android通过发送http请求与java后端进行响应 |
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android通过发送http请求与java后端进行响应
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背景：最近有同学需要服务端和安卓进行交流的需求，我在大二的时侯也在想java和安卓端是如何交接的，但因为当时水平有限，所以没能解决，也是一直把这件事情埋在心中，如今也在网上找到了一种方法，这种方法是用http请求进行交流，但是原来的博主一些细节没有交代清楚，我也踩了一些坑。不过原博主的代码还是挺好的，有需求的朋友可在原代码上进行拓展，如连接数据库、将数据显示到网页上。解决了安卓和java服务端的交接问题，这些拓展都是很容易去实现。这是原博主的博客原文http://blog.csdn.net/u012145166/article/details/51335187，下面我复制的代码的时候，我会把我遇到的坑一并介绍。这是源代码，直接到github上下载即可https://github.com/duantuigegelxh/AndroidAndJava。我使用的开发软件分别为idea和andorid stodio。 服务端：user这是一个javaBean类，在服务端和客户端分别有一个。 package bean; import java.io.Serializable; import java.util.Date; /** * JavaBean ,存储User上的 信息 */ public class User implements Serializable{ private int id; private String phoneNumber; private String password; private String userName; private String emailAddress; private Date registerTime; //用于URL传参和取参时的key public static String PHONENUMBER = "phoneNumber"; public static String PASSWORD = "passWord"; public static String USERNAME = "userName"; //构造函数 public User(String phoneNumber,String password,String userName){ this.phoneNumber = phoneNumber; this.password = password; this.userName = userName; registerTime = new Date(); } public User() { } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getPhoneNumber() { return phoneNumber; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getEmailAddress() { return emailAddress; } public void setEmailAddress(String emailAddress) { this.emailAddress = emailAddress; } public Date getRegisterTime() { return registerTime; } public void setRegisterTime(Date registerTime) { this.registerTime = registerTime; } }Dao层，这里是模拟从数据库里面取数据，自己可拓展与数据库连接实现增删改查等。 package bean; import java.util.ArrayList; /** *这个是模拟数据库的DAO层，如果用户和下面的phoneNumber(123456),password(abc123456)如果是一样的，就说明前端 * 传过来的数据是一样的，这个以后拓展成访问数据库 */ public class UserDAO { public static void main(String[] args) { UserDAO userDAO = new UserDAO(); System.out.println(userDAO.isLoginOK("123456", "abc123456")); } public ArrayList users; public UserDAO() { //这个相当于从数据库中查数据，可以自己拓展连接数据库，然后根据sql语句进行增删改查 // TODO Auto-generated constructor stub users = new ArrayList(); //这个相当于从数据库里面取到的数据，相当于之前注册了两个用户 users.add(new User("123456","abc123456","codingma")); users.add(new User("654321","abcdf123","codemayq")); } /** * 这个是验证登录信息是否正确的方法 * @param phoneNumber * @param password * @return */ public boolean isLoginOK(String phoneNumber,String password) { for (User user : users) { if (user.getPhoneNumber().equals(phoneNumber)) { if (user.getPassword().equals(password)) { return true; } } } return false; } }
servlet类，因为我使用了@WebSerlvet注解，所以可以不用在web.xml里面配置servlet package servlet; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import bean.User; import bean.UserDAO; /** * 这个是一个Servlet类 * * @WebServlet("/loginServlet")相当于在web.xml里面配置了servlet,这是一个注解 */ @WebServlet("/loginServlet") public class LoginServlet extends HttpServlet { /** * Constructor of the object. */ public LoginServlet() { super(); } /** * The doGet method of the servlet. *这个方法应该是作者用来测试这个servlet是否可行而编写的业务逻辑 * 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 { response.setContentType("text/html"); PrintWriter out = response.getWriter(); out.println(""); out.println(""); out.println(" A Servlet"); out.println(" "); out.print(" This is "); out.print(this.getClass()); out.println(", using the GET method"); out.println(" "); out.println(""); out.flush(); out.close(); } /** * The doPost method of the servlet. * * 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 { response.setContentType("text/html"); PrintWriter out = response.getWriter(); //这两个是获得android端传过来的数据 String phoneNumber = request.getParameter(User.PHONENUMBER); String passWord = request.getParameter(User.PASSWORD); //这个是初始化这个UserDao类，会先调用无参构造器 UserDAO userDAO = new UserDAO(); //OK和Wrong会在安卓端被接收到用来判断服务端是否通过了验证 if (userDAO.isLoginOK(phoneNumber, passWord)) { out.println("OK"); }else { out.println("Wrong"); } out.flush(); out.close(); } }安卓客户端（安卓我不太懂，如有错误，欢迎斧正） 布局：activity_main.xml AndroidManifest.xml,这里需要加 和android:usesCleartextTraffic="true"，至于原因在下面说明了，否则会出现异常。
HttpCallbackListener.java，这个接口会在下面以匿名内部类的方式实现其业务逻辑 package com.example.asus.httpcallbacklistener; //请求回调接口 public interface HttpCallbackListener { void onFinish(String response); void onError(Exception e); }HttpUtil,使用http请求和java服务端连接的工具类 package com.example.asus.httpcallbacklistener; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLEncoder; import java.util.HashMap; import java.util.Map; /** * 发送http的工具类 */ public class HttpUtil { //封装的发送请求函数 public static void sendHttpRequest(final String address, final HttpCallbackListener listener) { if (!HttpUtil.isNetworkAvailable()){ //这里写相应的网络设置处理 return; } new Thread(new Runnable() { @Override public void run() { HttpURLConnection connection = null; try{ URL url = new URL(address); //使用HttpURLConnection connection = (HttpURLConnection) url.openConnection(); //设置方法和参数 //请求方法 connection.setRequestMethod("GET"); //连接超时时间 connection.setConnectTimeout(8000); //读取超时异常 connection.setReadTimeout(8000); connection.setDoInput(true); connection.setDoOutput(true); //获取返回结果 InputStream inputStream = connection.getInputStream(); BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream)); StringBuilder