Java 获取HTTP Url连接中的错误
我正在为我的学校编写一个应用程序,我想展示网站上的新闻,所以我必须在我的应用程序中获取源代码。这是我从网站获取Html源代码的代码:Java 获取HTTP Url连接中的错误,java,http,url,client,Java,Http,Url,Client,我正在为我的学校编写一个应用程序,我想展示网站上的新闻,所以我必须在我的应用程序中获取源代码。这是我从网站获取Html源代码的代码: public String getHTML(String urlToRead) { URL url; HttpURLConnection conn; BufferedReader rd; String line; String result = ""; try { url = new URL(urlT
public String getHTML(String urlToRead) {
URL url;
HttpURLConnection conn;
BufferedReader rd;
String line;
String result = "";
try {
url = new URL(urlToRead);
conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
while ((line = rd.readLine()) != null) {
result += line;
}
rd.close();
} catch (Exception e) {
result += e.toString();
}
return result;
}
如果我有互联网连接,它可以正常工作,但如果没有连接,应用程序就会崩溃。如果没有连接到Internet,如何在应用程序中显示错误而不使其崩溃?
(对不起我的英语,我是来自德国的学生…)
有人能帮我吗
谢谢
Jonathan你需要抓住未知的后异常: 此外,我还将更改您的方法,使其仅从连接返回InputStream,并处理与之相关的所有异常。然后尝试读取或解析它,或者用它做任何其他事情。您可以获取errorInputStream并将对象状态更改为error(如果有)。你可以用同样的方法解析它,只需要做不同的逻辑 我想要更像:
public class TestHTTPConnection {
boolean error = false;
public InputStream getContent(URL urlToRead) throws IOException {
InputStream result = null;
error = false;
HttpURLConnection conn = (HttpURLConnection) urlToRead.openConnection();
try {
conn.setRequestMethod("GET");
result = conn.getInputStream();
} catch (UnknownHostException e) {
error = true;
result = null;
System.out.println("Check Internet Connection!!!");
} catch (Exception ex) {
ex.printStackTrace();
error = true;
result = conn.getErrorStream();
}
return result;
}
public boolean isError() {
return error;
}
public static void main(String[] args) {
TestHTTPConnection test = new TestHTTPConnection();
InputStream inputStream = null;
try {
inputStream = test.getContent(new URL("https://news.google.com/"));
if (inputStream != null) {
BufferedReader rd = new BufferedReader(new InputStreamReader(
inputStream));
StringBuilder data = new StringBuilder();
String line;
while ((line = rd.readLine()) != null) {
data.append(line);
data.append('\n');
}
System.out.println(data);
rd.close();
}
} catch (MalformedURLException e) {
System.out.println("Check URL!!!");
} catch (IOException e) {
e.printStackTrace();
}
}
}
我希望它能帮助你,祝你的项目好运。你需要抓住未知的例外: 此外,我还将更改您的方法,使其仅从连接返回InputStream,并处理与之相关的所有异常。然后尝试读取或解析它,或者用它做任何其他事情。您可以获取errorInputStream并将对象状态更改为error(如果有)。你可以用同样的方法解析它,只需要做不同的逻辑 我想要更像:
public class TestHTTPConnection {
boolean error = false;
public InputStream getContent(URL urlToRead) throws IOException {
InputStream result = null;
error = false;
HttpURLConnection conn = (HttpURLConnection) urlToRead.openConnection();
try {
conn.setRequestMethod("GET");
result = conn.getInputStream();
} catch (UnknownHostException e) {
error = true;
result = null;
System.out.println("Check Internet Connection!!!");
} catch (Exception ex) {
ex.printStackTrace();
error = true;
result = conn.getErrorStream();
}
return result;
}
public boolean isError() {
return error;
}
public static void main(String[] args) {
TestHTTPConnection test = new TestHTTPConnection();
InputStream inputStream = null;
try {
inputStream = test.getContent(new URL("https://news.google.com/"));
if (inputStream != null) {
BufferedReader rd = new BufferedReader(new InputStreamReader(
inputStream));
StringBuilder data = new StringBuilder();
String line;
while ((line = rd.readLine()) != null) {
data.append(line);
data.append('\n');
}
System.out.println(data);
rd.close();
}
} catch (MalformedURLException e) {
System.out.println("Check URL!!!");
} catch (IOException e) {
e.printStackTrace();
}
}
}
我希望它能帮助你,祝你的项目好运