Android快速开发系列 10个常用工具类

打开大家手上的项目，基本都会有一大批的辅助类，今天特此整理出10个基本每个项目中都会使用的工具类，用于快速开发~~

在此感谢群里给我发项目中工具类的兄弟/姐妹~

1、日志工具类L.java

    package com.zhy.utils;  
      
    import android.util.Log;  
      
    /** 
     * Log统一管理类 
     *  
     *  
     *  
     */  
    public class L  
    {  
      
        private L()  
        {  
            /* cannot be instantiated */  
            throw new UnsupportedOperationException("cannot be instantiated");  
        }  
      
        public static boolean isDebug = true;// 是否需要打印bug，可以在application的onCreate函数里面初始化  
        private static final String TAG = "way";  
      
        // 下面四个是默认tag的函数  
        public static void i(String msg)  
        {  
            if (isDebug)  
                Log.i(TAG, msg);  
        }  
      
        public static void d(String msg)  
        {  
            if (isDebug)  
                Log.d(TAG, msg);  
        }  
      
        public static void e(String msg)  
        {  
            if (isDebug)  
                Log.e(TAG, msg);  
        }  
      
        public static void v(String msg)  
        {  
            if (isDebug)  
                Log.v(TAG, msg);  
        }  
      
        // 下面是传入自定义tag的函数  
        public static void i(String tag, String msg)  
        {  
            if (isDebug)  
                Log.i(tag, msg);  
        }  
      
        public static void d(String tag, String msg)  
        {  
            if (isDebug)  
                Log.i(tag, msg);  
        }  
      
        public static void e(String tag, String msg)  
        {  
            if (isDebug)  
                Log.i(tag, msg);  
        }  
      
        public static void v(String tag, String msg)  
        {  
            if (isDebug)  
                Log.i(tag, msg);  
        }  
    }  

网上看到的类，注释上应该原创作者的名字，很简单的一个类；网上也有很多提供把日志记录到SDCard上的，不过我是从来没记录过，所以引入个最简单的，大家可以进行评价是否需要扩充~~

2、Toast统一管理类

    package com.zhy.utils;  
      
    import android.content.Context;  
    import android.widget.Toast;  
      
    /** 
     * Toast统一管理类 
     *  
     */  
    public class T  
    {  
      
        private T()  
        {  
            /* cannot be instantiated */  
            throw new UnsupportedOperationException("cannot be instantiated");  
        }  
      
        public static boolean isShow = true;  
      
        /** 
         * 短时间显示Toast 
         *  
         * @param context 
         * @param message 
         */  
        public static void showShort(Context context, CharSequence message)  
        {  
            if (isShow)  
                Toast.makeText(context, message, Toast.LENGTH_SHORT).show();  
        }  
      
        /** 
         * 短时间显示Toast 
         *  
         * @param context 
         * @param message 
         */  
        public static void showShort(Context context, int message)  
        {  
            if (isShow)  
                Toast.makeText(context, message, Toast.LENGTH_SHORT).show();  
        }  
      
        /** 
         * 长时间显示Toast 
         *  
         * @param context 
         * @param message 
         */  
        public static void showLong(Context context, CharSequence message)  
        {  
            if (isShow)  
                Toast.makeText(context, message, Toast.LENGTH_LONG).show();  
        }  
      
        /** 
         * 长时间显示Toast 
         *  
         * @param context 
         * @param message 
         */  
        public static void showLong(Context context, int message)  
        {  
            if (isShow)  
                Toast.makeText(context, message, Toast.LENGTH_LONG).show();  
        }  
      
        /** 
         * 自定义显示Toast时间 
         *  
         * @param context 
         * @param message 
         * @param duration 
         */  
        public static void show(Context context, CharSequence message, int duration)  
        {  
            if (isShow)  
                Toast.makeText(context, message, duration).show();  
        }  
      
        /** 
         * 自定义显示Toast时间 
         *  
         * @param context 
         * @param message 
         * @param duration 
         */  
        public static void show(Context context, int message, int duration)  
        {  
            if (isShow)  
                Toast.makeText(context, message, duration).show();  
        }  
      
