12_Android中HttpClient的应用，doGet,doPost,doHttpClientGet,doHttpClient请求，另外借助第三方框架实现网络连接的应用，

准备条件，

编写一个web项目。编写一个servlet，若用户名为lisi,密码为123，则返回“登录成功”，否则”登录失败”。项目名为ServerItheima28。代码如下：

package com.itheima28.servlet;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class LoginServlet extends HttpServlet {

/**

* The doGet method of the servlet. <br>

* This method is called when a form has its tag value method equals to get.

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

String username = request.getParameter("username"); // 采用的编码是: iso-8859-1

String password = request.getParameter("password");

// 采用iso8859-1的编码对姓名进行逆转, 转换成字节数组, 再使用utf-8编码对数据进行转换, 字符串

username = new String(username.getBytes("iso8859-1"), "utf-8");

password = new String(password.getBytes("iso8859-1"), "utf-8");

System.out.println("姓名: " + username);

System.out.println("密码: " + password);

if("lisi".equals(username) && "123".equals(password)) {

* getBytes 默认情况下, 使用的iso8859-1的编码, 但如果发现码表中没有当前字符,

* 会使用当前系统下的默认编码: GBK

response.getOutputStream().write("登录成功".getBytes("utf-8"));

} else {

response.getOutputStream().write("登录失败".getBytes("utf-8"));

}

/**

* The doPost method of the servlet. <br>

* This method is called when a form has its tag value method equals to post.

* @param request the request send by the client to the server

* @param response the response send by the server to the client

* @throws ServletException if an error occurred

* @throws IOException if an error occurred

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

System.out.println("doPost");

doGet(request, response);

}

使用github上的android-async-http-master框架：

2 编写Android应用，应用截图如下：

代码结构如下：

清单文件

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.itheim28.submitdata"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="8"

android:targetSdkVersion="19" />

<uses-permission android:name="android.permission.INTERNET"/>

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="com.itheim28.submitdata.MainActivity"

android:label="@string/app_name" >

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

3 编写布局文件activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

tools:context=".MainActivity" >

<EditText

android:id="@+id/et_username"

android:layout_width="fill_parent"