Java占位符替换工具类详解编程语言

    import java.util.HashMap;   
    import java.util.Map;   
       
    import org.slf4j.Logger;   
    import org.slf4j.LoggerFactory;   
       
    /**  
     * 配置文件或模板中的占位符替换工具类  
     * Date: 15-5-8  
     * Time: 下午4:12  
     */   
    public class PlaceholderUtils {   
       
        private static final Logger logger = LoggerFactory.getLogger(PlaceholderUtils.class);   
       
        /**  
         * Prefix for system property placeholders: "${"  
         */   
        public static final String PLACEHOLDER_PREFIX = "${";   
        /**  
         * Suffix for system property placeholders: "}"  
         */   
        public static final String PLACEHOLDER_SUFFIX = "}";   
       
        public static String resolvePlaceholders(String text, Map<String, String> parameter) {   
            if (parameter == null || parameter.isEmpty()) {   
                return text;   
            }   
            StringBuffer buf = new StringBuffer(text);   
            int startIndex = buf.indexOf(PLACEHOLDER_PREFIX);   
            while (startIndex != -1) {   
                int endIndex = buf.indexOf(PLACEHOLDER_SUFFIX, startIndex + PLACEHOLDER_PREFIX.length());   
                if (endIndex != -1) {   
                    String placeholder = buf.substring(startIndex + PLACEHOLDER_PREFIX.length(), endIndex);   
                    int nextIndex = endIndex + PLACEHOLDER_SUFFIX.length();   
                    try {   
                        String propVal = parameter.get(placeholder);   
                        if (propVal != null) {   
                            buf.replace(startIndex, endIndex + PLACEHOLDER_SUFFIX.length(), propVal);   
                            nextIndex = startIndex + propVal.length();   
                        } else {   
                            logger.warn("Could not resolve placeholder '" + placeholder + "' in [" + text + "] ");   
                        }   
                    } catch (Exception ex) {   
                        logger.warn("Could not resolve placeholder '" + placeholder + "' in [" + text + "]: " + ex);   
                    }   
                    startIndex = buf.indexOf(PLACEHOLDER_PREFIX, nextIndex);   
                } else {   
                    startIndex = -1;   
                }   
            }   
            return buf.toString();   
        }   
           
        public static void main(String[] args) {   
            String aa= "我们都是好孩子,${num}说是嘛？ 我觉得${people}是傻蛋!";   
            Map<String, String> map = new HashMap<String, String>();   
            map.put("num","小二比");   
            map.put("people","小明");   
            System.out.println(PlaceholderUtils.resolvePlaceholders(aa, map));   
        }   
       
    }