    }  

也是非常简单的一个封装，能省则省了~~

3、SharedPreferences封装类SPUtils

    package com.zhy.utils;  
      
    import java.lang.reflect.InvocationTargetException;  
    import java.lang.reflect.Method;  
    import java.util.Map;  
      
    import android.content.Context;  
    import android.content.SharedPreferences;  
      
    public class SPUtils  
    {  
        /** 
         * 保存在手机里面的文件名 
         */  
        public static final String FILE_NAME = "share_data";  
      
        /** 
         * 保存数据的方法，我们需要拿到保存数据的具体类型，然后根据类型调用不同的保存方法 
         *  
         * @param context 
         * @param key 
         * @param object 
         */  
        public static void put(Context context, String key, Object object)  
        {  
      
            SharedPreferences sp = context.getSharedPreferences(FILE_NAME,  
                    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);  
        }  
      
        /** 
         * 得到保存数据的方法，我们根据默认值得到保存的数据的具体类型，然后调用相对于的方法获取值 
         *  
         * @param context 
         * @param key 
         * @param defaultObject 
         * @return 
         */  
        public static Object get(Context context, String key, Object defaultObject)  
        {  
            SharedPreferences sp = context.getSharedPreferences(FILE_NAME,  
                    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;  
        }  
      
        /** 
         * 移除某个key值已经对应的值 
         * @param context 
         * @param key 
         */  
        public static void remove(Context context, String key)  
        {  
            SharedPreferences sp = context.getSharedPreferences(FILE_NAME,  
                    Context.MODE_PRIVATE);  
            SharedPreferences.Editor editor = sp.edit();  
            editor.remove(key);  
            SharedPreferencesCompat.apply(editor);  
        }  
      
        /** 
         * 清除所有数据 
         * @param context 
         */  
        public static void clear(Context context)  
        {  
            SharedPreferences sp = context.getSharedPreferences(FILE_NAME,  
                    Context.MODE_PRIVATE);  
            SharedPreferences.Editor editor = sp.edit();  
            editor.clear();  
            SharedPreferencesCompat.apply(editor);  
        }  
      
        /** 
         * 查询某个key是否已经存在 
         * @param context 
         * @param key 
         * @return 
         */  
        public static boolean contains(Context context, String key)  
        {  
            SharedPreferences sp = context.getSharedPreferences(FILE_NAME,  
                    Context.MODE_PRIVATE);  
            return sp.contains(key);  
        }  
      
        /** 
         * 返回所有的键值对 
         *  
         * @param context 
         * @return 
         */  
        public static Map<String, ?> getAll(Context context)  
        {  
            SharedPreferences sp = context.getSharedPreferences(FILE_NAME,  
                    Context.MODE_PRIVATE);  
            return sp.getAll();  
        }  
      
        /** 
         * 创建一个解决SharedPreferencesCompat.apply方法的一个兼容类 
         *  
         * @author zhy 
         *  
         */  
        private static class SharedPreferencesCompat  
        {  
            private static final Method sApplyMethod = findApplyMethod();  
      
            /** 
             * 反射查找apply的方法 
             *  
             * @return 
             */  
            @SuppressWarnings({ "unchecked", "rawtypes" })  
            private static Method findApplyMethod()  
            {  
                try  
                {  
                    Class clz = SharedPreferences.Editor.class;  
                    return clz.getMethod("apply");  
                } catch (NoSuchMethodException e)  
                {  
                }  
      
                return null;  
            }  
      
            /** 
             * 如果找到则使用apply执行，否则使用commit 
             *  
             * @param editor 
             */  
            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();  
            }  
        }  
      
    }  

对SharedPreference的使用做了建议的封装，对外公布出put，get，remove，clear等等方法；

注意一点，里面所有的commit操作使用了SharedPreferencesCompat.apply进行了替代，目的是尽可能的使用apply代替commit

首先说下为什么，因为commit方法是同步的，并且我们很多时候的commit操作都是UI线程中，毕竟是IO操作，尽可能异步；

所以我们使用apply进行替代，apply异步的进行写入；

但是apply相当于commit来说是new API呢，为了更好的兼容，我们做了适配；

SharedPreferencesCompat也可以给大家创建兼容类提供了一定的参考~~

4、单位转换类 DensityUtils

/** 
 * 常用单位转换的辅助类 
 *  
 *  
 *  
 */  
public class DensityUtils  
{  
    private DensityUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
    }  
  
