android.os.SystemProperties反射帮助类

package com.viking;

import java.lang.reflect.Method;

import android.content.Context;

/**
* @author Viking.Den
*
* @email vikingden@live.com
*
* @time 2014-7-17
*/
public class SystemPropertiesProxy
{
/**
* This class cannot be instantiated
*/
private SystemPropertiesProxy(){

}

/**
* Get the value for the given key.
* @return an empty string if the key isn't found
* @throws IllegalArgumentException if the key exceeds 32 characters
*/
public static String get(Context context, String key) throws IllegalArgumentException {
String ret= "";
try{

ClassLoader cl = context.getClassLoader();
@SuppressWarnings("rawtypes")
Class SystemProperties = cl.loadClass("android.os.SystemProperties");

//Parameters Types
@SuppressWarnings("rawtypes")
Class[] paramTypes= new Class[1];
paramTypes[0]= String.class;

Method get = SystemProperties.getMethod("get", paramTypes);

//Parameters
Object[] params= new Object[1];
params[0]= new String(key);

ret= (String) get.invoke(SystemProperties, params);

}catch( IllegalArgumentException iAE ){
throw iAE;
}catch( Exception e ){
ret= "";
}

return ret;

}

/**
* Get the value for the given key.
* @return if the key isn't found, return def if it isn't null, or an empty string otherwise
* @throws IllegalArgumentException if the key exceeds 32 characters
*/
public static String get(Context context, String key, String def) throws IllegalArgumentException {
String ret= def;
try{

ClassLoader cl = context.getClassLoader();
@SuppressWarnings("rawtypes")
Class SystemProperties = cl.loadClass("android.os.SystemProperties");

//Parameters Types
@SuppressWarnings("rawtypes")
Class[] paramTypes= new Class[2];
paramTypes[0]= String.class;
paramTypes[1]= String.class;

Method get = SystemProperties.getMethod("get", paramTypes);

//Parameters
Object[] params= new Object[2];
params[0]= new String(key);
params[1]= new String(def);

ret= (String) get.invoke(SystemProperties, params);

}catch( IllegalArgumentException iAE ){
throw iAE;
}catch( Exception e ){
ret= def;
}

return ret;

}

/**
* Get the value for the given key, and return as an integer.
* @param key the key to lookup
* @param def a default value to return
* @return the key parsed as an integer, or def if the key isn't found or
*         cannot be parsed
* @throws IllegalArgumentException if the key exceeds 32 characters
*/
public static Integer getInt(Context context, String key, int def) throws IllegalArgumentException {
Integer ret= def;
try{

ClassLoader cl = context.getClassLoader();
@SuppressWarnings("rawtypes")
Class SystemProperties = cl.loadClass("android.os.SystemProperties");

//Parameters Types
@SuppressWarnings("rawtypes")
Class[] paramTypes= new Class[2];
paramTypes[0]= String.class;
paramTypes[1]= int.class;

Method getInt = SystemProperties.getMethod("getInt", paramTypes);

//Parameters
Object[] params= new Object[2];
params[0]= new String(key);
params[1]= new Integer(def);

ret= (Integer) getInt.invoke(SystemProperties, params);

}catch( IllegalArgumentException iAE ){
throw iAE;
}catch( Exception e ){
ret= def;
}

return ret;

}

/**
* Get the value for the given key, and return as a long.
* @param key the key to lookup
* @param def a default value to return
* @return the key parsed as a long, or def if the key isn't found or
*         cannot be parsed
* @throws IllegalArgumentException if the key exceeds 32 characters
*/
public static Long getLong(Context context, String key, long def) throws IllegalArgumentException {
Long ret= def;
try{

ClassLoader cl = context.getClassLoader();
@SuppressWarnings("rawtypes")
Class SystemProperties= cl.loadClass("android.os.SystemProperties");

//Parameters Types
@SuppressWarnings("rawtypes")
Class[] paramTypes= new Class[2];
paramTypes[0]= String.class;
paramTypes[1]= long.class;

Method getLong = SystemProperties.getMethod("getLong", paramTypes);

//Parameters
Object[] params= new Object[2];
params[0]= new String(key);
params[1]= new Long(def);

ret= (Long) getLong.invoke(SystemProperties, params);

}catch( IllegalArgumentException iAE ){
throw iAE;
}catch( Exception e ){
ret= def;
}

return ret;

}

/**
* Get the value for the given key, returned as a boolean.
* Values 'n', 'no', '0', 'false' or 'off' are considered false.
* Values 'y', 'yes', '1', 'true' or 'on' are considered true.
* (case insensitive).
* If the key does not exist, or has any other value, then the default
* result is returned.
* @param key the key to lookup
* @param def a default value to return
* @return the key parsed as a boolean, or def if the key isn't found or is
*         not able to be parsed as a boolean.
* @throws IllegalArgumentException if the key exceeds 32 characters
*/
public static Boolean getBoolean(Context context, String key, boolean def) throws IllegalArgumentException {
Boolean ret= def;
try{

ClassLoader cl = context.getClassLoader();
@SuppressWarnings("rawtypes")
Class SystemProperties = cl.loadClass("android.os.SystemProperties");

//Parameters Types
@SuppressWarnings("rawtypes")
Class[] paramTypes= new Class[2];
paramTypes[0]= String.class;
paramTypes[1]= boolean.class;

Method getBoolean = SystemProperties.getMethod("getBoolean", paramTypes);

//Parameters
Object[] params= new Object[2];
params[0]= new String(key);
params[1]= new Boolean(def);

ret= (Boolean) getBoolean.invoke(SystemProperties, params);

}catch( IllegalArgumentException iAE ){
throw iAE;
}catch( Exception e ){
ret= def;
}

return ret;

}

/**
* Set the value for the given key.
* @throws IllegalArgumentException if the key exceeds 32 characters
* @throws IllegalArgumentException if the value exceeds 92 characters
*/
public static void set(Context context, String key, String val) throws IllegalArgumentException {
try{

@SuppressWarnings("rawtypes")
Class SystemProperties = Class.forName("android.os.SystemProperties");

//Parameters Types
@SuppressWarnings("rawtypes")
Class[] paramTypes= new Class[2];
paramTypes[0]= String.class;
paramTypes[1]= String.class;

Method set = SystemProperties.getMethod("set", paramTypes);

//Parameters
Object[] params= new Object[2];
params[0]= new String(key);
params[1]= new String(val);

set.invoke(SystemProperties, params);

}catch( IllegalArgumentException iAE ){
throw iAE;
}catch( Exception e ){}
}
}