response = new StringBuilder(); String line; while ((line = reader.readLine()) != null){ response.append(line); } //成功则回调onFinish if (listener != null){ listener.onFinish(response.toString()); } } catch (Exception e) { e.printStackTrace(); //出现异常则回调onError if (listener != null){ listener.onError(e); } }finally { if (connection != null){ connection.disconnect(); } } } }).start(); } //组装出带参数的完整URL public static String getURLWithParams(String address,HashMap params) throws UnsupportedEncodingException { //设置编码 final String encode = "UTF-8"; StringBuilder url = new StringBuilder(address); url.append("?"); //将map中的key，value构造进入URL中 for(Map.Entry entry:params.entrySet()) { url.append(entry.getKey()).append("="); url.append(URLEncoder.encode(entry.getValue(), encode)); url.append("&"); } //删掉最后一个& url.deleteCharAt(url.length() - 1); return url.toString(); //结果大致为http://192.168.3.1:8080/loginServlet"?phone=123456&password=abc123456 } //判断当前网络是否可用 public static boolean isNetworkAvailable(){ //这里检查网络，后续再添加 return true; } }
MainActivity.java，在这里一定要注意自己的ip地址，如果是本机上调试，需要改为局域网上的ip地址，如果上线的话，应该是要用外网的方式吧 package com.example.asus.httpcallbacklistener; import android.os.Handler; import android.os.Message; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.Toolbar; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; import java.util.HashMap; public class MainActivity extends AppCompatActivity implements View.OnClickListener{ private EditText mPhoneNumberEditText; private EditText mPassWordEditText; private Button mLoginButton; //用于接收Http请求的servlet的URL地址，请自己定义,这里的ip地址为局域网地址 // 这里不能使用例如：http://localhost:8080/loginServlet这样的本地访问url， //因为虚拟机上访问的本地ip为虚拟机上的，和这个电脑服务器上的ip不太一样，当然 //应该也可以用外网ip. private String originAddress = "http://192.168.3.1:8080/loginServlet"; //用于处理消息的Handler Handler mHandler = new Handler(){ @Override public void handleMessage(Message msg) { super.handleMessage(msg); String result = ""; if ("OK".equals(msg.obj.toString())){ result = "success"; }else if ("Wrong".equals(msg.obj.toString())){ result = "fail"; }else { result = msg.obj.toString(); } Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT).show(); } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); initEvent(); } private void initView() { /* Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); setSupportActionBar(toolbar);*/ mPhoneNumberEditText = (EditText) findViewById(R.id.phoneNumberEditText); mPassWordEditText = (EditText) findViewById(R.id.passwordEditText); mLoginButton = (Button) findViewById(R.id.loginButton); } private void initEvent() { mLoginButton.setOnClickListener(this); } public void login() { //检查用户输入的账号和密码的合法性 if (!isInputValid()){ return; } //构造HashMap HashMap params = new HashMap(); params.put(User.PHONENUMBER, mPhoneNumberEditText.getText().toString()); params.put(User.PASSWORD, mPassWordEditText.getText().toString()); try { //构造完整URL String compeletedURL = HttpUtil.getURLWithParams(originAddress, params); //发送请求 HttpUtil.sendHttpRequest(compeletedURL, new HttpCallbackListener() { @Override public void onFinish(String response) { Message message = new Message(); message.obj = response; mHandler.sendMessage(message); } @Override public void onError(Exception e) { Message message = new Message(); message.obj = e.toString(); mHandler.sendMessage(message); } }); } catch (Exception e) { e.printStackTrace(); } } private boolean isInputValid() { //检查用户输入的合法性，这里暂且默认用户输入合法,如果要进行后端校验，可以在这里进行业务逻辑处理 return true; } @Override public void onClick(View v) { switch (v.getId()){ case R.id.loginButton: login(); break; } } }
User.java，这是安卓端的User类，用于封装数据。 package com.example.asus.httpcallbacklistener; import java.io.Serializable; import java.util.Date; public class User implements Serializable { private int id; private String phoneNumber; private String password; private String userName; private String emailAddress; private Date registerTime; //用于URL传参和取参时的key public static String PHONENUMBER = "phoneNumber"; public static String PASSWORD = "passWord"; public static String USERNAME = "userName"; //构造函数 public User(String phoneNumber,String password,String userName){ this.phoneNumber = phoneNumber; this.password = password; this.userName = userName; registerTime = new Date(); } //属性的get与set方法不再贴出 public int getId() { return id; } public void setId(int id) { this.id = id; } public String getPhoneNumber() { return phoneNumber; } public void setPhoneNumber(String phoneNumber) { this.phoneNumber = phoneNumber; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getEmailAddress() { return emailAddress; } public void setEmailAddress(String emailAddress) { this.emailAddress = emailAddress; } public Date getRegisterTime() { return registerTime; } public void setRegisterTime(Date registerTime) { this.registerTime = registerTime; } public static String getPHONENUMBER() { return PHONENUMBER; } public static void setPHONENUMBER(String PHONENUMBER) { User.PHONENUMBER = PHONENUMBER; } public static String getPASSWORD() { return PASSWORD; } public static void setPASSWORD(String PASSWORD) { User.PASSWORD = PASSWORD; } public static String getUSERNAME() { return USERNAME; } public static void setUSERNAME(String USERNAME) { User.USERNAME = USERNAME; } }
最终：效果图
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