import java.net.HttpURLConnection;
import java.net.URL;

public class ConnectionTimeoutExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://nonexistent.example.com:8080/api/data");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setConnectTimeout(5000); // 設(shè)置連接超時為5秒
            connection.setReadTimeout(5000);    // 設(shè)置讀取超時為5秒
            connection.setRequestMethod("GET");
            connection.connect(); // 嘗試建立連接
            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);
        } catch (java.net.ConnectException e) {
            System.err.println("Connection Error: " + e.getMessage());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import java.net.HttpURLConnection;
import java.net.URL;
import java.net.UnknownHostException;

public class UnknownHostExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("http://invalid-domain-name-xyz.com/api/data");
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            connection.connect();
            // ... 處理響應(yīng)
        } catch (UnknownHostException e) {
            System.err.println("Unknown Host Error: " + e.getMessage() + ". Please check the domain name and DNS settings.");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

// 使用OkHttp為例
import okhttp3.MediaType;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

import java.io.IOException;

public class BadRequestExample {
    public static void main(String[] args) throws IOException {
        OkHttpClient client = new OkHttpClient();
        String url = "https://api.example.com/createItem"; // 假設(shè)這是一個需要JSON的API

        // 錯誤的請求體：非JSON格式
        String wrongJson = "{name: \"Test Item\", price: 100}"; // 缺少雙引號
        MediaType JSON = MediaType.get("application/json; charset=utf-8");
        RequestBody body = RequestBody.create(wrongJson, JSON);

        Request request = new Request.Builder()
                .url(url)
                .post(body)
                .build();

        try (Response response = client.newCall(request).execute()) {
            if (!response.isSuccessful()) {
                System.err.println("HTTP Error: " + response.code() + " - " + response.message());
                System.err.println("Response Body: " + response.body().string());
            } else {
                System.out.println("Success: " + response.body().string());
            }
        }
    }
}

// 使用Spring WebClient為例
import org.springframework.web.reactive.function.client.WebClient;

public class UnauthorizedExample {
    public static void main(String[] args) {
        WebClient webClient = WebClient.create();
        String url = "https://api.example.com/secureData";
        String authToken = "your_valid_auth_token"; // 替換為實際的Token

        webClient.get()
                .uri(url)
                .header("Authorization", "Bearer " + authToken)
                .retrieve()
                .bodyToMono(String.class)
                .subscribe(response -> System.out.println("Response: " + response),
                           error -> {
                               if (error instanceof org.springframework.web.reactive.function.client.WebClientResponseException) {
                                   org.springframework.web.reactive.function.client.WebClientResponseException wcError = 
                                       (org.springframework.web.reactive.function.client.WebClientResponseException) error;
                                   System.err.println("HTTP Error: " + wcError.getStatusCode() + " - " + wcError.getStatusText());
                                   System.err.println("Response Body: " + wcError.getResponseBodyAsString());
                               } else {
                                   error.printStackTrace();
                               }
                           });

        try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); }
    }
}

// 偽代碼，展示重試邏輯
public void makeRequestWithRetry(String url, int maxRetries) {
    for (int i = 0; i < maxRetries; i++) {
        try {
            // 發(fā)送HTTP請求
            // ...
            int statusCode = response.code(); // 假設(shè)獲取狀態(tài)碼
            if (statusCode == 429) {
                long retryAfter = getRetryAfterHeader(response); // 從響應(yīng)頭獲取Retry-After
                Thread.sleep(retryAfter > 0 ? retryAfter * 1000 : (long) Math.pow(2, i) * 1000); // 指數(shù)退避
            } else if (statusCode >= 200 && statusCode < 300) {
                System.out.println("Request successful!");
                return;
            } else {
                System.err.println("Request failed with status: " + statusCode);
                return;
            }
        } catch (Exception e) {
            e.printStackTrace();
            // 可以在這里添加更復(fù)雜的錯誤處理，例如網(wǎng)絡(luò)中斷等
        }
    }
    System.err.println("Request failed after " + maxRetries + " retries.");
}

private long getRetryAfterHeader(Response response) {
    String retryAfter = response.header("Retry-After");
    if (retryAfter != null) {
        try {
            return Long.parseLong(retryAfter);
        } catch (NumberFormatException e) {
            // ignore
        }
    }
    return 0;
}

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.security.cert.X509Certificate;
import java.net.URL;

public class DisableSSLValidationExample {

    public static void main(String[] args) {
        // 創(chuàng)建一個不驗證證書鏈的TrustManager
        TrustManager[] trustAllCerts = new TrustManager[]{
            new X509TrustManager() {
                public X509Certificate[] getAcceptedIssuers() { return null; }
                public void checkClientTrusted(X509Certificate[] certs, String authType) { }
                public void checkServerTrusted(X509Certificate[] certs, String authType) { }
            }
        };

        // 創(chuàng)建一個不驗證主機(jī)名的HostnameVerifier
        HostnameVerifier allHostsValid = new HostnameVerifier() {
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        };

        try {
            SSLContext sc = SSLContext.getInstance("TLS");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
            HttpsURLConnection.setDefaultHostnameVerifier(allHostsValid);

