【Android】使用网络技能——WebView的用法、http协议、OKHttp、解析XML、J
WebView的用法新建一个WebView项目
修改activity_main中的代码：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/main"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<WebView
android:id="@+id/web_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
我们在结构文件中用到了新的控件：WebView，用来表现网页
下来修改MainActivity中的代码：
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
WebView webView = (WebView) findViewById(R.id.web_view);
webView.getSettings().setJavaScriptEnabled(true);
webView.setWebChromeClient(new WebChromeClient());
webView.loadUrl("https://www.csdn.net/");
}
}
末了到场网络申请权限就可以了：
<uses-permission android:name="android.permission.INTERNET"/>
使用http协议：
新建NetworkTest项目
修改activity_main中的代码：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/main"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Button
android:id="@+id/send_request"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Send Request"/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="@+id/request_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</ScrollView>
</LinearLayout>
修改MainActivity中的代码：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
// 用于显示HTTP请求结果的TextView
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 获取发送请求按钮的引用
Button sendRequest = (Button) findViewById(R.id.send_request);
// 获取显示响应结果的TextView的引用
responseText = (TextView) findViewById(R.id.request_text);
// 为按钮设置点击监听器
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
// 检查点击事件是否来自发送请求按钮
if (v.getId() == R.id.send_request) {
// 发送HTTP请求
sendRequestWithHttpURLConnection();
}
}
// 使用HttpURLConnection发送HTTP请求
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
// 创建URL对象
URL url = new URL("https://www.csdn.net/");
// 打开HttpURLConnection
connection = (HttpURLConnection) url.openConnection();
// 设置请求方法为GET
connection.setRequestMethod("GET");
// 设置连接超时时间和读取超时时间
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
// 获取服务器响应的输入流
InputStream in = connection.getInputStream();
// 使用BufferedReader读取输入流
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
// 显示服务器响应
showResponse(response.toString());
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭BufferedReader
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
// 断开HttpURLConnection连接
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
// 在UI线程上显示服务器响应
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
末了还需要申请一下网络权限：
<uses-permission android:name="android.permission.INTERNET"/>
假如想要提交数据给服务器可以举行如下修改：
connection.setRequestMethod("POST");
DataOutputStream out = new DataOutputStream(connection.getOutputStream());
out.writeBytes("username=admin&password=123456");
注意每条数据都要以键值对的情势存在，数据与数据之间用 & 分隔开
使用OKHttp
修改MainActivity中的代码：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
// 用于显示网络请求响应的TextView
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 绑定按钮和TextView
Button sendRequest = (Button) findViewById(R.id.send_request);
responseText = (TextView) findViewById(R.id.request_text);
// 为按钮设置点击监听器
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
// 使用OkHttp发送网络请求
sendRequestWithOkHttp();
}
}
// 使用OkHttp发送网络请求的方法
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://www.csdn.net/")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
showResponse(responseData);
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
// 使用HttpURLConnection发送网络请求的方法
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("https://www.csdn.net/");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (Exception e) {
e.printStackTrace();
} finally {
// 关闭资源
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
// 在UI线程中显示网络请求的响应数据
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
解析XML格式数据
先下载Apache服务器Welcome! - The Apache HTTP Server Project
下载安装后在根目录下的htdocs目录下，新建名为get_data.xml文件：
<apps>
<app>
<id>1</id>
<name>Google Maps</name>
<version>1.0</version>
</app>
<app>
<id>2</id>
<name>Chrome</name>
<version>2.1</version>
</app>
<app>
<id>3</id>
<name>Google Play</name>
<version>2.3</version>
</app>
</apps>
访问的内容为：
https://img-blog.csdnimg.cn/img_convert/b1037f43ddbc8090267fef771419d3c0.png
Pull解析
修改MainActivity中的代码：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sendRequest = (Button) findViewById(R.id.send_request);
responseText = (TextView) findViewById(R.id.request_text);
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
sendRequestWithOkHttp();
}
}
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("https://10.0.2.2/get_data.xml")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
parseXmlWithPull(responseData);
} catch (Exception e) {
e.printStackTrace();
}
}
}).start();
}
private void parseXmlWithPull(String xmlData) {
try {
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
xmlPullParser.setInput(new StringReader(xmlData));
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT) {
String nodeName = xmlPullParser.getName();
switch (eventType) {
case XmlPullParser.START_TAG:
if ("id".equals(nodeName)) {
id = xmlPullParser.nextText();
} else if ("name".equals(nodeName)) {
name = xmlPullParser.nextText();
} else if ("version".equals(nodeName)) {
version = xmlPullParser.nextText();
}
break;
case XmlPullParser.END_TAG:
if ("app".equals(nodeName)) {
Log.d("MainActivity", "id is " + id);
Log.d("MainActivity", "name is " + name);
Log.d("MainActivity", "version is " + version);
}
break;
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
e.printStackTrace();
}
}
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("https://www.csdn.net/");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (Exception e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
但是开始运行后我们并没有乐成解析数据
本人碰到的题目是网络安全策略的限制被克制。默认情况下，从Android 9（API级别28）开始，应用程序不允许举行明文HTTP流量，以是需要修改应用的网络安全配置来允许明文流量。
创建网络安全配置文件：
在res/xml目录下创建一个名为network_security_config.xml的文件，并添加以下内容：
<?xml version="1.0" encoding="utf-8"?>
<network-security-config>
<domain-config cleartextTrafficPermitted="true">
<domain includeSubdomains="true">192.168.1.75</domain> <!-- 替换为您的局域网IP地址 -->
</domain-config>
</network-security-config>
引用网络安全配置文件
AndroidManifest.xml中引用这个网络安全配置文件：
<application
android:networkSecurityConfig="@xml/network_security_config"
...>
...
