add SimpleApolloConfigDemo

apollo-demo/src/main/java/SimpleApolloConfigDemo.java

+import com.google.common.base.Charsets;
+
+import com.ctrip.framework.apollo.Config;
+import com.ctrip.framework.apollo.ConfigChangeListener;
+import com.ctrip.framework.apollo.ConfigService;
+import com.ctrip.framework.apollo.model.ConfigChange;
+import com.ctrip.framework.apollo.model.ConfigChangeEvent;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class SimpleApolloConfigDemo {
+  private static final Logger logger = LoggerFactory.getLogger(SimpleApolloConfigDemo.class);
+  private String DEFAULT_VALUE = "undefined";
+  private Config config;
+
+  public SimpleApolloConfigDemo() {
+    ConfigChangeListener changeListener = new ConfigChangeListener() {
+      @Override
+      public void onChange(ConfigChangeEvent changeEvent) {
+        logger.info("Changes for namespace {}", changeEvent.getNamespace());
+        for (String key : changeEvent.changedKeys()) {
+          ConfigChange change = changeEvent.getChange(key);
+          logger.info("Change - key: {}, oldValue: {}, newValue: {}, changeType: {}",
+              change.getPropertyName(), change.getOldValue(), change.getNewValue(),
+              change.getChangeType());
+        }
+      }
+    };
+    config = ConfigService.getAppConfig();
+    config.addChangeListener(changeListener);
+  }
+
+  private String getConfig(String key) {
+    String result = config.getProperty(key, DEFAULT_VALUE);
+    logger.info(String.format("Loading key : %s with value: %s", key, result));
+    return result;
+  }
+
+  public static void main(String[] args) throws IOException {
+    SimpleApolloConfigDemo apolloConfigDemo = new SimpleApolloConfigDemo();
+    System.out.println(
+        "Apollo Config Demo. Please input key to get the value. Input quit to exit.");
+    while (true) {
+      System.out.print("> ");
+      String input = new BufferedReader(new InputStreamReader(System.in, Charsets.UTF_8)).readLine();
+      if (input == null || input.length() == 0) {
+        continue;
+      }
+      input = input.trim();
+      if (input.equalsIgnoreCase("quit")) {
+        System.exit(0);
+      }
+      apolloConfigDemo.getConfig(input);
+    }
+  }
+}