android 之HttpURLConnection的post,get方式请求数据

get方式和post方式的区别：

1.请求的URL地址不同：
　　post："http://xx:8081//servlet/LoginServlet"
　　get：http://xxx:8081//servlet/LoginServlet?username=root&pwd=123

2.请求头不同：
　　****post方式多了几个请求头：Content-Length   ,   Cache-Control , Origin

　　　　openConnection.setRequestProperty("Content-Length", body.length()+"");
　　　　openConnection.setRequestProperty("Cache-Control", "max-age=0");
　　　　openConnection.setRequestProperty("Origin", "http://xx:8081");

　　****post方式还多了请求的内容：username=root&pwd=123

　　　　//设置UrlConnection可以写请求的内容
　　　　openConnection.setDoOutput(true);
　　　　//获取一个outputstream，并将内容写入该流
　　　　openConnection.getOutputStream().write(body.getBytes());

3.请求时携带的内容大小不同
　　get:1k 
　　post:理论无限制

登录的布局文件

<?xml version="1.0" encoding="utf-8"?>
<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="com.example.yb.myapplication.MainActivity">

    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/input_username"
        android:hint="@string/input_username"/>

    <EditText
        android:layout_marginTop="10dp"
        android:layout_marginBottom="10dp"
        android:inputType="textPassword"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/input_password"
        android:hint="@string/input_password"/>

    <RelativeLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content">
        <CheckBox
            android:layout_marginLeft="30dp"
            android:layout_centerVertical="true"
            android:layout_alignParentLeft="true"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/cb_rem"
            android:text="@string/reme_password"/>

        <Button
            android:layout_marginRight="30dp"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:layout_alignParentRight="true"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bt_login"
            android:text="@string/bt_login"/>
    </RelativeLayout>
</LinearLayout>

登录的Activity代码

public class GetPostActivity extends AppCompatActivity {
    private EditText et_username;
    private EditText et_password;
    private CheckBox cb_rem;
    private Button bt_login;
    private Context mcontext;
    private String username;
    private String password;
    private boolean isRem;

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

        et_username = (EditText) findViewById(R.id.input_username);
        et_password = (EditText) findViewById(R.id.input_password);
        cb_rem = (CheckBox) findViewById(R.id.cb_rem);
        bt_login = (Button) findViewById(R.id.bt_login);
        bt_login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                login();
            }
        });
    }

    //创建一个handler
    Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            boolean isloginsuccess = (boolean) msg.obj;

            if (isloginsuccess) {
                //判断是否记住密码,要保存到本地，封装成方法
                if (isRem) {
                    //保存用户名和密码
                    boolean result = UserInfoUtil.saveUserInfo(mcontext, username, password);
                    if (result) {
                        Toast.makeText(getApplicationContext(), "用户名和密码保存成功", Toast.LENGTH_SHORT).show();
                    } else {
                        Toast.makeText(getApplicationContext(), "用户名和密码保存失败", Toast.LENGTH_SHORT).show();
                    }
                } else {
                    Toast.makeText(getApplicationContext(), "登录成功", Toast.LENGTH_SHORT).show();
                }
            } else {
                Toast.makeText(getApplicationContext(), "登录失败", Toast.LENGTH_SHORT).show();
            }
        }
    };

    public void login() {
        username = et_username.getText().toString().trim();
        password = et_password.getText().toString().trim();
        isRem = cb_rem.isChecked();
        //判断是否密码或者用户名为空
        if (TextUtils.isEmpty(username) || TextUtils.isEmpty(password)) {
            Toast.makeText(this, "用户名和密码不能为空", Toast.LENGTH_SHORT).show();
            return;
        }

        //post方法登录是否成功
        LoginHttpUtil.requestNetForGetLogin(handler, username, password);
    }
}

新建一个Net包，处理网络请求的操作，新建一个loginhttputil.java

public class LoginHttpUtil {
    //get方式登录
    public static void requestNetForGetLogin(final Handler handler,final String username,final String password) {

        //在子线程中操作网络请求
        new Thread(new Runnable() {
            @Override
            public void run() {
                //urlConnection请求服务器，验证
                try {
                    //1：url对象
                    URL url = new URL("http://192.168.1.100:8081//servlet/LoginServlet?username=" + URLEncoder.encode(username)+ "&pwd=" +  URLEncoder.encode(password) + "");
                    //2;url.openconnection
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                    //3
                    conn.setRequestMethod("GET");
                    conn.setConnectTimeout(10 * 1000);
                    //4
                    int code = conn.getResponseCode();
                    if (code == 200) {
                        InputStream inputStream = conn.getInputStream();
                        String result = StreamUtil.stremToString(inputStream);
                        System.out.println("=====================服务器返回的信息：：" + result);
                        boolean isLoginsuccess=false;
                        if (result.contains("success")) {
                            isLoginsuccess=true;
                        }
                        Message msg = Message.obtain();
                        msg.obj=isLoginsuccess;
                        handler.sendMessage(msg);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    //post方式登录
    public static void requestNetForPOSTLogin(final Handler handler,final String username,final String password) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                //urlConnection请求服务器，验证
                try {
                    //1：url对象
                    URL url = new URL("http://192.168.1.100:8081//servlet/LoginServlet");

                    //2;url.openconnection
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();

                    //3设置请求参数
                    conn.setRequestMethod("POST");
                    conn.setConnectTimeout(10 * 1000);
                    //请求头的信息
                    String body = "username=" + URLEncoder.encode(username) + "&pwd=" + URLEncoder.encode(password);
                    conn.setRequestProperty("Content-Length", String.valueOf(body.length()));
                    conn.setRequestProperty("Cache-Control", "max-age=0");
                    conn.setRequestProperty("Origin", "http://192.168.1.100:8081");

                    //设置conn可以写请求的内容
                    conn.setDoOutput(true);
                    conn.getOutputStream().write(body.getBytes());

                    //4响应码
                    int code = conn.getResponseCode();
                    if (code == 200) {
                        InputStream inputStream = conn.getInputStream();
                        String result = StreamUtil.stremToString(inputStream);
                        System.out.println("=====================服务器返回的信息：：" + result);
                        boolean isLoginsuccess=false;
                        if (result.contains("success")) {
                            isLoginsuccess=true;
                        }
                        Message msg = Message.obtain();
                        msg.obj=isLoginsuccess;
                        handler.sendMessage(msg);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }
}

二：get方式提交数据时候出现乱码的情况l;解决办法如下：

　　一般在开发客户端和服务端的编码要保持一致。

　　　　android端的默认编码是utf-8;

　　　　做url请求时需要对参数进行URLEncode编码.

　　　　URL url = new URL("http://xx:8081/servlet/LoginServlet?username="+URLEncoder.encode(username)+"&pwd="+URLEncoder.encode(password))

# 2. 　　post方式提交数据乱码解决
　　

  String body = "username=" + URLEncoder.encode(username) + "&pwd=" + URLEncoder.encode(password);