</application>
修改MainActivity：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final String TAG = "MainActivity";
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sendRequest = findViewById(R.id.send_request);
responseText = findViewById(R.id.request_text);
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
sendRequestWithOkHttp();
}
}
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
// 使用电脑的局域网IP地址
Request request = new Request.Builder()
.url("http://192.168.1.75/get_data.xml")
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
Log.d(TAG, "Response data: " + responseData);
parseXmlWithPull(responseData);
} catch (Exception e) {
Log.e(TAG, "Request failed", e);
}
}
}).start();
}
private void parseXmlWithPull(String xmlData) {
try {
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
xmlPullParser.setInput(new StringReader(xmlData));
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT) {
String nodeName = xmlPullParser.getName();
switch (eventType) {
case XmlPullParser.START_TAG:
if ("id".equals(nodeName)) {
id = xmlPullParser.nextText();
} else if ("name".equals(nodeName)) {
name = xmlPullParser.nextText();
} else if ("version".equals(nodeName)) {
version = xmlPullParser.nextText();
}
break;
case XmlPullParser.END_TAG:
if ("app".equals(nodeName)) {
Log.i(TAG, "id is " + id);
Log.i(TAG, "name is " + name);
Log.i(TAG, "version is " + version);
}
break;
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
Log.e(TAG, "XML parsing failed", e);
}
}
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("http://192.168.1.75/get_data.xml");
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (Exception e) {
Log.e(TAG, "Request failed", e);
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
解析JSON格式数据
相比于XML，JSON的重要上风在于它的体积更小，在网络传输时可以更省流量
但是缺点在于它的语义性较差
起首在Apache目录下的htdocs目录中新建一个get_data.json文件，到场以下内容：
[{"id":"5","version":"5.5","name":"Clash of Clans"},
{"id":"6","version":"7.0","name":"Boom Beach"},
{"id":"7","version":"3.5","name":"Clash Royale"}]
在浏览器打开为：
https://img-blog.csdnimg.cn/img_convert/ca06b471209026920b6d689b3eaf7b8a.png
下面就可以开始解析数据了：
使用JSONObject
修改MainActivity中的代码：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final String TAG = "MainActivity";
TextView responseText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button sendRequest = findViewById(R.id.send_request);
responseText = findViewById(R.id.request_text);
sendRequest.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) {
sendRequestWithOkHttp();
}
}
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.1.75/get_data.json") // 确认返回的是JSON数据
.build();
Response response = client.newCall(request).execute();
String responseData = response.body().string();
Log.d(TAG, "Response Data: " + responseData);
parseJSONWithJSONObject(responseData);
} catch (Exception e) {
Log.e(TAG, "Request failed", e);
}
}
}).start();
}
private void parseJSONWithJSONObject(String jsonData) {
try {
JSONArray jsonArray = new JSONArray(jsonData);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String id = jsonObject.getString("id");
String name = jsonObject.getString("name");
String version = jsonObject.getString("version");
Log.d(TAG, "id is " + id);
Log.d(TAG, "name is " + name);
Log.d(TAG, "version is " + version);
}
} catch (JSONException e) {
Log.e(TAG, "JSON parsing failed", e);
}
}
private void parseXmlWithPull(String xmlData) {
try {
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
xmlPullParser.setInput(new StringReader(xmlData));
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT) {
String nodeName = xmlPullParser.getName();
switch (eventType) {
case XmlPullParser.START_TAG:
if ("id".equals(nodeName)) {
id = xmlPullParser.nextText();
} else if ("name".equals(nodeName)) {
name = xmlPullParser.nextText();
} else if ("version".equals(nodeName)) {
version = xmlPullParser.nextText();
}
break;
case XmlPullParser.END_TAG:
if ("app".equals(nodeName)) {
Log.i(TAG, "id is " + id);
Log.i(TAG, "name is " + name);
Log.i(TAG, "version is " + version);
}
break;
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
Log.e(TAG, "XML parsing failed", e);
}
}
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("http://192.168.1.75/get_data.json"); // 确认返回的是JSON数据
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString());
} catch (Exception e) {
Log.e(TAG, "Request failed", e);
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