    /** 
     * dp转px 
     *  
     * @param context 
     * @param val 
     * @return 
     */  
    public static int dp2px(Context context, float dpVal)  
    {  
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,  
                dpVal, context.getResources().getDisplayMetrics());  
    }  
  
    /** 
     * sp转px 
     *  
     * @param context 
     * @param val 
     * @return 
     */  
    public static int sp2px(Context context, float spVal)  
    {  
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,  
                spVal, context.getResources().getDisplayMetrics());  
    }  
  
    /** 
     * px转dp 
     *  
     * @param context 
     * @param pxVal 
     * @return 
     */  
    public static float px2dp(Context context, float pxVal)  
    {  
        final float scale = context.getResources().getDisplayMetrics().density;  
        return (pxVal / scale);  
    }  
  
    /** 
     * px转sp 
     *  
     * @param fontScale 
     * @param pxVal 
     * @return 
     */  
    public static float px2sp(Context context, float pxVal)  
    {  
        return (pxVal / context.getResources().getDisplayMetrics().scaledDensity);  
    }  
  
}  

5、SD卡相关辅助类 SDCardUtils

/** 
 * SD卡相关的辅助类 
 *  
 *  
 *  
 */  
public class SDCardUtils  
{  
    private SDCardUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
    }  
  
    /** 
     * 判断SDCard是否可用 
     *  
     * @return 
     */  
    public static boolean isSDCardEnable()  
    {  
        return Environment.getExternalStorageState().equals(  
                Environment.MEDIA_MOUNTED);  
  
    }  
  
    /** 
     * 获取SD卡路径 
     *  
     * @return 
     */  
    public static String getSDCardPath()  
    {  
        return Environment.getExternalStorageDirectory().getAbsolutePath()  
                + File.separator;  
    }  
  
    /** 
     * 获取SD卡的剩余容量 单位byte 
     *  
     * @return 
     */  
    public static long getSDCardAllSize()  
    {  
        if (isSDCardEnable())  
        {  
            StatFs stat = new StatFs(getSDCardPath());  
            // 获取空闲的数据块的数量  
            long availableBlocks = (long) stat.getAvailableBlocks() - 4;  
            // 获取单个数据块的大小（byte）  
            long freeBlocks = stat.getAvailableBlocks();  
            return freeBlocks * availableBlocks;  
        }  
        return 0;  
    }  
  
    /** 
     * 获取指定路径所在空间的剩余可用容量字节数，单位byte 
     *  
     * @param filePath 
     * @return 容量字节 SDCard可用空间，内部存储可用空间 
     */  
    public static long getFreeBytes(String filePath)  
    {  
        // 如果是sd卡的下的路径，则获取sd卡可用容量  
        if (filePath.startsWith(getSDCardPath()))  
        {  
            filePath = getSDCardPath();  
        } else  
        {// 如果是内部存储的路径，则获取内存存储的可用容量  
            filePath = Environment.getDataDirectory().getAbsolutePath();  
        }  
        StatFs stat = new StatFs(filePath);  
        long availableBlocks = (long) stat.getAvailableBlocks() - 4;  
        return stat.getBlockSize() * availableBlocks;  
    }  
  
    /** 
     * 获取系统存储路径 
     *  
     * @return 
     */  
    public static String getRootDirectoryPath()  
    {  
        return Environment.getRootDirectory().getAbsolutePath();  
    }  
  
  
}  

6、屏幕相关辅助类 ScreenUtils

/** 
 * 获得屏幕相关的辅助类 
 *  
 *  
 *  
 */  
public class ScreenUtils  
{  
    private ScreenUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
    }  
  
    /** 
     * 获得屏幕高度 
     *  
     * @param context 
     * @return 
     */  
    public static int getScreenWidth(Context context)  
    {  
        WindowManager wm = (WindowManager) context  
                .getSystemService(Context.WINDOW_SERVICE);  
        DisplayMetrics outMetrics = new DisplayMetrics();  
        wm.getDefaultDisplay().getMetrics(outMetrics);  
        return outMetrics.widthPixels;  
    }  
  
