init config client implementation and added a demo project using it.

apollo-client/pom.xml

 <?xml version="1.0"  encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
-	<parent>
-		<groupId>com.ctrip.apollo</groupId>
-		<artifactId>apollo</artifactId>
-		<version>0.0.1</version>
-		<relativePath>../pom.xml</relativePath>
-	</parent>
-	<modelVersion>4.0.0</modelVersion>
-	<artifactId>apollo-client</artifactId>
-	<name>Apollo Client</name>
-	<dependencies>
-		<dependency>
-			<groupId>com.ctrip.apollo</groupId>
-			<artifactId>apollo-core</artifactId>
-		</dependency>
-	</dependencies>
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <parent>
+        <groupId>com.ctrip.apollo</groupId>
+        <artifactId>apollo</artifactId>
+        <version>0.0.1</version>
+        <relativePath>../pom.xml</relativePath>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>apollo-client</artifactId>
+    <name>Apollo Client</name>
+    <dependencies>
+        <!-- apollo -->
+        <dependency>
+            <groupId>com.ctrip.apollo</groupId>
+            <artifactId>apollo-core</artifactId>
+        </dependency>
+        <!-- end of apollo -->
+        <!-- spring -->
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-context</artifactId>
+        </dependency>
+        <!-- end of spring -->
+        <!-- util -->
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+        </dependency>
+        <!-- end of util -->
+        <!-- test -->
+        <dependency>
+            <groupId>commons-logging</groupId>
+            <artifactId>commons-logging</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <!-- end of test -->
+    </dependencies>
 </project>

apollo-client/src/main/java/com/ctrip/apollo/client/ApolloConfig.java

+package com.ctrip.apollo.client;
+
+import com.ctrip.apollo.client.loader.ConfigLoader;
+import com.ctrip.apollo.client.loader.ConfigLoaderFactory;
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.BeanDefinitionRegistry;
+import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.Ordered;
+import org.springframework.core.PriorityOrdered;
+import org.springframework.core.env.CompositePropertySource;
+import org.springframework.core.env.MutablePropertySources;
+
+/**
+ * Client side config
+ *
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class ApolloConfig implements BeanDefinitionRegistryPostProcessor, PriorityOrdered, ApplicationContextAware {
+    public static final String APOLLO_PROPERTY_SOURCE_NAME = "ApolloConfigProperties";
+
+    private ConfigLoader configLoader;
+
+    private ConfigurableApplicationContext applicationContext;
+
+    public ApolloConfig() {
+        this.configLoader = ConfigLoaderFactory.getInstance().getMockConfigLoader();
+    }
+
+    @Override
+    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
+        if (!(applicationContext instanceof ConfigurableApplicationContext)) {
+            throw new RuntimeException(
+                    String.format("ApplicationContext must implement ConfigurableApplicationContext, but found: %s", applicationContext.getClass().getName()));
+        }
+        this.applicationContext = (ConfigurableApplicationContext) applicationContext;
+    }
+
+    /**
+     * This is the first method invoked, so we could prepare the property sources here
+     */
+    @Override
+    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
+        preparePropertySource();
+    }
+
+    /**
+     * This is executed after postProcessBeanDefinitionRegistry
+     */
+    @Override
+    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
+    }
+
+    @Override
+    public int getOrder() {
+        return Ordered.HIGHEST_PRECEDENCE + 1;
+    }
+
+    void preparePropertySource() {
+        MutablePropertySources currentPropertySources = applicationContext.getEnvironment().getPropertySources();
+        if (currentPropertySources.contains(APOLLO_PROPERTY_SOURCE_NAME)) {
+            currentPropertySources.remove(APOLLO_PROPERTY_SOURCE_NAME);
+        }
+
+        CompositePropertySource composite = new CompositePropertySource(APOLLO_PROPERTY_SOURCE_NAME);
+        composite.addPropertySource(configLoader.loadPropertySource());
+        currentPropertySources.addFirst(composite);
+    }
+}

apollo-client/src/main/java/com/ctrip/apollo/client/loader/ConfigLoader.java

+package com.ctrip.apollo.client.loader;
+
+import org.springframework.core.env.CompositePropertySource;
+
+/**
+ * @author Jason Song(songs_ctrip.com)
+ */
+public interface ConfigLoader {
+    /**
+     * Load property source for client use
+     * @return property source
+     */
+    CompositePropertySource loadPropertySource();
+}

apollo-client/src/main/java/com/ctrip/apollo/client/loader/ConfigLoaderFactory.java