            URL url = new URL("https://self-signed-example.com/api/data");
            HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
            connection.setRequestMethod("GET");
            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

public class UrlEncodingExample {
    public static void main(String[] args) throws UnsupportedEncodingException {
        String baseUrl = "https://api.example.com/search";
        String queryParam = "Java HTTP 請求 錯誤";
        String encodedQueryParam = URLEncoder.encode(queryParam, "UTF-8");
        String fullUrl = baseUrl + "?q=" + encodedQueryParam;
        System.out.println("Encoded URL: " + fullUrl);
        // Output: Encoded URL: https://api.example.com/search?q=Java+HTTP+%E8%AF%B7%E6%B1%82+%E9%94%99%E8%AF%AF
    }
}

// 使用Apache HttpClient為例
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.apache.http.HttpHeaders;

public class RequestHeaderExample {
    public static void main(String[] args) throws Exception {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        HttpPost httpPost = new HttpPost("https://api.example.com/data");

        // 設(shè)置Content-Type為application/json
        httpPost.setHeader(HttpHeaders.CONTENT_TYPE, "application/json");
        // 設(shè)置Accept為application/json，表示期望接收J(rèn)SON格式響應(yīng)
        httpPost.setHeader(HttpHeaders.ACCEPT, "application/json");

        String json = "{\"name\":\"test\", \"value\":123}";
        StringEntity entity = new StringEntity(json);
        httpPost.setEntity(entity);

        try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
            System.out.println("Response Status: " + response.getStatusLine());
            System.out.println("Response Body: " + EntityUtils.toString(response.getEntity()));
        }
    }
}

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class HttpURLConnectionErrorStreamExample {
    public static void main(String[] args) {
        try {
            URL url = new URL("https://jsonplaceholder.typicode.com/nonexistent"); // 假設(shè)這是一個會返回404的URL
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            int responseCode = connection.getResponseCode();
            System.out.println("Response Code: " + responseCode);

            BufferedReader reader;
            if (responseCode >= 200 && responseCode < 300) {
                reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
            } else {
                reader = new BufferedReader(new InputStreamReader(connection.getErrorStream()));
            }

            String inputLine;
            StringBuilder response = new StringBuilder();
            while ((inputLine = reader.readLine()) != null) {
                response.append(inputLine);
            }
            reader.close();
            System.out.println("Response Body: " + response.toString());

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class ApacheHttpClientCloseExample {
    public static void main(String[] args) throws Exception {
        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            HttpGet httpGet = new HttpGet("https://jsonplaceholder.typicode.com/posts/1");
            try (CloseableHttpResponse response = httpClient.execute(httpGet)) {
                System.out.println("Response Status: " + response.getStatusLine());
                System.out.println("Response Body: " + EntityUtils.toString(response.getEntity()));
            }
        }
    }
}

import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import java.io.IOException;

public class OkHttpAsyncErrorHandlingExample {
    public static void main(String[] args) {
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url("https://jsonplaceholder.typicode.com/posts/1")
                .build();

        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                System.err.println("Request failed: " + e.getMessage());
                e.printStackTrace();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                try (response) { // try-with-resources for response
                    if (!response.isSuccessful()) {
                        System.err.println("Unexpected code " + response);
                        System.err.println("Response Body: " + response.body().string());
                    } else {
                        System.out.println("Response Body: " + response.body().string());
                    }
                } catch (Exception e) {
                    System.err.println("Error processing response: " + e.getMessage());
                    e.printStackTrace();
                }
            }
        });

        // 異步請求，主線程可能先結(jié)束，實際應(yīng)用中需要適當(dāng)?shù)却?
        try { Thread.sleep(5000); } catch (InterruptedException e) { e.printStackTrace(); }
    }
}

import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.RestTemplate;

public class RestTemplateErrorHandlingExample {
    public static void main(String[] args) {
        RestTemplate restTemplate = new RestTemplate();
        String url = "https://jsonplaceholder.typicode.com/nonexistent"; // 假設(shè)這是一個會返回404的URL

        try {
            String result = restTemplate.getForObject(url, String.class);
            System.out.println("Response Body: " + result);
        } catch (HttpClientErrorException e) {
            System.err.println("Client Error: " + e.getStatusCode() + " - " + e.getStatusText());
            System.err.println("Response Body: " + e.getResponseBodyAsString());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import org.springframework.web.reactive.function.client.WebClient;
import org.springframework.web.reactive.function.client.WebClientResponseException;
import reactor.core.publisher.Mono;

public class WebClientErrorHandlingExample {
    public static void main(String[] args) {
        WebClient webClient = WebClient.create();
        String url = "https://jsonplaceholder.typicode.com/nonexistent"; // 假設(shè)這是一個會返回404的URL

        webClient.get()
                .uri(url)
                .retrieve()
                .bodyToMono(String.class)
                .doOnError(WebClientResponseException.class, error -> {
                    System.err.println("WebClient Error: " + error.getStatusCode() + " - " + error.getStatusText());
                    System.err.println("Response Body: " + error.getResponseBodyAsString());
                })
                .onErrorResume(WebClientResponseException.class, error -> {
                    // 可以在這里返回一個默認(rèn)值或執(zhí)行其他恢復(fù)邏輯
                    return Mono.just("Error occurred: " + error.getStatusCode());
                })
                .subscribe(response -> System.out.println("Response: " + response),
                           throwable -> System.err.println("Unhandled error: " + throwable.getMessage()));

        try { Thread.sleep(2000); } catch (InterruptedException e) { e.printStackTrace(); }
    }
}