如何将异常堆栈跟踪插入日志

Question

i have code like this:

catch (Exception ex) {
            // Log the error
            ex.printStackTrace();
            logger.error("Error in Best Quote Thread: " +  ex); 
        }

yes i got the error in my log like this: 2020-12-07 11:27:56 ERROR FixProtocolConvert:162 - Error in Fix Protocol Convert Thread: java.lang.NullPointerException

}catch (Exception ex) {
            // Log the error
            ex.printStackTrace();
            logger.error("Error in FixProtocolConvert: " ,  ex); 
        }

i also have to try use this code but i only get like this: 2020-12-07 14:09:52 ERROR FixProtocolConvert:325 - Error in Fix Protocol Convert Thread: java.lang.NullPointerException java.lang.NullPointerException

how to get exactly position of this error? like this example of ex.printstacktrace. so i need to log the value of ex.printstacktrace to my logger

com.abcd.core.datafeed.fixProtocol(FixProtocolConvert.java:121)
        at 

my question is how to get exactly position of this error? because if i use that code only get log like that... thanks all

Answer 1

The last parameter passed to any log method ( info , warn , ...) will be interpreted as Exception if it is an appropriate subclass.

try {
    operationThatCanFail();
catch (Exception e) {
    LOG.error("Operation failed", e); // <-- exception passed as last param 
}

If you need to use additional parameters:

try {
    operationThatCanFail();
catch (Exception e) {
    LOG.error("First {} Third {}", "Second", "Fourth", e);
}

Also, don´t use e.printStackTrace() together with a Logger . It is sufficient to use one form of logging. Prefer using a Logger instead of System.err , which is used by printStackTrace() .

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