Cum se generează o excepție de timeout simplă în Java?

Publicat: 2018-02-26

Java - Cum se generează o excepție de timeout simplă

În Java, cum se generează TimeoutException simplă?

În acest tutorial vom genera o eroare Timeout apelând Google.com cu o întârziere simplă de 10 milisecunde. CrunchifyGenerateTimeout este un apel public în care apelăm google.com folosind 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 ( ) ;
}
}
}
}
}

Doar rulați programul de mai sus ca aplicație Java și veți putea genera TimeoutException în consola Eclipse.

Dacă creșteți ReadTimeout la 1000 de milisecunde, atunci nu veți putea regenera excepția.

// 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)