+package com.ctrip.apollo.client.loader;
+
+import com.ctrip.apollo.client.loader.impl.MockConfigLoader;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class ConfigLoaderFactory {
+    private static ConfigLoaderFactory configLoaderFactory = new ConfigLoaderFactory();
+
+    private ConfigLoaderFactory() {
+    }
+
+    public static ConfigLoaderFactory getInstance() {
+        return configLoaderFactory;
+    }
+
+    public ConfigLoader getMockConfigLoader() {
+        return new MockConfigLoader();
+    }
+}

apollo-client/src/main/java/com/ctrip/apollo/client/loader/impl/LocalConfigLoader.java

+package com.ctrip.apollo.client.loader.impl;
+
+import com.ctrip.apollo.client.loader.ConfigLoader;
+import org.springframework.core.env.CompositePropertySource;
+
+/**
+ * Load config from local backup file
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class LocalConfigLoader implements ConfigLoader {
+    private static final String PROPERTY_SOURCE_NAME = "ApolloLocalConfigProperties";
+
+    @Override
+    public CompositePropertySource loadPropertySource() {
+        return null;
+    }
+}

apollo-client/src/main/java/com/ctrip/apollo/client/loader/impl/MockConfigLoader.java

+package com.ctrip.apollo.client.loader.impl;
+
+import com.ctrip.apollo.client.loader.ConfigLoader;
+import com.google.common.collect.Maps;
+import org.springframework.core.env.CompositePropertySource;
+import org.springframework.core.env.MapPropertySource;
+
+import java.util.Map;
+
+/**
+ * Mock config
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class MockConfigLoader implements ConfigLoader {
+    private static final String PROPERTY_SOURCE_NAME = "ApolloMockConfigProperties";
+
+    @Override
+    public CompositePropertySource loadPropertySource() {
+        CompositePropertySource composite = new CompositePropertySource(PROPERTY_SOURCE_NAME);
+        composite.addPropertySource(mock());
+        return composite;
+    }
+
+    private MapPropertySource mock() {
+        Map<String, Object> source = Maps.newHashMap();
+        source.put("apollo.foo" ,"bar");
+        MapPropertySource propertySource = new MapPropertySource("mock source", source);
+
+        return propertySource;
+    }
+}

apollo-client/src/main/java/com/ctrip/apollo/client/loader/impl/RemoteConfigLoader.java

+package com.ctrip.apollo.client.loader.impl;
+
+import com.ctrip.apollo.client.loader.ConfigLoader;
+import org.springframework.core.env.CompositePropertySource;
+
+/**
+ * Load config from remote config server
+ * @author Jason Song(song_s@ctrip.com)
+ */
+public class RemoteConfigLoader implements ConfigLoader {
+    private static final String PROPERTY_SOURCE_NAME = "ApolloRemoteConfigProperties";
+
+    @Override
+    public CompositePropertySource loadPropertySource() {
+        return null;
+    }
+}

