java:java.util.Properties的便利性封装

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java.util.Properties是个常用的类，主要用于保存参数，从文件中加载配置参数，为了更方便使用，可以对它做进一步的封装。
下是面封装后的类Configuration,增加了以下方法：
getProperty<primitive>(String)系列方法
getProperty<primitive>(String key, <primitive> defaultValue)系列方法
setProperty<primitive>(String key, <primitive>value)系列方法。
用于自动转换基本类型的参数值。
增加了以下不同参数的构造函数更方便参数文件加载

Configuration(ClassLoader classLoader,String propFile)Configuration(File propFile)Configuration(URL url)

另外增加了setPrefix(String prefix)方法可以用于相同前缀的参数的读取。

/**    * @Title: Configuratoin.java  * @Package net.gdface.utils  * @Description: 管理properties文件 * @author guyadong    * @date 2014-10-14 下午3:20:09  * @version V1.0    */package net.gdface.utils;import java.io.File;import java.io.IOException;import java.io.InputStream;import java.lang.reflect.InvocationTargetException;import java.net.URL;import java.util.Properties;/**读取配置文件(properties)中的参数 * @author guyadong *  */public class Configuration extends Properties{    private static final long serialVersionUID = -3929851625670931787L;    /**     * property 属性名前缀,在调用{@link #getProperty(String)}或其他getProperty方法时参数会自动加上该前缀,默认为"",     * 如prefix为 net.gdface.facedbsdk.FaceDbSDKLocal     * 调用getProperty("minThread")时，其实是执行getProperty("net.gdface.facedbsdk.FaceDbSDKLocal.minThread")     */    private ThreadLocal<String> prefixs = new ThreadLocal<String>() {        @Override        protected String initialValue() {            return "";//prefix初始值为""        }    };    /**使用指定的ClassLoader加载properties文件propFile     * @param classLoader     * @param propFile     * @throws IOException     * @see #configure(URL)     */    public Configuration(ClassLoader classLoader,String propFile) throws IOException {        URL url= classLoader.getResource(propFile);        if(null==url)            throw new IOException(String.format("Cant found resource [%s] by %s",propFile,classLoader.getClass().getName()));        configure(url);    }    /**     * 从{@link File}构造对象     * @param propFile     * @throws IOException     */    public Configuration(File propFile) throws IOException {        this(propFile.toURI().toURL());    }       public Configuration() {        super();    }    public Configuration(Properties defaults) {        super(defaults);    }    /**     * @param url     * @throws IOException     */    public Configuration(URL url) throws IOException {        configure(url);    }       /**     * 根据{@link URL}加载配置文件     * @param url     * @throws IOException     * @see #configure(InputStream)     */    private void configure(URL url) throws IOException {        if(null==url)            throw new NullPointerException("parameter [url] is null");        System.out.printf("Load properties from [%s]\n", url.toString());        InputStream is = url.openStream();        try {            load(is);        } finally {            is.close();        }    }    /**     * 读取指定的key，用静态valueOf方法(如果有)将之转换成clazz指定的类型<br>     * 适用于{@link Number}，{@link Boolean}类型,如果key不存在或为空或转换出错则返回null     *      * @param key     * @param clazz     * @return     */    @SuppressWarnings("unchecked")    private <T> T _getPropertyBaseType(String key, Class<T> clazz) {        if (null == key||0==key.length())            throw new IllegalArgumentException("the argument 'key' must not be null or empty");        if (null == clazz)            throw new IllegalArgumentException("the argument 'clazz' must not be null");        String value = getProperty(key);        try {            return null == value|| 0 == value.length() ? null : (T) clazz.getMethod("valueOf", String.class).invoke(null, value.trim());        } catch (NoSuchMethodException e) {            new RuntimeException(                    String.format("%s:not found static method 'valueOf' for %s", e.getClass().getSimpleName(),                            clazz.getName()), e);        } catch (IllegalAccessException e) {            new RuntimeException(                    String.format("%s:can't invoke method 'valueOf' for %s", e.getClass().getSimpleName(),                            clazz.getName()), e);        } catch (InvocationTargetException e) {            try {                throw e.getCause();            } catch (NumberFormatException ie) {                System.out.printf("%s: [%s=%s] can't be convert to %s\n", e.getClass().getSimpleName(), key, value,                        clazz.getName());            } catch (Throwable ie) {                new RuntimeException(ie);            }        }        return null;    }    /**     * 设置指定的key为value     *      * @param key     *            为{@link null}时抛出 {@link IllegalArgumentException}<br>     *            适用于{@link Number}，{@link Boolean}类型     * @param value     *            为{@code null}时删除key并返回{@code null}     * @return 用静态valueOf方法返回key原来的值     */    @SuppressWarnings("unchecked")    private <T> T _setPropertyBaseType(String key, T value) {               if (null == key||0==key.length())            