尝试使用输入流和错误流的资源

Question

当涉及到getInputStream 和getErrorStream 时，我如何使用try with resource 来覆盖所有角落

HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
BufferedReader bufferedReader;
if(connection.getResponseCode() == 200) {
    bufferedReader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
} else {
    bufferedReader = new BufferedReader(new InputStreamReader(connection.getErrorStream()));
}

String line;
StringBuilder result = new StringBuilder();
while((line = bufferedReader.readLine()) != null) {result.append(line);}
bufferedReader.close();

if(connection.getResponseCode() != 200) {
    throw new Gson().fromJson(result.toString(), FooException.class);
} else {
    return new Gson().fromJson(result.toString(), Foo.class);
}

Answer 1

如果我理解您的问题，那么您可以使用三元运算符? : 在try-with-resources 中构造您的BufferedReader。另外，我会将responseCode 保存到局部变量中。比如，

StringBuilder result = new StringBuilder();
int responseCode = connection.getResponseCode();
try (BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(
        responseCode == 200 ? connection.getInputStream() 
        : connection.getErrorStream()))) {
    String line;
    while ((line = bufferedReader.readLine()) != null) {
        result.append(line);
    }
}
if (responseCode != 200) {
    throw new Gson().fromJson(result.toString(), FooException.class);
} else {
    return new Gson().fromJson(result.toString(), Foo.class);
}