安卓端登录与web后台相连

1.首先在后台端简单写xml，按着QQ的登录界面即可

2.在Main方法中

import android.os.Looper;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.view.Window;import android.widget.Button;import android.widget.EditText;import android.widget.Toast;import shangguigu.java.checkloding_fanny_android.R;import shangguigu.java.checkloding_fanny_android.shangguigu.java.checkloding_domain.shangguigu.java.User;import shangguigu.java.checkloding_fanny_android.shangguigu.java.checkloding_manager.CheckLoding;public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private EditText et_main_username;    private EditText et_main_password;    private Button btn_main_loding;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        requestWindowFeature(Window.FEATURE_NO_TITLE);        setContentView(R.layout.activity_main);        init();        data();    }    private void data() {        btn_main_loding.setOnClickListener(this);    }    private void init() {        et_main_username = (EditText) findViewById(R.id.et_main_username);        et_main_password = (EditText) findViewById(R.id.et_main_password);        btn_main_loding = (Button) findViewById(R.id.btn_main_loding);    }    @Override    public void onClick(View v) {        if (v == btn_main_loding) {            final String username = et_main_username.getText().toString();            final String password = et_main_password.getText().toString();            if (username.equals("")||password.equals("")) {                Toast.makeText(this, "用户名或密码为空", Toast.LENGTH_SHORT).show();                return;            }            new  Thread(new Runnable() {                @Override                public void run() {                    User user = CheckLoding.checkLoding(username, password);                    if (user!=null) {                        Intent intent = new Intent(MainActivity.this,activity_menu.class);                        Bundle bundle = new Bundle();                        bundle.putSerializable("user",user);                        intent.putExtras(bundle);                        startActivity(intent);                    }else {                        Looper.prepare();                        Toast.makeText(MainActivity.this,"没有这个值",Toast.LENGTH_SHORT).show();                    }                }            }).start();        }    }}

3.需要创建一个封装类，实现Serializable接口也只是拥有三个属性，username，password，id4.需要创建一个实现登录的方法，我们把这个方法定义在一个登录的类里

import org.json.JSONArray;import org.json.JSONObject;import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;import java.net.HttpURLConnection;import java.net.URL;import shangguigu.java.checkloding_fanny_android.shangguigu.java.checkloding_domain.shangguigu.java.User;/** * Created by Dell on 2016/8/9. */public class CheckLoding {    public static User checkLoding (String username,String password) {        User user = null;        try {            URL url = new URL("http://192.168.51.5:8080/student_webforandroid/checkLodingforAndroid");            HttpURLConnection connection = (HttpURLConnection) url.openConnection();            connection.setRequestMethod("POST");            connection.setDoOutput(true);            connection.setDoInput(true);            connection.setUseCaches(false);            connection.connect();            OutputStream os = connection.getOutputStream();            OutputStreamWriter osw = new OutputStreamWriter(os);            BufferedWriter bw = new BufferedWriter(osw);            JSONArray jsonArray = new JSONArray();            JSONObject jsonObject = new JSONObject();            jsonObject.put("username",username);            jsonObject.put("password",password);            jsonArray.put(jsonObject);            bw.write(jsonArray.toString());            bw.flush();            bw.close();            InputStream is = connection.getInputStream();            InputStreamReader isr = new InputStreamReader(is);            BufferedReader br = new BufferedReader(isr);            String userjson = br.readLine();            if (!userjson.equals("error")) {                JSONArray userJsonArray = new JSONArray(userjson);                JSONObject userJsonObject = userJsonArray.getJSONObject(0);                user = new User();                user.setId(userJsonObject.getInt("id"));                user.setUsername(userJsonObject.getString("username"));                user.setPassword(userJsonObject.getString("password"));            }            br.close();            connection.disconnect();        } catch (Exception e) {            e.printStackTrace();        }        return user;    }}

