SPUtil-工具類 是專門對 Android共享首選項 SharedPreferences 的資料儲存/資料獲取，提供了公共的方法行為；

package common.library.utils;

import android.content.Context;
import android.content.SharedPreferences;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.math.BigDecimal;
 
import java.util.Map;

/**
 * @Author Liudeli
 * @Describe：
 */
public class SPUtil {

    /**
     * 儲存在手機裡面的檔名
     */
    // public static final String FILE_NAME = "share_data";


    /**
     * 儲存資料的方法，我們需要拿到儲存資料的具體型別，然後根據型別呼叫不同的儲存方法
     */
    /*public static void put(Context context, String key, Object object) {
        put(context, FILE_NAME, key, object);
    }
 
*/

    public static void put(Context context, String spFileName, String key, Object object) {
        SharedPreferences sp = context.getSharedPreferences(spFileName,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();

        if (object instanceof String) {
            editor.putString(key, (String) object);
        } 
 
else if (object instanceof Integer) {
            editor.putInt(key, (Integer) object);
        } else if (object instanceof Boolean) {
            editor.putBoolean(key, (Boolean) object);
        } else if (object instanceof Float) {
            editor.putFloat(key, (Float) object);
        } else if (object instanceof Long) {
            editor.putLong(key, (Long) object);
        } else {
            editor.putString(key, object.toString());
        }

        SharedPreferencesCompat.apply(editor);
    }

    public static void putString(Context context, String spFileName, String key, String stringData) {
        SharedPreferences sp = context.getSharedPreferences(spFileName,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();
        editor.putString(key, stringData);
        editor.commit();
        // SharedPreferencesCompat.apply(editor);
    }

    /**
     * 得到儲存資料的方法，我們根據預設值得到儲存的資料的具體型別，然後呼叫相對於的方法獲取值
     */
    /*public static Object get(Context context, String key, Object defaultObject) {
        return get(context, FILE_NAME, key, defaultObject);
    }*/

    public static Object get(Context context, String spName, String key, Object defaultObject) {
        SharedPreferences sp = context.getSharedPreferences(spName,
                Context.MODE_PRIVATE);

        if (defaultObject instanceof String) {
            return sp.getString(key, (String) defaultObject);
        } else if (defaultObject instanceof Integer) {
            return sp.getInt(key, (Integer) defaultObject);
        } else if (defaultObject instanceof Boolean) {
            return sp.getBoolean(key, (Boolean) defaultObject);
        } else if (defaultObject instanceof Float) {
            return sp.getFloat(key, (Float) defaultObject);
        } else if (defaultObject instanceof Long) {
            return sp.getLong(key, (Long) defaultObject);
        }

        return null;
    }

    public static String getString(Context context, String spName, String key, String stringDataDefault) {
        SharedPreferences sp = context.getSharedPreferences(spName,
                Context.MODE_PRIVATE);
        return sp.getString(key, stringDataDefault);
    }

    /**
     * 移除某個key值已經對應的值
     */
    /*public static void remove(Context context, String key) {
        remove(context, FILE_NAME, key);
    }*/

    public static void remove(Context context, String spFileName, String key) {
        SharedPreferences sp = context.getSharedPreferences(spFileName,
                Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();
        editor.remove(key);
        SharedPreferencesCompat.apply(editor);
    }

    /**
     * 清除所有資料
     */
    /*public static void clear(Context context) {
        clear(context, FILE_NAME);
    }*/

    public static void clear(Context context, String spFileName) {
        SharedPreferences sp = context.getSharedPreferences(spFileName, Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sp.edit();
        editor.clear();
        SharedPreferencesCompat.apply(editor);
    }

    /**
     * 查詢某個key是否已經存在
     */
    /*public static boolean contains(Context context, String key) {
        return contains(context, FILE_NAME, key);
    }*/

    public static boolean contains(Context context, String spFileName, String key) {
        SharedPreferences sp = context.getSharedPreferences(spFileName, Context.MODE_PRIVATE);
        return sp.contains(key);
    }

    /**
     * 返回所有的鍵值對
     */
    /*public static Map<String, ?> getAll(Context context) {
        return getAll(context, FILE_NAME);
    }*/

    public static Map<String, ?> getAll(Context context, String spName) {
        SharedPreferences sp = context.getSharedPreferences(spName,
                Context.MODE_PRIVATE);
        return sp.getAll();
    }

    /**
     * 建立一個解決SharedPreferencesCompat.apply方法的一個相容類
     */
    private static class SharedPreferencesCompat {
        private static final Method sApplyMethod = findApplyMethod();

        /**
         * 反射查詢apply的方法
         */
        @SuppressWarnings({"unchecked", "rawtypes"})
        private static Method findApplyMethod() {
            try {
                Class clz = SharedPreferences.Editor.class;
                return clz.getMethod("apply");
            } catch (NoSuchMethodException e) {
            }

            return null;
        }

        /**
         * 如果找到則使用apply執行，否則使用commit
         */
        public static void apply(SharedPreferences.Editor editor) {
            try {
                if (sApplyMethod != null) {
                    sApplyMethod.invoke(editor);
                    return;
                }
            } catch (IllegalArgumentException e) {
            } catch (IllegalAccessException e) {
            } catch (InvocationTargetException e) {
            }
            editor.commit();
        }
    }

    public static void main(String args[]) {

        // BigDecimal bigDecimal = 11111111112.46;

        BigDecimal b1 = new BigDecimal(Double.toString(11111111112.46));

        System.out.println(new BigDecimal(11111111112.46));
        System.out.println(new BigDecimal("11111111112.46"));

        System.out.println(b1.toString());
    }
}