servlet连接数据库显示到android界面qq45111873的博客-

数据库—servlet—android

android是不能直接访问数据库的，所以可以通过servlet来访问数据库显示到android界面。通常如果你的电脑运行内存还行的话，就用两个eclipse，我就用了两个eclipse，一个用于servlet连接数据库，就是有web项目的eclipse，另一个是用于android的，就是得有SDK和ADT的android项目。
先讲第一个，也就是数据库-servlet

这是数据库的设计建表
包括一个输入校验表和一个界面主表显示



第一部分代码,也就是第一个有动态web的eclipse中的代码（由于代码较多，其他的都放在了我的网盘里，网盘放的就是我的整个项目）
链接：https://pan.baidu.com/s/1Xw2O2-C5UMIcRjNaNibBCg 提取码：jzw8
现在我展示的是servlet连接数据库的代码
responseJsonData.java

package com.bai; import java.io.IOException; import java.io.PrintWriter; import java.net.URLEncoder; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; 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 com.alibaba.fastjson.JSON; import com.alibaba.fastjson.JSONObject; /**  * Servlet implementation class responseJsonData  */ @WebServlet("/responseJsonData") public class responseJsonData extends HttpServlet { private static final long serialVersionUID = 1L; /**      * @see HttpServlet#HttpServlet()      */ public responseJsonData() { super(); // TODO Auto-generated constructor stub } /**   * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)   */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doPost( request,  response); } /**   * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)   */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub    Connection con;   Statement sql;   ResultSet rs;   PrintWriter out =response.getWriter(); try{Class.forName("com.mysql.cj.jdbc.Driver").newInstance();} catch(Exception e){out.print(e);} try{       String uri="jdbc:mysql://localhost:3306/android?useSSL=false&serverTimezone=UTC";       con=DriverManager.getConnection(uri,"root","199735");       sql=con.createStatement();       rs=sql.executeQuery("SELECT * FROM student");            ArrayList<student> arrList = new ArrayList<student>(); while(rs.next()) {        student s = new student();        s.setSno(rs.getString("sno"));        s.setSname(rs.getString("sname"));        s.setSage(rs.getString("sage"));        s.setSbirth(rs.getDate("sbirth").toString());        arrList.add(s); }        String  js1 = JSONObject.toJSONString(arrList);       System.out.println(js1);       response.setContentType("text/html; charset=utf-8");       response.setCharacterEncoding("utf-8");       out.print(js1);              con.close(); } catch(SQLException e1){out.print(e1);} } } 

在eclipse里运行，这里面有默认的浏览器，服务器Tomcat也加进去了，就直接运行了

这样，就通过servlet访问连接到了数据库

第二部分，servlet-android

android项目代码，我在这儿展示的是连接访问servlet的代码，其他代码可以去看我网盘:（整个项目在网盘：链接：https://pan.baidu.com/s/1qFMYx7NXWQvrtnvnvhfafA 提取码：kemv）
RegisterAct.java,这个用于连接loginservlet，进行输入校验

