(五) android基础介绍

01_使用POST方式提交数据时的中文乱码解决方法（重点）

   解决办法：使用客户端和服务器两边的字符集编码保持一致。 UTF-8，

02_使用GET方式提交数据的中文乱码的解决方法

    使用URLEncoder.encode(name,"UTF-8")进行url编码：
    String path = "http://192.168.22.136:8080/web/servlet/LoginServlet?username="+URLEncoder.encode(name,"UTF-8")+"&password="+URLEncoder.encode(pwd,"UTF-8");

03_使用httpclient提交数据（重点）  

   apache httpClient 轻量级的浏览器

* 使用GET方式数据步骤：

 1、创建一个浏览器：
    
       2、输入一个网址：
    
       3、敲回车
    
       模块代码：

        package com.itheima.qqlogin;
    
        import java.io.InputStream;
        import java.net.HttpURLConnection;
        import java.net.URL;
        import java.net.URLEncoder;
        
        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 com.itheima.htmlview.utils.StreamTools;      
        
        import android.app.Activity;
        import android.os.Bundle;
        import android.text.TextUtils;
        import android.view.View;
        import android.widget.EditText;
        import android.widget.Toast;
        
        public class MainActivity extends Activity {
    
        private EditText et_name;
    
        private EditText et_pwd;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            
            et_name = (EditText) findViewById(R.id.et_name);
    
            et_pwd = (EditText) findViewById(R.id.et_pwd);
        
        }
    
        public void login(View view){
            final String name = et_qq.getText().toString().trim();
            
            final String pwd = et_pwd.getText().toString().trim();
            
            if(TextUtils.isEmpty(name) || TextUtils.isEmpty(pwd)){
                Toast.makeText(this, "qq和密码不能空", 0).show();
                return;
            }else{
                new Thread(){
                    
                    public void run() {
                        
                        try {
                            String path = "http://192.168.22.136:8080/web/servlet/LoginServlet?username="+URLEncoder.encode(name,"UTF-8")+"&password="+URLEncoder.encode(pwd,"UTF-8");
    //                    
    //                         1、创建一个浏览器：
    
                            HttpClient client = new DefaultHttpClient();
    //                           2、输入一个网址：
                            HttpGet httpGet = new HttpGet(path);
    //
    //                           3、敲回车
                            HttpResponse response = client.execute(httpGet);
                            //获取服务器端返回的响应码（状态码）
                            int code =     response.getStatusLine().getStatusCode();
    //                         int code = conn.getResponseCode();
                             if(code == 200){
    //                            （2）解析服务器返回的二进制数据，解析成一个字符串
    //                             InputStream is = conn.getInputStream();
                                 //获取服务器返回的二进制数据流
                                 InputStream is = response.getEntity().getContent();
                                 
                                 String result = StreamTools.readStream(is);
                                 System.out.println("---------"+ result);
                             }
    
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    };
                }.start();
            }
        }
         
    }

使用post方式向服务器端提交数据

      1、创建一个浏览器：
    
       2、输入一个网址：
    
       3、敲回车

 模版代码：
  

  package com.itheima.qqlogin;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import com.itheima.htmlview.utils.StreamTools;

public class MainActivity extends Activity {

    private EditText et_qq;

    private EditText et_pwd;
    
    private Handler handler = new Handler(){
        public void handleMessage(android.os.Message msg) {
            
            String result = (String) msg.obj;
            
            Toast.makeText(MainActivity.this, result, 0).show();
        };
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_qq = (EditText) findViewById(R.id.et_qq);

        et_pwd = (EditText) findViewById(R.id.et_pwd);
    
    }

    public void login(View view){
        final String name = et_qq.getText().toString().trim();
        
        final String pwd = et_pwd.getText().toString().trim();
        
        if(TextUtils.isEmpty(name) || TextUtils.isEmpty(pwd)){
            Toast.makeText(this, "qq和密码不能空", 0).show();
            return;
        }else{
            new Thread(){
                
                public void run() {
                    
                    try {
                        String path = "http://192.168.22.136:8080/web/servlet/LoginServlet";
//                        String data = "username="+name+"&password="+pwd;
                        
