program: How to Generate Simple TimeoutException for a specific IP in Java
* Version: 1.0.1
*
*/
 
public class CrunchifyGenerateTimeout {
 
public static void main ( String [ ] args ) throws Exception {
new CrunchifyGenerateTimeout ( ) ;
}
 
public CrunchifyGenerateTimeout ( ) {
try {
String myUrl = "https://google.com/" ;
 
// myUrl = URLEncoder.encode(myUrl, "UTF-8");
 
String results = crunchifyCallURL ( myUrl ) ;
 
System . out . println ( results ) ;
} catch ( Exception e ) {
 
e . printStackTrace ( ) ;
}
}
 
/**
* Just return a result of URL call.
*
* @param crunchifyURL
* @return
* @throws Exception
*/
private String crunchifyCallURL ( String crunchifyURL ) throws Exception {
URL crunchURL = null ;
BufferedReader crunchReader = null ;
StringBuilder crunchBuilder ;
 
try {
// create the HttpURLConnection
crunchURL = new URL ( crunchifyURL ) ;
HttpURLConnection connection = ( HttpURLConnection ) crunchURL . openConnection ( ) ;
 
// Let's make GET call
connection . setRequestMethod ( "GET" ) ;
 
// Current Timeout 10 milliseconds - to generate Timeout Error
connection . setReadTimeout ( 10 ) ;
connection . connect ( ) ;
 
// Simply read result and print line
crunchReader = new BufferedReader ( new InputStreamReader ( connection . getInputStream ( ) ) ) ;
crunchBuilder = new StringBuilder ( ) ;
 
String eachLine = null ;
while ( ( eachLine = crunchReader . readLine ( ) ) ! = null ) {
crunchBuilder . append ( eachLine + "\n" ) ;
}
return crunchBuilder . toString ( ) ;
 
} catch ( Exception et ) {
et . printStackTrace ( ) ;
throw et ;
} finally {
if ( crunchReader ! = null ) {
try {
crunchReader . close ( ) ;
} catch ( IOException ioException ) {
ioException . printStackTrace ( ) ;
}
}
}
}
}

Basta eseguire il programma sopra come applicazione Java e sarai in grado di generare TimeoutException nella console Eclipse.

Se aumenti ReadTimeout a 1000 millisecondi, non sarai in grado di rigenerare l'eccezione.

// connection .setReadTimeout(1000);

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java.net.SocketTimeoutException: Read timed out
at java.base/java.net.SocketInputStream.socketRead0(Native Method)
at java.base/java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.base/java.net.SocketInputStream.read(SocketInputStream.java:171)
at java.base/java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.base/sun.security.ssl.SSLSocketInputRecord.read(SSLSocketInputRecord.java:425)
at java.base/sun.security.ssl.SSLSocketInputRecord.decode(SSLSocketInputRecord.java:154)
at java.base/sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1031)
at java.base/sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:973)
at java.base/sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1402)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1429)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
at java.base/sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:567)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:163)
at crunchify.com.tutorial.CrunchifyGenerateTimeout.doHttpUrlConnectionAction(CrunchifyGenerateTimeout.java:60)
at crunchify.com.tutorial.CrunchifyGenerateTimeout.<init>(CrunchifyGenerateTimeout.java:29)
at crunchify.com.tutorial.CrunchifyGenerateTimeout.main(CrunchifyGenerateTimeout.java:20)
java.net.SocketTimeoutException: Read timed out
at java.base/java.net.SocketInputStream.socketRead0(Native Method)
at java.base/java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.base/java.net.SocketInputStream.read(SocketInputStream.java:171)
at java.base/java.net.SocketInputStream.read(SocketInputStream.java:141)
at java.base/sun.security.ssl.SSLSocketInputRecord.read(SSLSocketInputRecord.java:425)
at java.base/sun.security.ssl.SSLSocketInputRecord.decode(SSLSocketInputRecord.java:154)
at java.base/sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1031)
at java.base/sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:973)
at java.base/sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1402)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1429)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
at java.base/sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:567)
at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.connect(HttpsURLConnectionImpl.java:163)
at crunchify.com.tutorial.CrunchifyGenerateTimeout.doHttpUrlConnectionAction(CrunchifyGenerateTimeout.java:60)
at crunchify.com.tutorial.CrunchifyGenerateTimeout.<init>(CrunchifyGenerateTimeout.java:29)
at crunchify.com.tutorial.CrunchifyGenerateTimeout.main(CrunchifyGenerateTimeout.java:20)