package com.example.testjson; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.params.BasicHttpParams; import org.apache.http.params.HttpConnectionParams; import org.apache.http.params.HttpParams; import org.apache.http.protocol.HTTP; import org.json.JSONArray; import org.json.JSONObject; import com.example.testjson.MainActivity.DownloadThread; import android.app.Activity; import android.app.AlertDialog; import android.app.AlertDialog.Builder; import android.content.DialogInterface; import android.content.Intent; import android.content.DialogInterface.OnClickListener; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.SimpleAdapter; import android.widget.Toast; public class RegisterAct extends Activity { private Button reset; private Button register; // 用户 private EditText uNameEditText; // 密码 private EditText pwdEditText1; private String userName; private String password; private String serverIp = "10.0.2.2"; private String serverPort = "8080"; private String httpStr; private String postStr; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.register);   reset = (Button) findViewById(R.id.reset);   register = (Button) findViewById(R.id.register);   uNameEditText=(EditText)findViewById(R.id.username);   pwdEditText1=(EditText)findViewById(R.id.password1);   register.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if (registerIsSuccsee()) { //register();      LoginThread loginThread = new LoginThread();      loginThread.start(); } } });   reset.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) {      uNameEditText.setText("");     pwdEditText1.setText(""); } }); } /*   * 判断用户注册输入是否规范 录入信息验证 验证是否通过   */ private boolean registerIsSuccsee(){ //获取用户输入      userName=uNameEditText.getText().toString();      password=pwdEditText1.getText().toString(); if("".equals(userName)){ //用户输入用户名为空       Toast.makeText(RegisterAct.this, "用户名不能为空!", Toast.LENGTH_SHORT).show(); return false; }else if("".equals(password)){ //密码不能为空       Toast.makeText(RegisterAct.this, "密码不能为空!", Toast.LENGTH_SHORT).show(); return false; } return true; } class LoginThread extends Thread{ @Override public void run() { register(); } } /**   * 注册   */ private void register() {      httpStr = "https://";   postStr = httpStr + serverIp + ":" + serverPort     + "/aaaa/loginServlet"; try {    HttpParams httpParams = new BasicHttpParams(); // 设置连接超时 int timeoutConnection = 3000;    HttpConnectionParams.setConnectionTimeout(httpParams,      timeoutConnection);    DefaultHttpClient httpClient = new DefaultHttpClient(httpParams);    HttpPost httpPost = new HttpPost(postStr);    List<NameValuePair> nvps = new ArrayList<NameValuePair>();    nvps.add(new BasicNameValuePair("username", userName));    nvps.add(new BasicNameValuePair("password", password));    nvps.add(new BasicNameValuePair("client", "1"));    httpPost.setEntity(new UrlEncodedFormEntity(nvps, HTTP.UTF_8));    HttpResponse response = httpClient.execute(httpPost);    HttpEntity entity = response.getEntity();    InputStream is=entity.getContent();    String isUser = ConvertStreamToString(is);     Message msg = new Message();              msg.what = 3; if(!"failure".equals(isUser)){           msg.what = 1; }else{           msg.what = 2; }    uiHandler.sendMessage(msg); /*if(!"failure".equals(isUser)){          //uNameEditText.setText("");     //pwdEditText1.setText("");     Intent i=new Intent(RegisterAct.this,MainActivity.class);     startActivity(i);    }else{          AlertDialog.Builder builder1=new Builder(RegisterAct.this);     builder1.setMessage("用户名或密码不正确！！！");     builder1.setTitle("提示");     builder1.setPositiveButton("确认", new OnClickListener() {            @Override      public void onClick(DialogInterface dialog, int which) {       dialog.dismiss();      }     }).show();    }*/ } catch (UnsupportedEncodingException e) {    e.printStackTrace(); } catch (ClientProtocolException e) {    e.printStackTrace(); } catch (IOException e) {    e.printStackTrace(); } } private Handler uiHandler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what){ case 1:                  uNameEditText.setText("");         pwdEditText1.setText("");         Intent i=new Intent(RegisterAct.this,MainActivity.class); startActivity(i); break; case 2:                   AlertDialog.Builder builder1=new Builder(RegisterAct.this);         builder1.setMessage("用户名或密码不正确！！！");         builder1.setTitle("提示");         builder1.setPositiveButton("确认", new OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) {           dialog.dismiss(); } }).show(); break; default: break; } } }; // 读取字符 public String ConvertStreamToString(InputStream is) {   StringBuffer sb = new StringBuffer();   BufferedReader br = new BufferedReader(new InputStreamReader(is));   String returnStr = ""; try { while ((returnStr = br.readLine()) != null) {     sb.append(returnStr); } } catch (IOException e) {    e.printStackTrace(); } final String result = sb.toString();    System.out.println(result); return result; } } 

MainActivity.java,这个用于连接访问responseJsonData,进行android界面显示

package com.example.testjson; import android.app.Activity; import android.os.Bundle; import android.util.Log; import android.view.Menu; import android.view.MenuItem; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.Serializable; import java.net.URLDecoder; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; 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 org.json.JSONArray; import org.json.JSONObject; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.app.Activity; import android.content.Intent; import android.view.Menu; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ListView; import android.widget.SimpleAdapter; public class MainActivity extends Activity { private ListView lv; // uiHandler在主线程中创建，所以自动绑定主线程 // private Handler uiHandler = new Handler(); //uiHandler在主线程中创建，所以自动绑定主线程 private Handler uiHandler = new Handler(){ @Override public void handleMessage(Message msg) { switch (msg.what){ case 1:                     System.out.println("handleMessage thread id " + Thread.currentThread().getId());                     System.out.println("msg.arg1:" + msg.arg1); int[] i = new int[] { R.id.name, R.id.jing, R.id.wei };            SimpleAdapter simplead = new SimpleAdapter(MainActivity.this, (List)msg.obj, R.layout.show, new String[] { "name", "jing", "wei" }, i);            MainActivity.this.lv.setAdapter(simplead); break; } } }; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main);   lv = (ListView) findViewById(R.id.listView1);    DownloadThread downloadThread = new DownloadThread();         downloadThread.start(); } class DownloadThread extends Thread{ @Override public void run() {       List<Map<String, Object>> listall = new ArrayList<Map<String, Object>>();       StringBuilder builder = new StringBuilder();       HttpClient client = new DefaultHttpClient();       HttpGet get = new HttpGet( "https://10.0.2.2:8080/aaaa/responseJsonData"); try {        HttpResponse response = client.execute(get);               BufferedReader reader = new BufferedReader( new InputStreamReader(response.getEntity().getContent(),"GBK")); for (String s = reader.readLine(); s != null; s = reader          .readLine()) {         builder.append(s); }        reader.close();        String str = builder.toString();        Log.d("json",str); //str.getBytes("utf-8");        JSONArray array = new JSONArray(new String(str));        Map<String, Object> listem1 = new HashMap<String, Object>();     listem1.put("name", "学号");     listem1.put("jing", "姓名");     listem1.put("wei", "专业");     listall.add(listem1); for (int i = 0; i < array.length(); i++) {         JSONObject item = array.getJSONObject(i);         String name = item.getString("sno");         String u_longitude = item.getString("sname");               String u_latitude = item.getString("sage");         Map<String, Object> listem = new HashMap<String, Object>();         listem.put("name", name);         listem.put("jing", u_longitude);         listem.put("wei", u_latitude);         listall.add(listem); }         Message msg = new Message();                 msg.what = 1;                 msg.obj = listall; //将该Message发送给对应的Handler                 uiHandler.sendMessage(msg); } catch (Exception e) {        e.printStackTrace(); } } } } 

运行进入登录界面，输入用户名和密码

最后，就显示出来了

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