    /** 
     * 获得屏幕宽度 
     *  
     * @param context 
     * @return 
     */  
    public static int getScreenHeight(Context context)  
    {  
        WindowManager wm = (WindowManager) context  
                .getSystemService(Context.WINDOW_SERVICE);  
        DisplayMetrics outMetrics = new DisplayMetrics();  
        wm.getDefaultDisplay().getMetrics(outMetrics);  
        return outMetrics.heightPixels;  
    }  
  
    /** 
     * 获得状态栏的高度 
     *  
     * @param context 
     * @return 
     */  
    public static int getStatusHeight(Context context)  
    {  
  
        int statusHeight = -1;  
        try  
        {  
            Class<?> clazz = Class.forName("com.android.internal.R$dimen");  
            Object object = clazz.newInstance();  
            int height = Integer.parseInt(clazz.getField("status_bar_height")  
                    .get(object).toString());  
            statusHeight = context.getResources().getDimensionPixelSize(height);  
        } catch (Exception e)  
        {  
            e.printStackTrace();  
        }  
        return statusHeight;  
    }  
  
    /** 
     * 获取当前屏幕截图，包含状态栏 
     *  
     * @param activity 
     * @return 
     */  
    public static Bitmap snapShotWithStatusBar(Activity activity)  
    {  
        View view = activity.getWindow().getDecorView();  
        view.setDrawingCacheEnabled(true);  
        view.buildDrawingCache();  
        Bitmap bmp = view.getDrawingCache();  
        int width = getScreenWidth(activity);  
        int height = getScreenHeight(activity);  
        Bitmap bp = null;  
        bp = Bitmap.createBitmap(bmp, 0, 0, width, height);  
        view.destroyDrawingCache();  
        return bp;  
  
    }  
  
    /** 
     * 获取当前屏幕截图，不包含状态栏 
     *  
     * @param activity 
     * @return 
     */  
    public static Bitmap snapShotWithoutStatusBar(Activity activity)  
    {  
        View view = activity.getWindow().getDecorView();  
        view.setDrawingCacheEnabled(true);  
        view.buildDrawingCache();  
        Bitmap bmp = view.getDrawingCache();  
        Rect frame = new Rect();  
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);  
        int statusBarHeight = frame.top;  
  
        int width = getScreenWidth(activity);  
        int height = getScreenHeight(activity);  
        Bitmap bp = null;  
        bp = Bitmap.createBitmap(bmp, 0, statusBarHeight, width, height  
                - statusBarHeight);  
        view.destroyDrawingCache();  
        return bp;  
  
    }  
  
}  

7、App相关辅助类

/** 
 * 跟App相关的辅助类 
 *  
 *  
 *  
 */  
public class AppUtils  
{  
  
    private AppUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
  
    }  
  
    /** 
     * 获取应用程序名称 
     */  
    public static String getAppName(Context context)  
    {  
        try  
        {  
            PackageManager packageManager = context.getPackageManager();  
            PackageInfo packageInfo = packageManager.getPackageInfo(  
                    context.getPackageName(), 0);  
            int labelRes = packageInfo.applicationInfo.labelRes;  
            return context.getResources().getString(labelRes);  
        } catch (NameNotFoundException e)  
        {  
            e.printStackTrace();  
        }  
        return null;  
    }  
  
    /** 
     * [获取应用程序版本名称信息] 
     *  
     * @param context 
     * @return 当前应用的版本名称 
     */  
    public static String getVersionName(Context context)  
    {  
        try  
        {  
            PackageManager packageManager = context.getPackageManager();  
            PackageInfo packageInfo = packageManager.getPackageInfo(  
                    context.getPackageName(), 0);  
            return packageInfo.versionName;  
  
        } catch (NameNotFoundException e)  
        {  
            e.printStackTrace();  
        }  
        return null;  
    }  
  