与web后台相连，因此需要一个servlet

<pre name="code" class="java">import java.io.BufferedReader;import java.io.BufferedWriter;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStream;import java.io.OutputStreamWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import com.fanny.domain.User;import com.fanny.managrimpl.StudentImpl;import com.fanny.managrimpl.StudentManager;public class checkLodingforAndroid extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");InputStream is = request.getInputStream();InputStreamReader isr = new InputStreamReader(is);BufferedReader br = new BufferedReader(isr);String json = br.readLine();//System.out.println(json);try {JSONArray jsonArray = new JSONArray(json);JSONObject jsonObject =jsonArray.getJSONObject(0);String username = jsonObject.getString("username");String password = jsonObject.getString("password");User user = null;StudentManager sm = new StudentImpl();user = sm.CheckLoging(username, password);System.out.println(user);if (user!=null) {JSONArray jsonArray2 = new JSONArray();JSONObject jsonObject2 = new JSONObject();jsonObject2.put("username", username);jsonObject2.put("password", password);jsonObject2.put("id", user.getId());jsonArray2.put(jsonObject2);//传送给安卓OutputStream os = response.getOutputStream();OutputStreamWriter osw = new OutputStreamWriter(os);BufferedWriter bw = new BufferedWriter(osw);bw.write(jsonArray2.toString());bw.flush();bw.close();} else {OutputStream os = response.getOutputStream();OutputStreamWriter osw = new OutputStreamWriter(os);BufferedWriter bw = new BufferedWriter(osw);bw.write("error");bw.flush();bw.close();}} catch (JSONException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

登录成功后会需要显示，所以要新建一个activity，进行带参传递

</pre><pre code_snippet_id="1822449" snippet_file_name="blog_20160811_6_3116162" name="code" class="java">import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.Window;import android.widget.TextView;import shangguigu.java.checkloding_fanny_android.R;import shangguigu.java.checkloding_fanny_android.shangguigu.java.checkloding_domain.shangguigu.java.User;public class Result extends AppCompatActivity {    private TextView tv_id;    private TextView tv_username;    private TextView tv_password;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        this.requestWindowFeature(Window.FEATURE_NO_TITLE);        setContentView(R.layout.activity_result);        init();        indata();    }    private void indata() {        User user = (User) getIntent().getSerializableExtra("user");        if (user!=null) {            int id = user.getId();            String username = user.getUsername();            String password = user.getPassword();            tv_id.setText(id+"");            tv_username.setText(username);            tv_password.setText(password);        }    }    private void init() {        tv_id = (TextView) findViewById(R.id.tv_id);        tv_username = (TextView) findViewById(R.id.tv_username);        tv_password = (TextView) findViewById(R.id.tv_password);    }}

主要涉及的知识点

安卓端与servlet的数据交互(HttpURLConnection)方式

字符流字节流的转换

Json的生成与解析

Activity的带参跳转

URL url = newURL("http://192.168.56.1:8080/LoginDemo/cn.edu.hpu.android/CheckAndroidLogin");
//建立Httpconnect并设置相关属性
HttpURLConnectionhttpURLConnection = (HttpURLConnection)url.openConnection();//建立对象
httpURLConnection.setDoOutput(true);//可以输出
httpURLConnection.setDoInput(true);//允许输入
httpURLConnection.setUseCaches(false);//不使用缓存
httpURLConnection.setRequestMethod("POST");//使用post传输
httpURLConnection.connect();//连接

OutputStreamos =httpURLConnection.getOutputStream();//得到连接的输出流
OutputStreamWriterosw =newOutputStreamWriter(os); );//转换成字符流
BufferedWriterbw =newBufferedWriter(osw);//批量传输

InputStream is =httpURLConnection.getInputStream();//得到输入流
InputStreamReaderisr =newInputStreamReader(is);//转换成字符流
BufferedReaderbr =newBufferedReader(isr);//批量读取

bw.write();//写入数据

br.readLine();//读取数据

生成

JSONArray jsonArray =newJSONArray();
JSONObjectobject =newJSONObject();
object.put("username",username);
object.put("password",password);
jsonArray.put(object);

解析

JSONArray userjsonarr =newJSONArray(userjson);
JSONObjectuserobj =userjsonarr.getJSONObject(0);
user = newUser();
user.setId(userobj.getInt("id"));
user.setUsername(userobj.getString("username"));
user.setPassword(userobj.getString("password"));

Activity之间的带参跳

第一种方法

Intentintent =newIntent(MainActivity.this,ResultActivity.class);
intent.putExtra(“id”user.getId());

intent.putExtra(“username”,user.getUsername());

intent.putExtra(“id”,user.getPassword());
startActivity(intent);

第二种方法

Intentintent =newIntent(MainActivity.this,ResultActivity.class);
Bundle bundle = new Bundle();
bundle.putSerializable(“user”,user);
intent.putExtras(bundle);
startActivity(intent);