android端获取Tomcat服务器端json数据并通过listview显示

发表于 | 分类于
字数统计: 2k word | 阅读时长 ≈ 11 min
大体描述：

大体意思是用eclipse ee创建一个Javaweb项目,该项目能从MySQL数据库中获取user表的数据，将数据封装成json格式，将此项目发布到本地Tomcat服务器，在android端获取刚才的json数据，并用listview显示。废话不多说下面直接开始。

Tomcat服务器端

很简单，建立一个servlet用来处理数据，再建一个数据库工具类，我这里是DatabaseUtil.java，不要忘记servlet在web.xml中需要注册。

项目结构：

code:
ServletDemo1.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
package com.servlet.demo;

import java.io.IOException;
import java.sql.ResultSet;
import java.sql.SQLException;
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 net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import util.DatabaseUtil;

public class ServletDemo1 extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public ServletDemo1() {
		super();
	}

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String sql = "select * from user";
		JSONArray jsonArray=new JSONArray(); //json数组
		try {
			ResultSet result = DatabaseUtil.query(sql);
			while (result.next()) {
				JSONObject jObject=new JSONObject();  //json临时对象
				jObject.put("id", result.getInt(1));
				jObject.put("username", result.getString(2));
				jObject.put("password", result.getString(3));
				jsonArray.add(jObject);   //将封装好的json对象放入json数组
			}

		} catch (SQLException e) {
			e.printStackTrace();
		}
	    String jsondata=jsonArray.toString();  //将json数组转换成字符串，供下面返回给android端使用
		//System.out.println(jsondata);  //本地测试用
		response.getWriter().append(jsondata).flush();
	}
}
DatabaseUtil.java
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
package util;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;

import com.mysql.jdbc.Statement;

public class DatabaseUtil {

	private static Connection mConnection;

	private static Connection getConnection() {
		if (mConnection == null) {
			String url = "jdbc:mysql://localhost:3306/mybatis"; 
			try {
				Class.forName("com.mysql.jdbc.Driver"); 
				mConnection = (Connection) DriverManager.getConnection(url, "root", "123");
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		return mConnection;
	}
	//这里只用了查询操作
	public static ResultSet query(String querySql) throws SQLException {
		Statement stateMent = (Statement) getConnection().createStatement();
		return stateMent.executeQuery(querySql);
	}
	
	public static void closeConnection() {
		if (mConnection != null) {
			try {
				mConnection.close();
				mConnection = null;
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}
}
web.xml
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <display-name>ConnectTest</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
  	<servlet-name>ServletDemo1</servlet-name>
  	<servlet-class>com.servlet.demo.ServletDemo1</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>ServletDemo1</servlet-name>
  	<url-pattern>/ServletDemo1</url-pattern>
  </servlet-mapping>
</web-app>
本地测试结果

在浏览器地址栏里输入（端口啥的自己改了的话用自己的，不多说）

1
http://localhost:8080/ConnectTest/ServletDemo1

测试结果：

android端

也比较简单，有两个activity，在mainactivity中有个button按钮，点击后跳转到第二个activity,我这里是ListActivity ,在listactivity中显示获取到的json数据。

用到的jar包

类

布局

code
工具类 HttpUtil
1
2
3
4
5
6
7
8
9
10
11
12
package util;

import okhttp3.OkHttpClient;
import okhttp3.Request;

public class HttpUtil {
    public static void sendOkHttpRequest(String address,okhttp3.Callback callback){
        OkHttpClient client=new OkHttpClient();
        Request request=new Request.Builder().url(address).build();
        client.newCall(request).enqueue(callback);
    }
}
实体类 User
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
package com.ccc.connecttest.activity;

public class User {
    private int id;
    private String username;
    private String password;

    public User(int id,String username, String password){
        this.id=id;
        this.username=username;
        this.password=password;
    }
    public int getId() {
        return id;
    }

    public String getUsername() {
        return username;
    }

    public String getPassword() {
        return password;
    }
}
适配器 UserAdapter
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
package com.ccc.connecttest.activity;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import com.ccc.connecttest.R;
import java.util.List;

public class UserAdapter extends ArrayAdapter<User> {
    private int resourceId;
    public UserAdapter(Context context, int resourceId, List<User> objects) {
        super(context, resourceId,objects);
        this.resourceId=resourceId;
    }

