Source Code Cross Referenced for PlaceholderUtils.java in  » J2EE » jfox » org » jfox » util » Java Source Code / Java DocumentationJava Source Code and Java Documentation

001:        /*
002:         * JFox - The most lightweight Java EE Application Server!
003:         * more details please visit http://www.huihoo.org/jfox or http://www.jfox.org.cn.
004:         *
005:         * JFox is licenced and re-distributable under GNU LGPL.
006:         */
007:        package org.jfox.util;
008:
009:        import java.io.FileNotFoundException;
010:        import java.io.IOException;
011:        import java.io.InputStream;
012:        import java.net.URL;
013:        import java.util.ArrayList;
014:        import java.util.List;
015:        import java.util.Map;
016:        import java.util.Properties;
017:
018:        import org.apache.log4j.Logger;
019:
020:        /**
021:         * ��符替�工具类
022:         *
023:         * @author <a href="mailto:jfox.young@gmail.com">Young Yang</a>
024:         */
025:        public class PlaceholderUtils {
026:
027:            private static final Logger logger = Logger
028:                    .getLogger(PlaceholderUtils.class);
029:
030:            /**
031:             * 全局属性
032:             */
033:            private Properties globalProperties = new Properties();
034:
035:            private static List<String> loadedProperties = new ArrayList<String>();
036:
037:            private static final PlaceholderUtils instance = new PlaceholderUtils();
038:
039:            private PlaceholderUtils() {
040:            }
041:
042:            private void loadProperties(Properties prop) {
043:                globalProperties.putAll(prop);
044:            }
045:
046:            public static PlaceholderUtils getInstance() {
047:                return instance;
048:            }
049:
050:            /**
051:             * 装载一个全局�置文件
052:             *
053:             * @param filename properties file name
054:             * @return PlaceHolderUtil
055:             * @throws IOException if failed to load property file
056:             */
057:            public static PlaceholderUtils loadGlobalProperty(String filename)
058:                    throws IOException {
059:                if (!loadedProperties.contains(filename)) {
060:                    InputStream in = PlaceholderUtils.class.getClassLoader()
061:                            .getResourceAsStream(filename);
062:                    if (in != null) {
063:                        Properties prop = new Properties();
064:                        prop.load(in);
065:                        in.close();
066:                        instance.loadProperties(prop);
067:                        loadedProperties.add(filename);
068:                    } else {
069:                        throw new FileNotFoundException(filename);
070:                    }
071:                }
072:                return instance;
073:            }
074:
075:            /**
076:             * 替� placeholder
077:             *
078:             * @param template 输入的模版
079:             * @return 替�之�的内容
080:             */
081:            public String evaluate(String template) {
082:                return VelocityUtils.evaluate(template, (Map) globalProperties);
083:            }
084:
085:            /**
086:             * 从一个文件中替�，返回替��的文本
087:             *
088:             * @param url file url
089:             * @return 替��的文本
090:             * @throws IOException if failed to load file
091:             */
092:            public String evaluate(URL url) throws IOException {
093:                InputStream in = url.openStream();
094:                if (in != null) {
095:                    String content = IOUtils.toString(in);
096:                    in.close();
097:                    return evaluate(content);
098:                } else {
099:                    return "";
100:                }
101:            }
102:
103:            public static void main(String[] args) throws Exception {
104:                PlaceholderUtils pu = loadGlobalProperty("global.properties");
105:                System.out.println(pu
106:                        .evaluate("I use database type is ${db_type}!"));
107:
108:            }
109:        }