Android开发 10个常用工具类

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原文出处: 张鸿洋的博客  

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

    package com.zhy.utils;  

    import android.content.Context;  
    import android.util.TypedValue;  

    /** 
     * 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

package com.zhy.utils;  

import java.io.File;  

import android.os.Environment;  
import android.os.StatFs;  

/** 
 * 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

    package com.zhy.utils;  

    import android.app.Activity;  
    import android.content.Context;  
    import android.graphics.Bitmap;  
    import android.graphics.Rect;  
    import android.util.DisplayMetrics;  
    import android.view.View;  
    import android.view.WindowManager;  

    /** 
     * 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

    package com.zhy.utils;  

    import android.content.Context;  
    import android.content.pm.PackageInfo;  
    import android.content.pm.PackageManager;  
    import android.content.pm.PackageManager.NameNotFoundException;  

    /** 
     * 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

    package com.zhy.utils;  

    import android.content.Context;  
    import android.view.inputmethod.InputMethodManager;  
    import android.widget.EditText;  

    /** 
     * 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

    package com.zhy.utils;  

    import android.app.Activity;  
    import android.content.ComponentName;  
    import android.content.Context;  
    import android.content.Intent;  
    import android.net.ConnectivityManager;  
    import android.net.NetworkInfo;  

    /** 
     * 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

    package com.zhy.utils;  

    import java.io.BufferedReader;  
    import java.io.ByteArrayOutputStream;  
    import java.io.IOException;  
    import java.io.InputStream;  
    import java.io.InputStreamReader;  
    import java.io.PrintWriter;  
    import java.net.HttpURLConnection;  
    import java.net.URL;  

    /** 
     * 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~

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