}  

8、软键盘相关辅助类KeyBoardUtils

/** 
 * 打开或关闭软键盘 
 *  
 * @author zhy 
 *  
 */  
public class KeyBoardUtils  
{  
    /** 
     * 打卡软键盘 
     *  
     * @param mEditText 
     *            输入框 
     * @param mContext 
     *            上下文 
     */  
    public static void openKeybord(EditText mEditText, Context mContext)  
    {  
        InputMethodManager imm = (InputMethodManager) mContext  
                .getSystemService(Context.INPUT_METHOD_SERVICE);  
        imm.showSoftInput(mEditText, InputMethodManager.RESULT_SHOWN);  
        imm.toggleSoftInput(InputMethodManager.SHOW_FORCED,  
                InputMethodManager.HIDE_IMPLICIT_ONLY);  
    }  
  
    /** 
     * 关闭软键盘 
     *  
     * @param mEditText 
     *            输入框 
     * @param mContext 
     *            上下文 
     */  
    public static void closeKeybord(EditText mEditText, Context mContext)  
    {  
        InputMethodManager imm = (InputMethodManager) mContext  
                .getSystemService(Context.INPUT_METHOD_SERVICE);  
  
        imm.hideSoftInputFromWindow(mEditText.getWindowToken(), 0);  
    }  
}  

9、网络相关辅助类 NetUtils

/** 
 * 跟网络相关的工具类 
 *  
 *  
 *  
 */  
public class NetUtils  
{  
    private NetUtils()  
    {  
        /* cannot be instantiated */  
        throw new UnsupportedOperationException("cannot be instantiated");  
    }  
  
    /** 
     * 判断网络是否连接 
     *  
     * @param context 
     * @return 
     */  
    public static boolean isConnected(Context context)  
    {  
  
        ConnectivityManager connectivity = (ConnectivityManager) context  
                .getSystemService(Context.CONNECTIVITY_SERVICE);  
  
        if (null != connectivity)  
        {  
  
            NetworkInfo info = connectivity.getActiveNetworkInfo();  
            if (null != info && info.isConnected())  
            {  
                if (info.getState() == NetworkInfo.State.CONNECTED)  
                {  
                    return true;  
                }  
            }  
        }  
        return false;  
    }  
  
    /** 
     * 判断是否是wifi连接 
     */  
    public static boolean isWifi(Context context)  
    {  
        ConnectivityManager cm = (ConnectivityManager) context  
                .getSystemService(Context.CONNECTIVITY_SERVICE);  
  
        if (cm == null)  
            return false;  
        return cm.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI;  
  
    }  
  
    /** 
     * 打开网络设置界面 
     */  
    public static void openSetting(Activity activity)  
    {  
        Intent intent = new Intent("/");  
        ComponentName cm = new ComponentName("com.android.settings",  
                "com.android.settings.WirelessSettings");  
        intent.setComponent(cm);  
        intent.setAction("android.intent.action.VIEW");  
        activity.startActivityForResult(intent, 0);  
    }  
  
}  

10、Http相关辅助类 HttpUtils

/** 
 * Http请求的工具类 
 *  
 * @author zhy 
 *  
 */  
public class HttpUtils  
{  
  
    private static final int TIMEOUT_IN_MILLIONS = 5000;  
  
    public interface CallBack  
    {  
        void onRequestComplete(String result);  
    }  
  
  
    /** 
     * 异步的Get请求 
     *  
     * @param urlStr 
     * @param callBack 
     */  
    public static void doGetAsyn(final String urlStr, final CallBack callBack)  
    {  
        new Thread()  
        {  
            public void run()  
            {  
                try  
                {  
                    String result = doGet(urlStr);  
                    if (callBack != null)  
                    {  
                        callBack.onRequestComplete(result);  
                    }  
                } catch (Exception e)  
                {  
                    e.printStackTrace();  
                }  
  
            };  
        }.start();  
    }  
  
    /** 
     * 异步的Post请求 
     * @param urlStr 
     * @param params 
     * @param callBack 
     * @throws Exception 
     */  
    public static void doPostAsyn(final String urlStr, final String params,  
            final CallBack callBack) throws Exception  
    {  
        new Thread()  
        {  
            public void run()  
            {  
                try  
                {  
                    String result = doPost(urlStr, params);  
                    if (callBack != null)  
                    {  
                        callBack.onRequestComplete(result);  
                    }  
                } catch (Exception e)  
                {  
                    e.printStackTrace();  
                }  
  
