log4j example

This Example shows you how to create a log in a Servlet.

Description of the code:

Logger.getLogger(): Logger class is used for handling the majority of log operations and getLogger method is used for return a logger according to the value of the parameter. If the logger already exists, then the existing instance will be returned. If the logger is not already exist, then create a new instance.

log.info(): This method is used to check that the specified category is INFO enabled or not, if yes then it converts the massage passed as a string argument to a string by using appropriate object renderer of class ObjectRenderer.

log4jexample.java




import org.apache.log4j.Logger;



class CustomerOrder {



    private String productName;

    private int productCode;

    private int productPrice;



    public int getProductCode() {

        return productCode;

    }



    public void setProductCode(int productCode) {

        this.productCode = productCode;

    }



    public String getProductName() {

        return productName;

    }



    public void setProductName(String productName) {

        this.productName = productName;

    }



    public int getProductPrice() {

        return productPrice;

    }



    public void setProductPrice(int productPrice) {

        this.productPrice = productPrice;

    }



    public CustomerOrder(String productName, int productCode,

int productPrice) {

this.productName = productName; this.productCode = productCode; this.productPrice = productPrice; } } public class Log4jExample { private static Logger logger = Logger.getLogger("name"); public void processOrder(CustomerOrder order) { logger.info(order.getProductName()); } public static void main(String args[]) { CustomerOrder order1 = new CustomerOrder("Beer", 101, 20); CustomerOrder order2 = new CustomerOrder("Lemonade", 95, 10); CustomerOrder order3 = new CustomerOrder("Chocolate", 223, 5); Log4jExample demo = new Log4jExample(); demo.processOrder(order1); demo.processOrder(order2); demo.processOrder(order3); } }

log4j.properties



log4j.rootLogger=debug, stdout

log4j.appender.stdout=org.apache.log4j.ConsoleAppender

log4j.appender.stdout.Target=System.out

log4j.appender.stdout.layout=org.apache.log4j.PatternLayout

log4j.appender.stdout.layout.ConversionPattern=%t %-5p %c{2} - %m%n

Output:




main INFO  name - Beer

main INFO  name - Lemonade

main INFO  name - Chocolate

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