throw new IllegalArgumentException("the argument 'key' must not be null or empty");        // value为null时删除key,并返回null        if(null==value){remove(key);return null;}        try {            String old = (String) setProperty(key,value.toString());            return null == old|| 0 == old.length() ? null : (T) value.getClass().getMethod("valueOf", String.class).invoke(null, old.trim());        } catch (NoSuchMethodException e) {            new RuntimeException(                    String.format("%s:not found static method 'valueOf' for %s", e.getClass().getSimpleName(),                            value.getClass().getName()), e);        } catch (IllegalAccessException e) {            new RuntimeException(                    String.format("%s:can't invoke method 'valueOf' for %s", e.getClass().getSimpleName(),                            value.getClass().getName()), e);        } catch (InvocationTargetException e) {            try {                throw e.getCause();            } catch (NumberFormatException ie) {                System.out.printf("%s: [%s=%s] can't be convert to %s\n", e.getClass().getSimpleName(), key, value.toString(),                        value.getClass().getName());            } catch (Throwable ie) {                new RuntimeException(ie);            }        }        return null;    }    @Override    public String getProperty(String key) {        return super.getProperty(this.getPrefix()+key);    }    @Override    public String getProperty(String key, String defaultValue) {        return super.getProperty(this.getPrefix()+key, defaultValue);    }    @Override    public synchronized Object setProperty(String key, String value) {        return super.setProperty(this.getPrefix()+key, value);    }    /**读取指定的key，将之转换成与defaultValue类型相同的对象，如果key不存在或转换出错则返回defaultValue     * @param key     * @param defaultValue 缺省值     * @return     */    public <T> T getPropertyBaseType(String key, T defaultValue) {        if (null == defaultValue)            throw new IllegalArgumentException("the argument 'defaultValue' must not be null");        @SuppressWarnings("unchecked")        T res = (T) _getPropertyBaseType(key,defaultValue.getClass());        return  ((null==res)?defaultValue:res);    }    public Boolean getPropertyBoolean(String key) {        return _getPropertyBaseType(key, Boolean.class);    }    public boolean getPropertyBoolean(String key, Boolean defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    public Byte getPropertyByte(String key) {        return _getPropertyBaseType(key, Byte.class);    }    public Byte getPropertyByte(String key,Byte defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    public Double getPropertyDouble(String key) {        return _getPropertyBaseType(key, Double.class);    }    public Double getPropertyDouble(String key,Double defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    public Float getPropertyFloat(String key) {        return _getPropertyBaseType(key, Float.class);    }    public Float getPropertyFloat(String key,Float defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    public Integer getPropertyInteger(String key) {        return _getPropertyBaseType(key, Integer.class);    }    public Integer getPropertyInteger(String key,Integer defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    public Long getPropertyLong(String key) {        return _getPropertyBaseType(key, Long.class);    }    public Long getPropertyLong(String key,Long defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    public Short getPropertyShort(String key) {        return _getPropertyBaseType(key, Short.class);    }    public Short getPropertyShort(String key,Short defaultValue) {        return getPropertyBaseType(key, defaultValue);    }    //////////////    public boolean setPropertyBoolean(String key, Boolean value) {        return _setPropertyBaseType(key, value);    }    public Byte setPropertyByte(String key,Byte value) {        return _setPropertyBaseType(key, value);    }    public Double setPropertyDouble(String key,Double value) {        return _setPropertyBaseType(key, value);    }    public Float setPropertyFloat(String key,Float value) {        return _setPropertyBaseType(key, value);    }    public Integer setPropertyInteger(String key,Integer value) {        return _setPropertyBaseType(key, value);    }    public Long setPropertyLong(String key,Long value) {        return _setPropertyBaseType(key, value);    }    public Short setPropertyShort(String key,Short value) {        return _setPropertyBaseType(key, value);    }       /**如果参数为null，则prefix设置为""     * @param prefix 要设置的 prefix     * @return      */    public Configuration setPrefix(String prefix) {        prefixs.set(null==prefix?"":prefix);        return this;    }    /**     * @return prefix     */    public String getPrefix() {        return prefixs.get();    }}

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