                        String data = "username="+URLEncoder.encode(name,"UTF-8")+"&password="+URLEncoder.encode(pwd,"UTF-8");
                        
//                           1、创建一个浏览器：

                        HttpClient client = new DefaultHttpClient();
//                           2、输入一个网址：
                        HttpPost httpPost = new HttpPost(path);
                        
                        
                        List<BasicNameValuePair> parameters = new ArrayList<BasicNameValuePair>();
                        
                        BasicNameValuePair p1 = new BasicNameValuePair("username", name);
                        
                        BasicNameValuePair p2 = new BasicNameValuePair("password", pwd);
                        parameters.add(p1);
                        parameters.add(p2);
                        //默认使用iso-8859-1编码，需要指定UTF-8
                        UrlEncodedFormEntity entity = new UrlEncodedFormEntity(parameters,"UTF-8");
                        
                        
//
//                           3、敲回车
                        //设置提交的数据
                        httpPost.setEntity(entity);
                        HttpResponse  response = client.execute(httpPost);
                         
//                   2、服务器返回数据
//                    （1）判断状态码：200 ok，404 没有找到资源、503、509 服务器端错误
                         int code =  response.getStatusLine().getStatusCode();
//                         int code = conn.getResponseCode();
                         if(code == 200){
//                            （2）解析服务器返回的二进制数据，解析成一个字符串
                             InputStream is = response.getEntity().getContent();
                             
                             
                             String result = StreamTools.readStream(is);
                             System.out.println("---------"+ result);
                             
                             Message msg = Message.obtain();
                             msg.obj = result;
                             handler.sendMessage(msg);
                         }

                        
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                };
            }.start();
        }
    }
     
    }

04_使用Aynchttpclient向服务器端提交数据（重点）

     1、创建一个浏览器：
    
       2、输入一个网址：
    
       3、敲回车
        

package com.itheima.qqlogin;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

import org.apache.http.Header;

import com.itheima.htmlview.utils.StreamTools;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;



import android.app.Activity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    private EditText et_name;

    private EditText et_name;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_qq = (EditText) findViewById(R.id.et_qq);

        et_pwd = (EditText) findViewById(R.id.et_pwd);
    
    }

    public void login(View view){
        final String name = et_qq.getText().toString().trim();
        
        final String pwd = et_pwd.getText().toString().trim();
        
        if(TextUtils.isEmpty(name) || TextUtils.isEmpty(pwd)){
            Toast.makeText(this, "qq和密码不能空", 0).show();
            return;
        }else{
            
                    
                    try {
                        String path = "http://192.168.22.136:8080/web/servlet/LoginServlet?username="+URLEncoder.encode(name,"UTF-8")+"&password="+URLEncoder.encode(pwd,"UTF-8");
                        //1、创建一个浏览器： 
                        AsyncHttpClient client = new AsyncHttpClient();
//                        1、输入网址，调用get方式向服务器发送请求：
                          client.get(path, new AsyncHttpResponseHandler() {
                            
                              /*
                               * 请求成功，服务器端正常响应 响应码200
                               * statusCode 响应码200ok，404没有找到资源，503服务器内部错误, Header[] headers 响应头信息, byte[] responseBody 服务器返回的数据
                               */
                            @Override
                            public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
                                Toast.makeText(MainActivity.this, new String(responseBody), 0).show();
                            }
                            
                              /*
                             * 请求成功，服务器端正常响应 响应码200
                             * int statusCode, Header[] headers, byte[] responseBody, Throwable error
                             * statusCode 响应码200ok，404没有找到资源，503服务器内部错误, Header[] headers 响应头信息, byte[] responseBody 服务器返回的数据
                             * Throwable error 服务器端返回的异常
                             */
                            @Override
                            public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable arg3) {
                                Toast.makeText(MainActivity.this, new String(responseBody), 0).show();
                            }
                        });
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                };
            
        }
    }

 使用POST方式向服务器端提交数据    

package com.itheima.qqlogin;

import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;

import org.apache.http.Header;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

import com.itheima.htmlview.utils.StreamTools;
import com.loopj.android.http.AsyncHttpClient;
import com.loopj.android.http.AsyncHttpResponseHandler;
import com.loopj.android.http.RequestParams;

public class MainActivity extends Activity {

    private EditText et_qq;

    private EditText et_pwd;
    
    private Handler handler = new Handler(){
        public void handleMessage(android.os.Message msg) {
            