    @Override
    public View getView(int position,  View convertView,ViewGroup parent) {
        User user=getItem(position);
        View view;
        ViewHolder viewHolder;
        if(convertView==null){
            view= LayoutInflater.from(getContext()).inflate(resourceId,parent,false);
            viewHolder=new ViewHolder();
            viewHolder.userid=(TextView)view.findViewById(R.id.tv_id);
            viewHolder.username=(TextView)view.findViewById(R.id.tv_username);
            viewHolder.userpassword=(TextView)view.findViewById(R.id.tv_password);
            view.setTag(viewHolder); //将viewHolder存储在view中
        }else{
            view=convertView;
            viewHolder=(ViewHolder)view.getTag();
        }
        viewHolder.userid.setText(String.valueOf(user.getId()));
        viewHolder.username.setText(user.getUsername());
        viewHolder.userpassword.setText(user.getPassword());
        return view;
    }

    static class ViewHolder{
        TextView userid;
        TextView username;
        TextView userpassword;
    }
}
显示的页面 ListActivity
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
package com.ccc.connecttest.activity;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.widget.ListView;
import com.ccc.connecttest.R;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Response;
import util.HttpUtil;

public class ListActivity extends AppCompatActivity {
    private List<User> userList=new ArrayList<>();
    private ListView listView;

    private String json_url="http://192.168.2.133:8080/ConnectTest/ServletDemo1";//本地Tomcat刚才测试的地址

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

        queryFromServer(json_url); //处理取得数据

        listView=findViewById(R.id.lv);
        UserAdapter adapter = new UserAdapter(ListActivity.this, R.layout.user, userList);
        listView.setAdapter(adapter);
    }

    private void queryFromServer(String json_url) {
        HttpUtil.sendOkHttpRequest(json_url, new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                Log.i("error","出现错误！");
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String responseText=response.body().string();
                try {
                    JSONArray jsonArray=new JSONArray(responseText);
                    for(int i=0;i<jsonArray.length();i++){
                        JSONObject jsonObject=jsonArray.getJSONObject(i);
                        String id=jsonObject.getString("id");
                        String username=jsonObject.getString("username");
                        String password=jsonObject.getString("password");

                        User user=new User(Integer.parseInt(id),username,password);
                        userList.add(user);

                        Log.i("user","添加了一个User");
                    }

                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }
        });
    }
}
主页面 MainActivity
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
package com.ccc.connecttest.activity;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import com.ccc.connecttest.R;

public class MainActivity extends Activity {

    private Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button=findViewById(R.id.btnSign);
		//点击跳转到显示页面
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startActivity(new Intent(MainActivity.this, ListActivity.class));
            }
        });
    }

}
配置 AndroidManifest.xml
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.ccc.connecttest">
    <!-- 千万不要忘了申请使用网络权限-->
    <uses-permission android:name="android.permission.INTERNET" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".activity.MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!-- 这个ListActivity不要忘记注册-->
        <activity android:name=".activity.ListActivity"/>
    </application>
</manifest>
布局

activity_main.xml:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
<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" >

    <Button
        android:layout_marginTop="200dp"
        android:id="@+id/btnSign"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:text="获取" />

</LinearLayout

activity_list.xml:

1
2
3
4
5
6
7
8
9
10
11
12
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    
    <ListView
        android:id="@+id/lv"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>
    
</LinearLayout>

listview每一项适配文件： user.xml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="15dp">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:id="@+id/tv_id"
            android:text="1111"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="18sp" />

        <TextView
            android:text="2222"
            android:id="@+id/tv_username"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="14sp" />

        <TextView
            android:text="3333"
            android:id="@+id/tv_password"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#d97e87"
            android:textSize="16sp" />
    </LinearLayout>
</RelativeLayout>
结果图

项目下载

点击下载

0%