动态classpath property文件扫描、加载实现

PluginModuleLoader.java

package test;

import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;

/**
 * ocean模块化插件加载、管理类, 均为静态方法
 * 
 * @author pf-miles
 * @since 2014-11-13
 */
@SuppressWarnings("unchecked")
public abstract class PluginModuleLoader {

    private static final Map<String, List<String>> props = new HashMap<String, List<String>>();
    static {
        // 尝试加载所有classpath中插件的配置
        try {
            Enumeration<URL> reses = Thread.currentThread().getContextClassLoader().getResources("META-INF/ocean-ext.properties");
            if (reses != null && reses.hasMoreElements()) {
                while (reses.hasMoreElements()) {
                    PropertiesConfiguration conf = new PropertiesConfiguration();
                    URL url = reses.nextElement();
                    try {
                        conf.load(url.openStream(), "UTF-8");
                        for (PluginConf k : PluginConf.values()) {
                            if (k.isMultiValue()) {
                                List<String> vals = (List<String>) conf.getList(k.getKey());
                                if (vals != null && !vals.isEmpty()) {
                                    List<String> multi = props.get(k.getKey());
                                    if (multi == null) {
                                        multi = new ArrayList<String>();
                                        props.put(k.getKey(), multi);
                                    }
                                    multi.addAll(vals);
                                }
                            } else {
                                List<String> val = (List<String>) conf.getList(k.getKey());
                                if (val != null && !val.isEmpty()) {
                                    if (val.size() > 1) throw new RuntimeException(
                                                                                   "Illegal module plugin config entry found: "
                                                                                           + k.getKey()
                                                                                           + ", multi-values are not allowed for this key.");
                                    if (props.containsKey(k.getKey())) throw new RuntimeException(
                                                                                                  "Illegal module plugin config entry found: "
                                                                                                          + k.getKey()
                                                                                                          + ", multi-values are not allowed for this key.");
                                    props.put(k.getKey(), val);
                                }
                            }
                        }
                    } catch (ConfigurationException e) {
                        throw new RuntimeException("Illegal module plugin config file: " + url, e);
                    }
                }
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 从插件模块中找出所有的bean配置文件, 对应所有ocean-ext.properties文件中的'beans'属性配置
     */
    public static String[] resolveAllPluginBeanConfigFiles() {
        List<String> confs = props.get(PluginConf.beans.getKey());
        if (confs == null) return null;
        return confs.toArray(new String[confs.size()]);
    }

    /**
     * 取得插件指定的httpListener的beanId
     */
    public static String resolveHttpListenerName() {
        List<String> p = props.get(PluginConf.httpListener.getKey());
        return p == null ? null : p.get(0);
    }

    public static void main(String... args) {
        System.out.println(props);
    }

}