【Android-网络通讯】 客户端与.Net服务端Http通讯

以登陆系统为例：

一、创建服务端程序

1、打开VS2012，新建项目，创建ASP.NET WEB应用程序 ，命名为MyApp

2、添加新建项，选择一般处理程序，创建Login.ashx

C# Code：  Login.ashx

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace MyApp.Remote
{
    /// <summary>
    /// Login 的摘要说明
    /// </summary>
    public class Login : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            switch (context.Request["type"])
            {
                case "login":
                    loginValidate(context);
                    break;
                default:
                    break;
            }
        }

        /// <summary>
        /// 验证登陆
        /// </summary>
        /// <param name="context"></param>
        private void loginValidate(HttpContext context)
        {
            string account = context.Request["Account"].ToString();
            string password = context.Request["Password"].ToString();
            if (account == "" && password == "")
            {
                string realName="HelloWord";
                context.Response.Write("{\"Result\":\"1\",\"RealName\":\""+realName+"\"}");
                //实际输出：{"Result":"1","RealName":"HelloWord"}
                //注意：双引号需要用转义符\
            }
            else
            {
                context.Response.Write("{\"Result\":\"0\"}");
            }

        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

3、到这里就完成服务端的验证代码登陆了。

浏览器输入地址访问：http://localhost:11946/Remote/Login.ashx?type=login&Account=123&Password=123

4、这时候程序还没有部署到IIS，那么如何在VS调试的时候，客户端可以通过IP访问该程序？

客户端通过IP和端口访问服务端程序

二、创建客户端程序

1、界面布局 layout \ activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_margin="10dp"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TextView
            android:layout_width="100dp"
            android:layout_height="wrap_content"
            android:text="账号" />

        <EditText
            android:id="@+id/edittext_loginAccount"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="number" >

            <requestFocus />
        </EditText>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TextView
            android:layout_width="100dp"
            android:layout_height="wrap_content"
            android:text="密码" />

        <EditText
            android:id="@+id/editetext_loginPassword"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:ems="10"
            android:inputType="textPassword" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center" >

        <CheckBox
            android:id="@+id/checkbox_remindPassword"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="记住密码" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center" >

        <Button
            android:id="@+id/button_login"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="登录" />
    </LinearLayout>

</LinearLayout>

2、Java Code : MainActivity.java

package com.example.net;

import java.io.BufferedReader;
import java.io.InputStreamReader;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONObject;

import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.os.StrictMode;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    private String ServerUrl = "http://192.168.137.210:11946/Remote/";
    private EditText et_loginAccount;
    private EditText et_loginPassword;
    private CheckBox cb_remindPassword;
    private Button btn_login;
    private ProgressDialog progressDialog;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
        StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectLeakedSqlLiteObjects().detectLeakedClosableObjects().penaltyLog().penaltyDeath().build());

        et_loginAccount = (EditText) findViewById(R.id.edittext_loginAccount);
        et_loginPassword = (EditText) findViewById(R.id.editetext_loginPassword);
        cb_remindPassword = (CheckBox) findViewById(R.id.checkbox_remindPassword);
        btn_login = (Button) findViewById(R.id.button_login);

        btn_login.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // loading 对话框
                progressDialog = ProgressDialog.show(MainActivity.this, "", "服务器连接中...", true, false);
                // 开启线程去验证登录
                new Thread() {
                    @Override
                    public void run() {
                        // 向handler发消息
                        mHandler.sendEmptyMessage(0);
                    }
                }.start();
            }
        });

    }

    private Handler mHandler = new Handler() {

        @Override
        public void handleMessage(Message msg) {
            // 登录验证
            loginValidate();
        }

    };

    private void loginValidate() {
        // 打开网络连接
        HttpClient client = new DefaultHttpClient();
        StringBuilder builder = new StringBuilder();
        // 服务器提交地址
        String url = ServerUrl + "Login.ashx?type=login&Account=" + et_loginAccount.getText().toString() + "&Password=" + et_loginPassword.getText().toString();
        HttpGet httpGet = new HttpGet(url);
        try {
            HttpResponse response = client.execute(httpGet);
            BufferedReader reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
            // 填充数据流
            for (String s = reader.readLine(); s != null; s = reader.readLine()) {
                builder.append(s);
            }
            // 读取Json返回数组
            JSONObject jsonObject = new JSONObject(builder.toString());
            String re_result = jsonObject.getString("Result");
            String re_realName = jsonObject.getString("RealName");
            if (re_result.equals("1")) {
                Toast.makeText(MainActivity.this, "验证成功!" + re_realName, Toast.LENGTH_SHORT).show();
                // TODO:跳转页面
            } else {
                Toast.makeText(MainActivity.this, "登录失败", Toast.LENGTH_SHORT).show();
            }
            progressDialog.dismiss();
        } catch (Exception e) {
            e.printStackTrace();
            Toast.makeText(MainActivity.this, "服务器数据读取失败", Toast.LENGTH_SHORT).show();
            progressDialog.dismiss();
        }
    }

}

StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder().detectDiskReads().detectDiskWrites().detectNetwork().penaltyLog().build());
StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().detectLeakedSqlLiteObjects().detectLeakedClosableObjects().penaltyLog().penaltyDeath().build());

少了上面两句代码会报错android.os.NetworkOnMainThreadException即，在主线程访问网络时出的异常

Android在4.0之前的版本支持在主线程中访问网络，但是在4.0以后对这部分程序进行了优化，也就是说访问网络的代码不能写在主线程中了。

稍后研究多线程

3、别放了加上权限 AndroidManifest.xml

  <!-- sd卡读取权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" />

    <!-- 访问网络权限 -->
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />

    <!-- 完全退出程序权限 -->
    <uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />