The method isNullOrEmpty(String) is undefined for the type StringUtils

Question

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.log4j.MDC;
import java.util.UUID;

import org.springframework.util.StringUtils;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

/**
 * A webflow request interceptor injecting correlation id to the request context.
 */
public class TestController extends HandlerInterceptorAdapter {

    private static final String CORRELATION_ID_HEADER_NAME = "X-Correlation-Id";
    private static final String CORRELATION_ID_LOG_VAR_NAME = "correlationId";

    @Override
    public boolean preHandle(final HttpServletRequest request, final HttpServletResponse response,
                             final Object handler) throws Exception {
        final String correlationId = getCorrelationIdFromHeader(request);
        MDC.put(CORRELATION_ID_LOG_VAR_NAME, correlationId);
        return true;
    }

    @Override
    public void afterCompletion(final HttpServletRequest request, final HttpServletResponse response,
                             final Object handler, final Exception ex) throws Exception {
        MDC.remove(CORRELATION_ID_LOG_VAR_NAME);
    }

    private String getCorrelationIdFromHeader(final HttpServletRequest request) {
        String correlationId = request.getHeader(CORRELATION_ID_HEADER_NAME);
        ***if (StringUtils.isNullOrEmpty(correlationId)) {***
            correlationId = generateUniqueCorrelationId();
        }
        return correlationId;
    }

    private String generateUniqueCorrelationId() {
        return UUID.randomUUID().toString();
    }
}

i tried to run this program but the error comes can u help me? i am learning correlation ID on logging but cant find the right and good source then i found site which show this code can someone help:)

P.S the error is The method isNullOrEmpty(String) is undefined for the type StringUtils.. on the line where i give *** on the code above

Answer 1

You are using org.springframework.util.StringUtils which has a method isEmpty(value). However, you probably want Apache's Commons Lang which has a much more complete StringUtils.