            String result = (String) msg.obj;
            
            Toast.makeText(MainActivity.this, result, 0).show();
        };
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_qq = (EditText) findViewById(R.id.et_qq);

        et_pwd = (EditText) findViewById(R.id.et_pwd);
    
    }

    public void login(View view){
        final String name = et_qq.getText().toString().trim();
        
        final String pwd = et_pwd.getText().toString().trim();
        
        if(TextUtils.isEmpty(name) || TextUtils.isEmpty(pwd)){
            Toast.makeText(this, "qq和密码不能空", 0).show();
            return;
        }else{
            try {
                String path = "http://192.168.22.136:8080/web/servlet/LoginServlet";
//            String data = "username="+name+"&password="+pwd;
                
//                String data = "username="+URLEncoder.encode(name,"UTF-8")+"&password="+URLEncoder.encode(pwd,"UTF-8");
//                1、创建一个浏览器：
                AsyncHttpClient client = new AsyncHttpClient();
            
                
//                 2、输入一个网址,敲回车：
                RequestParams params = new RequestParams();
                params.put("username", name);
                params.put("password", pwd);
                
                client.post(path, params, new AsyncHttpResponseHandler() {
                    
                    @Override
                    public void onSuccess(int statusCode, Header[] headers, byte[] responseBody) {
                        Toast.makeText(MainActivity.this, new String(responseBody), 0).show();
                        
                    }
                    
                    @Override
                    public void onFailure(int statusCode, Header[] headers, byte[] responseBody, Throwable e) {
                        Toast.makeText(MainActivity.this, new String("服务器端返回数据失败"), 0).show();
                    }
                });
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
     
}

05_多线程下载的原理

线程可以理解为下载的通道，一个线程就是一个文件的下载通道，
多线程也就是同时开起好几个下载通道.当服务器提供下载服务时，
使用下载者是共享带宽的，在优先级相同的情况下，
总服务器会对总下载线程进行平均分配。
不难理解，
如果你线程多的话，那下载的越快。现流行的下载软件都支持多线程。

06_javase实现多线程

  步骤：
    1、在客户端创建一个与服务器端大小一样的空白文件
    2、设置子线程的个数
    3、计算每个子线程下载的数据块大小和下载起始位置、结束位置
    4、创建子线程开始下载数据
    5、得到每个子线程都下载完成的标记

代码：
MultiThreadDownLoader.java:

    import java.io.RandomAccessFile;
    import java.net.HttpURLConnection;
    import java.net.URL;


    public class MultiThreadDownLoader {

    //2、使用的子线程的个数
    private static int threadCount =3;
    
    /**
     * @param args
     */
    public static void main(String[] args) {
        try {
            String path = "http://192.168.22.136:8080/sogou.exe";
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(3000);
            
            int code = conn.getResponseCode();
            if(code == 200){
            int length =    conn.getContentLength();
            //1、在客户端创建一个与服务端文件一样大小的文件
            RandomAccessFile file = new RandomAccessFile("temp.exe", "rw");
            file.setLength(length);
            //3、每个子线程下载数据块 ,下载的起始位置和结束位置
            int blockSize = length/threadCount;
            
            // threadId * blockSize  ---- （threadId+1）* blockSize -1
            for(int threadId =0; threadId < threadCount; threadId++){
                //下载的起始位置和结束位置
                int startIndex = threadId * blockSize;
                int endIndex = 0;
                
                if(threadId != (threadCount -1)){
                     endIndex = (threadId + 1) * blockSize - 1;
                }else{
                    endIndex = length-1;
                }
                
                //开启子线程下载数据
                new ThreadDownLoader(path, startIndex, endIndex, threadId, threadCount).start();
                
            }
                
            }else{
                //抛出异常
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    }