apollo-client/src/test/java/com/ctrip/apollo/client/ApolloConfigTest.java

+package com.ctrip.apollo.client;
+
+import com.ctrip.apollo.client.loader.ConfigLoader;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+import org.springframework.context.ApplicationContext;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.env.CompositePropertySource;
+import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.MutablePropertySources;
+import org.springframework.test.util.ReflectionTestUtils;
+
+import static org.mockito.Mockito.*;
+import static org.junit.Assert.*;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class ApolloConfigTest {
+    private ApolloConfig apolloConfig;
+    @Mock
+    private ConfigLoader configLoader;
+    @Mock
+    private ConfigurableApplicationContext applicationContext;
+    @Mock
+    private ConfigurableEnvironment env;
+    @Mock
+    private MutablePropertySources mutablePropertySources;
+
+    @Before
+    public void setUp() {
+        apolloConfig = new ApolloConfig();
+
+        when(applicationContext.getEnvironment()).thenReturn(env);
+        when(env.getPropertySources()).thenReturn(mutablePropertySources);
+
+        apolloConfig.setApplicationContext(applicationContext);
+        ReflectionTestUtils.setField(apolloConfig, "configLoader", configLoader);
+    }
+
+    @Test(expected = RuntimeException.class)
+    public void testInvalidApplicationContext() {
+        ApplicationContext someInvalidApplication = mock(ApplicationContext.class);
+        apolloConfig.setApplicationContext(someInvalidApplication);
+    }
+
+    @Test
+    public void testPreparePropertySourceSuccessful() {
+        CompositePropertySource somePropertySource = mock(CompositePropertySource.class);
+        final ArgumentCaptor<CompositePropertySource> captor = ArgumentCaptor.forClass(CompositePropertySource.class);
+
+        when(configLoader.loadPropertySource()).thenReturn(somePropertySource);
+
+        apolloConfig.preparePropertySource();
+
+        verify(configLoader, times(1)).loadPropertySource();
+        verify(mutablePropertySources, times(1)).addFirst(captor.capture());
+
+        final CompositePropertySource insertedPropertySource = captor.getValue();
+
+        assertEquals(ApolloConfig.APOLLO_PROPERTY_SOURCE_NAME, insertedPropertySource.getName());
+        assertTrue(insertedPropertySource.getPropertySources().contains(somePropertySource));
+    }
+
+}

apollo-demo/pom.xml

+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <parent>
+        <artifactId>apollo</artifactId>
+        <groupId>com.ctrip.apollo</groupId>
+        <version>0.0.1</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>apollo-demo</artifactId>
+    <packaging>war</packaging>
+    <name>Apollo Demo</name>
+    <url>http://maven.apache.org</url>
+    <dependencies>
+        <dependency>
+            <groupId>com.ctrip.apollo</groupId>
+            <artifactId>apollo-client</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-webmvc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.tuckey</groupId>
+            <artifactId>urlrewritefilter</artifactId>
+            <version>4.0.4</version>
+        </dependency>
+        <dependency>
+            <groupId>javax.servlet</groupId>
+            <artifactId>jstl</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>commons-logging</groupId>
+            <artifactId>commons-logging</artifactId>
+        </dependency>
+    </dependencies>
+    <build>
+        <finalName>apollo-demo</finalName>
+    </build>
+</project>

apollo-demo/src/main/java/com/ctrip/apollo/demo/AppConfig.java

+package com.ctrip.apollo.demo;
+
+import com.ctrip.apollo.client.ApolloConfig;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.ComponentScan;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.support.PropertySourcesPlaceholderConfigurer;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+@Configuration
+@ComponentScan(value = "com.ctrip.apollo.demo")
+public class AppConfig {
+    @Bean
+    public ApolloConfig apolloConfig() {
+        return new ApolloConfig();
+    }
+
+    @Bean
+    public PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer() {
+        return new PropertySourcesPlaceholderConfigurer();
+    }
+}

apollo-demo/src/main/java/com/ctrip/apollo/demo/DemoController.java

+package com.ctrip.apollo.demo;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.core.env.Environment;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+@RestController
+@RequestMapping("/demo")
+public class DemoController {
+    @Autowired
+    private Environment env;
+
+    @Value("${apollo.foo}")
+    private String foo;
+
+    @RequestMapping(value = "/config/{configName:.*}", method = RequestMethod.GET)
+    public String queryConfig(@PathVariable String configName) {
+        return env.getProperty(configName, "undefined");
+    }
+}

apollo-demo/src/main/java/com/ctrip/apollo/demo/WebConfig.java

+package com.ctrip.apollo.demo;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
+import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
+import org.springframework.web.servlet.view.InternalResourceViewResolver;
+import org.springframework.web.servlet.view.JstlView;
+
+/**
+ * @author Jason Song(song_s@ctrip.com)
+ */
+@Configuration
+@EnableWebMvc
+public class WebConfig extends WebMvcConfigurerAdapter {
+    @Override
+    public void addViewControllers(ViewControllerRegistry registry) {
+        registry.addViewController("/").setViewName("welcome");
+        registry.addViewController("/index").setViewName("welcome");
+    }
+
+    @Bean
+    public InternalResourceViewResolver viewResolver() {
+        InternalResourceViewResolver viewResolver
+                = new InternalResourceViewResolver();
+        viewResolver.setViewClass(JstlView.class);
+        viewResolver.setPrefix("/WEB-INF/views/");
+        viewResolver.setSuffix(".jsp");
+        return viewResolver;
+    }
+
+    @Override
+    public void addResourceHandlers(ResourceHandlerRegistry registry) {
+        registry.addResourceHandler("/**").addResourceLocations("/");
+    }
+}