            };  
        }.start();  
  
    }  
  
    /** 
     * Get请求，获得返回数据 
     *  
     * @param urlStr 
     * @return 
     * @throws Exception 
     */  
    public static String doGet(String urlStr)   
    {  
        URL url = null;  
        HttpURLConnection conn = null;  
        InputStream is = null;  
        ByteArrayOutputStream baos = null;  
        try  
        {  
            url = new URL(urlStr);  
            conn = (HttpURLConnection) url.openConnection();  
            conn.setReadTimeout(TIMEOUT_IN_MILLIONS);  
            conn.setConnectTimeout(TIMEOUT_IN_MILLIONS);  
            conn.setRequestMethod("GET");  
            conn.setRequestProperty("accept", "*/*");  
            conn.setRequestProperty("connection", "Keep-Alive");  
            if (conn.getResponseCode() == 200)  
            {  
                is = conn.getInputStream();  
                baos = new ByteArrayOutputStream();  
                int len = -1;  
                byte[] buf = new byte[128];  
  
                while ((len = is.read(buf)) != -1)  
                {  
                    baos.write(buf, 0, len);  
                }  
                baos.flush();  
                return baos.toString();  
            } else  
            {  
                throw new RuntimeException(" responseCode is not 200 ... ");  
            }  
  
        } catch (Exception e)  
        {  
            e.printStackTrace();  
        } finally  
        {  
            try  
            {  
                if (is != null)  
                    is.close();  
            } catch (IOException e)  
            {  
            }  
            try  
            {  
                if (baos != null)  
                    baos.close();  
            } catch (IOException e)  
            {  
            }  
            conn.disconnect();  
        }  
          
        return null ;  
  
    }  
  
    /**  
     * 向指定 URL 发送POST方法的请求  
     *   
     * @param url  
     *            发送请求的 URL  
     * @param param  
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。  
     * @return 所代表远程资源的响应结果  
     * @throws Exception  
     */  
    public static String doPost(String url, String param)   
    {  
        PrintWriter out = null;  
        BufferedReader in = null;  
        String result = "";  
        try  
        {  
            URL realUrl = new URL(url);  
            // 打开和URL之间的连接  
            HttpURLConnection conn = (HttpURLConnection) realUrl  
                    .openConnection();  
            // 设置通用的请求属性  
            conn.setRequestProperty("accept", "*/*");  
            conn.setRequestProperty("connection", "Keep-Alive");  
            conn.setRequestMethod("POST");  
            conn.setRequestProperty("Content-Type",  
                    "application/x-www-form-urlencoded");  
            conn.setRequestProperty("charset", "utf-8");  
            conn.setUseCaches(false);  
            // 发送POST请求必须设置如下两行  
            conn.setDoOutput(true);  
            conn.setDoInput(true);  
            conn.setReadTimeout(TIMEOUT_IN_MILLIONS);  
            conn.setConnectTimeout(TIMEOUT_IN_MILLIONS);  
  
            if (param != null && !param.trim().equals(""))  
            {  
                // 获取URLConnection对象对应的输出流  
                out = new PrintWriter(conn.getOutputStream());  
                // 发送请求参数  
                out.print(param);  
                // flush输出流的缓冲  
                out.flush();  
            }  
            // 定义BufferedReader输入流来读取URL的响应  
            in = new BufferedReader(  
                    new InputStreamReader(conn.getInputStream()));  
            String line;  
            while ((line = in.readLine()) != null)  
            {  
                result += line;  
            }  
        } catch (Exception e)  
        {  
            e.printStackTrace();  
        }  
        // 使用finally块来关闭输出流、输入流  
        finally  
        {  
            try  
            {  
                if (out != null)  
                {  
                    out.close();  
                }  
                if (in != null)  
                {  
                    in.close();  
                }  
            } catch (IOException ex)  
            {  
                ex.printStackTrace();  
            }  
        }  
        return result;  
    }  
}  

如果大家在使用过程中出现什么错误，或者有更好的建议，欢迎大家留言提出~~可以不断的改进这些类~

原文地址：http://blog.csdn.net/lmj623565791/article/details/38965311，

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