ThreadDownLoader.java:

    import java.io.InputStream;
    import java.io.RandomAccessFile;
    import java.net.HttpURLConnection;
    import java.net.URL;


    public class ThreadDownLoader extends Thread {

    private String path;
    private int startIndex;
    private int endIndex;
    private int threadId;
    private int threadCount;
    //正在运行的线程个数
    private static  int runningThreadCount = 3; 
    ThreadDownLoader(String path,int startIndex,int endIndex,int threadId,int threadCount){
        this.path = path;
        this.startIndex = startIndex;
        this.endIndex = endIndex;
        this.threadId = threadId;
        this.threadCount = threadCount;
        
    }
    
    @Override
        public void run() {
          downLoad(path,startIndex,endIndex,threadId,threadCount);
        }
    
    
    public void downLoad(String path,int startIndex,int endIndex,int threadId,int threadCount)
     {
      try {
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(3000);
            //设置子线程请求数据的范围
            conn.setRequestProperty("Range", "bytes="+startIndex+"-"+endIndex);
            int code = conn.getResponseCode();
            if(code == 206){//请求部分数据
                
             InputStream is = conn.getInputStream();
              RandomAccessFile file = new RandomAccessFile("temp.exe","rw");
              //指定从哪个位置开始写数据
              file.seek(startIndex);
              
               byte[] buffer = new byte[1024];
              int len = -1;
              while((len = is.read(buffer)) != -1){
                  file.write(buffer, 0, len);
              }
              
              file.close();
              System.out.println("线程"+threadId+"下载完成...............");
              synchronized (ThreadDownLoader.this) {
                  runningThreadCount--;
                  if(runningThreadCount == 0){
                      System.out.println("文件下载完成...............");
                  }
            }
            }
    } catch (Exception e) {
         System.out.println("线程"+threadId+"下载失败...............");
        e.printStackTrace();
    }
      
    }

    }

07_断点续传下载

   1、实时记录线程下载的位置；
   2、接上一次下载的位置继续下载；
    代码：    

 import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.channels.ReadableByteChannel;


public class ThreadDownLoader extends Thread {

    private String path;
    private int startIndex;
    private int endIndex;
    private int threadId;
    private int threadCount;
    //正在运行的线程个数
    private static  int runningThreadCount = 3; 
    ThreadDownLoader(String path,int startIndex,int endIndex,int threadId,int threadCount){
        this.path = path;
        this.startIndex = startIndex;
        this.endIndex = endIndex;
        this.threadId = threadId;
        this.threadCount = threadCount;
        
    }
    
    @Override
        public void run() {
          downLoad(path,startIndex,endIndex,threadId,threadCount);
        }
    
    
  public void downLoad(String path,int startIndex,int endIndex,int threadId,int threadCount)
  {
      try {
            URL url = new URL(path);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(3000);
            
            //获取上一次下载的位置，接着下载
            File threadFile = new File(threadId+".txt");
            if(threadFile.exists() && threadFile.length() > 0){
                FileReader fr = new FileReader(threadFile);
                BufferedReader br = new BufferedReader(fr);
                String position = br.readLine();
                //设置子线程请求数据的范围
                conn.setRequestProperty("Range", "bytes="+position+"-"+endIndex);
                startIndex = Integer.valueOf(position);
            }else{
                //设置子线程请求数据的范围
                conn.setRequestProperty("Range", "bytes="+startIndex+"-"+endIndex);
            }
            
            
            int code = conn.getResponseCode();
            if(code == 206){//请求部分数据
                
             InputStream is = conn.getInputStream();
              RandomAccessFile file = new RandomAccessFile("temp.exe","rw");
              //指定从哪个位置开始写数据
              file.seek(startIndex);
              
               byte[] buffer = new byte[1024*1024];
              int len = -1;
              int total = 0;
              while((len = is.read(buffer)) != -1){
                  file.write(buffer, 0, len);
                  total = total + len;
                  int currentPosition = startIndex + total;
                  //能够即时的把数据写到数据
                  RandomAccessFile f = new RandomAccessFile(threadId+".txt", "rwd");
                  f.write((currentPosition+"").getBytes());
                  f.close();
                  