apollo-demo/src/main/webapp/WEB-INF/urlrewrite.xml

+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE urlrewrite PUBLIC "-//tuckey.org//DTD UrlRewrite 3.0//EN" "http://tuckey.org/res/dtds/urlrewrite3.0.dtd">
+<urlrewrite default-match-type="wildcard">
+    <rule>
+        <from>/favicon.ico</from>
+        <to>/s/favicon.ico</to>
+    </rule>
+    <rule>
+        <from>/images/**</from>
+        <to>/s/images/$1</to>
+    </rule>
+    <rule>
+        <from>/scripts/**</from>
+        <to>/s/scripts/$1</to>
+    </rule>
+    <rule>
+        <from>/styles/**</from>
+        <to>/s/styles/$1</to>
+    </rule>
+    <rule>
+        <from>/templates/**</from>
+        <to>/s/templates/$1</to>
+    </rule>
+    <rule match-type="regex">
+        <from>^\/(index\..*)?</from>
+        <to>/app/</to>
+    </rule>
+    <rule>
+        <from>/**</from>
+        <to>/app/$1</to>
+    </rule>
+    <outbound-rule>
+        <from>/app/**</from>
+        <to>/$1</to>
+    </outbound-rule>
+</urlrewrite>

apollo-demo/src/main/webapp/WEB-INF/views/welcome.jsp

+<html>
+<body>
+<h2>Hello World!</h2>
+</body>
+</html>

apollo-demo/src/main/webapp/WEB-INF/web.xml

+<!DOCTYPE web-app PUBLIC
+        "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
+        "http://java.sun.com/dtd/web-app_2_3.dtd" >
+
+<web-app>
+    <display-name>Apollo demo</display-name>
+    <!-- Enables clean URLs with JSP views e.g. /welcome instead of /app/welcome -->
+    <filter>
+        <filter-name>UrlRewriteFilter</filter-name>
+        <filter-class>org.tuckey.web.filters.urlrewrite.UrlRewriteFilter</filter-class>
+    </filter>
+    <filter-mapping>
+        <filter-name>UrlRewriteFilter</filter-name>
+        <url-pattern>/*</url-pattern>
+    </filter-mapping>
+    <servlet>
+        <servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
+        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
+        <init-param>
+            <param-name>contextClass</param-name>
+            <param-value>
+                org.springframework.web.context.support.AnnotationConfigWebApplicationContext
+            </param-value>
+        </init-param>
+        <init-param>
+            <param-name>contextConfigLocation</param-name>
+            <param-value>
+                com.ctrip.apollo.demo.AppConfig
+            </param-value>
+        </init-param>
+        <load-on-startup>1</load-on-startup>
+    </servlet>
+    <servlet-mapping>
+        <servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
+        <url-pattern>/app/*</url-pattern>
+    </servlet-mapping>
+</web-app>

pom.xml

@@ -70,6 +70,7 @@
 		<module>apollo-configserver</module>
 		<module>apollo-portal</module>
 		<module>apollo-assembly</module>
+		<module>apollo-demo</module>
 	</modules>
 	<dependencyManagement>
 		<dependencies>
@@ -97,9 +98,9 @@
 			</dependency>
 			<!-- declare Spring BOMs in order -->
 			<dependency>
-				<groupId>org.springframework.boot</groupId>
-				<artifactId>spring-boot-starter-parent</artifactId>
-				<version>1.3.3.RELEASE</version>
+				<groupId>io.spring.platform</groupId>
+				<artifactId>platform-bom</artifactId>
+				<version>2.0.3.RELEASE</version>
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>