解析${}.doc

package redolvePlaceHolder;import java.io.IOException;import java.io.InputStream;import java.util.Iterator;import java.util.Map;import java.util.Properties;import java.util.Map.Entry;/* * 此类借用了hibernate读取properties文件的代码， * 可以解析占位符比如$ * author afei * */public class TestMain private static final String PLACEHOLDER_START = $;private static Properties pro;public static void main(String args) try pro=buildProperty(perties);resolvePlaceHolders(pro);printProperties(pro); catch (IOException e) e.printStackTrace();public static void printProperties(Properties p)Iterator it=p.entrySet().iterator();while(it.hasNext()Entry ent=(Entry)it.next();System.out.println(ent.getKey()+ : +ent.getValue();/* * 解析占位符 * param properties */public static void resolvePlaceHolders(Properties properties) Iterator itr = properties.entrySet().iterator();while ( itr.hasNext() ) final Map.Entry entry = ( Map.Entry ) itr.next();final Object value = entry.getValue();if ( value != null & String.class.isInstance( value ) ) final String resolved = resolvePlaceHolder( ( String ) value );if ( !value.equals( resolved ) ) if ( resolved = null ) itr.remove();else entry.setValue( resolved );/* * 解析占位符具体操作 * param property * return */public static String resolvePlaceHolder(String property) if ( property.indexOf( PLACEHOLDER_START ) 0 ) return property;StringBuffer buff = new StringBuffer();char chars = property.toCharArray();for ( int pos = 0; pos chars.length; pos+ ) if ( charspos = $ ) / peek aheadif ( charspos+1 = ) / we have a placeholder, spin forward till we find the endString systemPropertyName = ;int x = pos + 2;for ( ; x = chars.length ) break;buff.append( charspos );String rtn = buff.toString();return isEmpty( rtn ) ? null : rtn;/* * 构造properties文件 * param path * throws IOException */public static Properties buildProperty(String path) throws IOExceptionInputStream is=getResourceAsStream(perties);pro=new Properties();pro.load(is);return pro;/* * 构造properties文件的流 * param resource * return */public static InputStream getResourceAsStream(String resource) String stripped = resource.startsWith(/) ?resource.substring(1) : resource;InputStream stream = null;ClassLoader classLoader = Thread.currentThread().getContextClassLoader();if (classLoader!=null) stream = classLoader.getResourceAsStream( stripped );if ( stream = null ) stream = TestMain.class.getResourceAsStream( resource );if ( stream = null ) stream = TestMain.class.getClassLoader().getResourceAsStream( stripped );if ( stream = null ) throw new RuntimeException( resource + not found );return stream;/* * 获得系统属性 当然 你可以选择从别的地方获取值 * param systemPropertyName * return */private static String extractFromSystem(String systemPropertyName) try return System.getProperty( systemPropertyName );catch( Throwable t ) return nul