使用GSON
要想使用GSON，起首需要添加依赖库：
implementation("com.google.code.gson:gson:2.7")
新建App类：
package com.example.networktest;
public class App {
private String id;
private String name;
private String version;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getVersion() {
return version;
}
public void setVersion(String version) {
this.version = version;
}
}
修改MainActivity中的代码：
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final String TAG = "MainActivity"; // 日志标签
TextView responseText; // 用于显示响应数据的TextView
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); // 设置活动布局
Button sendRequest = findViewById(R.id.send_request); // 获取发送请求按钮
responseText = findViewById(R.id.request_text); // 获取用于显示响应的TextView
sendRequest.setOnClickListener(this); // 为按钮设置点击事件监听器
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.send_request) { // 检查点击的视图ID是否为发送请求按钮
sendRequestWithOkHttp(); // 调用方法发送HTTP请求
}
}
// 使用OkHttp发送HTTP请求
private void sendRequestWithOkHttp() {
new Thread(new Runnable() {
@Override
public void run() {
try {
OkHttpClient client = new OkHttpClient();
Request request = new Request.Builder()
.url("http://192.168.1.75/get_data.json") // 请求URL
.build();
Response response = client.newCall(request).execute(); // 执行请求
String responseData = response.body().string(); // 获取响应数据
parseJSONWithGSON(responseData); // 解析JSON数据
} catch (Exception e) {
Log.e(TAG, "Request failed", e); // 记录请求失败的日志
}
}
}).start();
}
// 使用GSON解析JSON数据
private void parseJSONWithGSON(String jsonData) {
Gson gson = new Gson();
List<App> appList = gson.fromJson(jsonData, new TypeToken<List<App>>(){}.getType()); // 将JSON数据转换为App对象列表
for (App app : appList) {
Log.d("MainActivity", "id is " + app.getId());
Log.d("MainActivity", "name is " + app.getName());
Log.d("MainActivity", "version is " + app.getVersion());
}
}
// 使用JSONObject解析JSON数据
private void parseJSONWithJSONObject(String jsonData) {
try {
JSONArray jsonArray = new JSONArray(jsonData); // 创建JSON数组
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
String id = jsonObject.getString("id");
String name = jsonObject.getString("name");
String version = jsonObject.getString("version");
Log.d(TAG, "id is " + id);
Log.d(TAG, "name is " + name);
Log.d(TAG, "version is " + version);
}
} catch (JSONException e) {
Log.e(TAG, "JSON parsing failed", e); // 记录JSON解析失败的日志
}
}
// 使用Pull解析XML数据
private void parseXmlWithPull(String xmlData) {
try {
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
XmlPullParser xmlPullParser = factory.newPullParser();
xmlPullParser.setInput(new StringReader(xmlData));
int eventType = xmlPullParser.getEventType();
String id = "";
String name = "";
String version = "";
while (eventType != XmlPullParser.END_DOCUMENT) {
String nodeName = xmlPullParser.getName();
switch (eventType) {
case XmlPullParser.START_TAG:
if ("id".equals(nodeName)) {
id = xmlPullParser.nextText();
} else if ("name".equals(nodeName)) {
name = xmlPullParser.nextText();
} else if ("version".equals(nodeName)) {
version = xmlPullParser.nextText();
}
break;
case XmlPullParser.END_TAG:
if ("app".equals(nodeName)) {
Log.i(TAG, "id is " + id);
Log.i(TAG, "name is " + name);
Log.i(TAG, "version is " + version);
}
break;
default:
break;
}
eventType = xmlPullParser.next();
}
} catch (Exception e) {
Log.e(TAG, "XML parsing failed", e); // 记录XML解析失败的日志
}
}
// 使用HttpURLConnection发送HTTP请求
private void sendRequestWithHttpURLConnection() {
new Thread(new Runnable() {
@Override
public void run() {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL("http://192.168.1.75/get_data.json"); // 请求URL
connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setConnectTimeout(8000);
connection.setReadTimeout(8000);
InputStream in = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder response = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
response.append(line);
}
showResponse(response.toString()); // 显示响应数据
} catch (Exception e) {
Log.e(TAG, "Request failed", e); // 记录请求失败的日志
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (connection != null) {
connection.disconnect();
}
}
}
}).start();
}
// 在主线程上显示响应数据
private void showResponse(final String response) {
runOnUiThread(new Runnable() {
@Override
public void run() {
responseText.setText(response);
}
});
}
}
打印结果如图所示：
https://img-blog.csdnimg.cn/img_convert/e4ed37b054bbb8f595c1e0827a7a2cb1.png
已经到底啦！！
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