              }
              
              file.close();
              System.out.println("线程"+threadId+"下载完成...............");
              synchronized (ThreadDownLoader.this) {
                  runningThreadCount--;
                  if(runningThreadCount == 0){
                      System.out.println("文件下载完成...............");
                  }
            }
            }
    } catch (Exception e) {
         System.out.println("线程"+threadId+"下载失败...............");
        e.printStackTrace();
    }
      
  }

    }

08_多线程下载移植到Android项目上（重点）

1、设置布局文件：

<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:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入下载的文件网络地址"
        android:id="@+id/et_path" />
    
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="开启几个子线程加速下载"
        android:text="3"
        android:id="@+id/et_threadCount" />
    
    <Button 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="下载"
        android:onClick="downLoad"
        />

    </LinearLayout>

2、修改代码：

MainActivity.java:

  package com.itheima.multithreaddownload;

    import java.io.RandomAccessFile;
    import java.net.HttpURLConnection;
    import java.net.URL; 
    import android.app.Activity;
    import android.os.Bundle;
    import android.os.Environment;
    import android.text.TextUtils;
    import android.view.View;
    import android.widget.EditText;
    import android.widget.Toast;
    public class MainActivity extends Activity {

    private EditText et_path;
    private EditText et_threadCount;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        et_path = (EditText) findViewById(R.id.et_path);

        et_threadCount = (EditText) findViewById(R.id.et_threadCount);
    }
    
    public void downLoad(View view){
        
        final String path = et_path.getText().toString().trim();
        

        String threadCountStr = et_threadCount.getText().toString().trim();
        
        
        
        if(TextUtils.isEmpty(path) || TextUtils.isEmpty(threadCountStr)){
            
            Toast.makeText(this, "下载地址或线程个数不能为空", 0).show();
            return;
        }else{
            //
            final int threadCount = Integer.valueOf(threadCountStr);
            
            new Thread(){
                
                public void run() {
                    try {
    //                        String path = "http://192.168.22.136:8080/sogou.exe";
                        URL url = new URL(path);
                        
                        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                        
                        conn.setRequestMethod("GET");
                        conn.setConnectTimeout(3000);
                        
                        int code = conn.getResponseCode();
                        if(code == 200){
                        int length =    conn.getContentLength();
                        //1、在客户端创建一个与服务端文件一样大小的文件
                        RandomAccessFile file = new RandomAccessFile(Environment.getExternalStorageDirectory()+"/temp.exe", "rw");
                        file.setLength(length);
                        //3、每个子线程下载数据块 ,下载的起始位置和结束位置
                        int blockSize = length/threadCount;
                        
                        // threadId * blockSize  ---- （threadId+1）* blockSize -1
                        for(int threadId =0; threadId < threadCount; threadId++){
                            //下载的起始位置和结束位置
                            int startIndex = threadId * blockSize;
                            int endIndex = 0;
                            
                            if(threadId != (threadCount -1)){
                                 endIndex = (threadId + 1) * blockSize - 1;
                            }else{
                                endIndex = length-1;
                            }
                            
                            //开启子线程下载数据
                            new ThreadDownLoader(path, startIndex, endIndex, threadId, threadCount).start();
                            
                        }
                        
                            
                        }else{
                            //抛出异常
                        }
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                };
            }.start();
        }
    }

    }

##09_使用xutils实现多线程下载（重点）

1. 导入xutils包 
2. 初始化httputils对象

         HttpUtils http = new HttpUtils();


         /**
         * 2 进行下载 
         * url 下载的路径
         * target 存放目标地址 
         * autoResume  是否支持断点续传下载 
         */
        http.download(path, "/mnt/sdcard/feiq.exe", true, new RequestCallBack<File>() {
            
            //下载成功的回调
            @Override
            public void onSuccess(ResponseInfo<File> responseInfo) {
                Toast.makeText(getApplicationContext(), "下载成功", 0).show();
                
            }
            
            //下载失败的回调
            @Override
            public void onFailure(HttpException error, String msg) {
            }
            //当前进度 
            @Override
            public void onLoading(long total, long current, boolean isUploading) {
                
                pb.setMax((int) total); //设置进度条的最大值
                pb.setProgress((int) current);
                
                super.onLoading(total, current, isUploading);
            }
            
        });