在一个spring-boot项目中，需要请求第三方API，使用JDK原生的URLConnection过于繁琐，功能强大的Apache.HttpClient又需要额外引入，导致微服务程序变大。搜索发现spring原生的RestTemplate已经内置到了spring-boot-starter-web，可以开箱即用，所以实现了一个基于RestTemplate的工具类，如下
WebHelper
import org.apache.commons.lang.IllegalClassException;
import org.apache.http.impl.client.HttpClients;
import org.springframework.http.*;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.lang.NonNull;
import org.springframework.lang.Nullable;
import org.springframework.web.client.RestTemplate;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLContext;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.nio.charset.StandardCharsets;
import java.security.cert.X509Certificate;
import java.util.List;
import java.util.Map;
/**
* @author frank
* @date 2020-07-31 15:34
*/
public class WebHelper {
private static final String[] IP_HEADER_CANDIDATES = {
"X-Forwarded-For",
"Proxy-Client-IP",
"WL-Proxy-Client-IP",
"HTTP_X_FORWARDED_FOR",
"HTTP_X_FORWARDED",
"HTTP_X_CLUSTER_CLIENT_IP",
"HTTP_CLIENT_IP",
"HTTP_FORWARDED_FOR",
"HTTP_FORWARDED",
"HTTP_VIA",
"REMOTE_ADDR"
};
/**
* 获取客户端 IP 地址
*
* @param request 请求实例
* @return 客户端 IP
*/
public static @Nullable
String getClientIpAddress(HttpServletRequest request) {
for (String header : IP_HEADER_CANDIDATES) {
String ip = request.getHeader(header);
if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {
return ip;
}
}
return request.getRemoteAddr();
}
/**
* 发送 HTTPS.GET 请求
*
* @param url 请求地址
* @param params 请求参数
* @param headers 请求头
* @return 响应实体，可能需要对响应结果的状态码进行处理，所以直接返回响应实体
*/
public static ResponseEntity<String> sendGet(String url, Map<String, String> params, Map<String, String> headers) {
return sendRequest(url, params, null, headers, HttpMethod.GET, Boolean.TRUE);
}
/**
* 发送 HTTPS.POST 请求
*
* @param url 请求地址
* @param body 请求体
* @param headers 请求头
* @return 响应实体，可能需要对响应结果的状态码进行处理，所以直接返回响应实体
*/
public static ResponseEntity<String> sendPost(String url, String body, Map<String, String> headers) {
HttpClients.createDefault();
return sendRequest(url, null, body, headers, HttpMethod.POST, Boolean.TRUE);
}
/**
* 使用 springboot 内置的 RestTemplate 发送 http 请求
*
* @param url 请求地址
* @param params 请求参数
* @param body 请求体
* @param headers 请求头
* @param method 请求方法
* @param useSSL 是否使用安全套接字
* @return 响应实体，可能需要对响应结果的状态码进行处理，所以直接返回响应实体
*/
public static ResponseEntity<String> sendRequest(String url, Map<String, String> params, String body,
Map<String, String> headers, HttpMethod method, boolean useSSL) {
RestTemplate rt = useSSL
? new RestTemplate(new HttpsClientRequestFactory())
: new RestTemplate();
// 字符编码设为 UTF-8
List<HttpMessageConverter<?>> converters = rt.getMessageConverters();
converters.set(1, new StringHttpMessageConverter(StandardCharsets.UTF_8));
rt.setMessageConverters(converters);
HttpHeaders httpHeaders = new HttpHeaders();
if (!MapHelper.isEmpty(headers)) {
httpHeaders.setAll(headers);
}
HttpEntity<String> httpEntity = new HttpEntity<>(body, httpHeaders);
if (!MapHelper.isEmpty(params)) {
url = StringHelper.append(url, "?", MapHelper.toUrl(params, "UTF-8"));
}
return rt.exchange(url, method, httpEntity, String.class);
}
/**
* 覆盖 SimpleClientHttpRequestFactory 的安全套接字层SSL
*/
public static class HttpsClientRequestFactory extends SimpleClientHttpRequestFactory {
@Override
protected void prepareConnection(@NonNull HttpURLConnection connection, @NonNull String httpMethod) throws IOException {
// to https connection
if (!(connection instanceof HttpsURLConnection)) {
throw new IllegalClassException("An instance of HttpsURLConnection is expected");
}
HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;
ExceptionExecutor.withTry(() -> {
// new empty X509TrustManager
TrustManager[] trustAllCerts = new TrustManager[]{
new X509TrustManager() {
@Override
public java.security.cert.X509Certificate[] getAcceptedIssuers() {
return null;
}
@Override
public void checkClientTrusted(X509Certificate[] certs, String authType) {
}
@Override
public void checkServerTrusted(X509Certificate[] certs, String authType) {
}
}
};
SSLContext sslContext = SSLContext.getInstance("SSL");
sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
// set to connection
httpsConnection.setSSLSocketFactory(sslContext.getSocketFactory());
httpsConnection.setHostnameVerifier((s, sslSession) -> true);
return null;
});
super.prepareConnection(httpsConnection, httpMethod);
}
}
}
MapHelper
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Map;
import java.util.stream.Collectors;
public class MapHelper {
/**
* 根据指定字符集完成 URL 编码，构造 URL 参数字符串
*
* @param map {@code {"name":"frank", "gender":"male"}}
* @param charset URLEncode 使用的字符集
* @return name=frank&gender=male
*/
public static <K, V> String toUrl(Map<K, V> map, String charset) {
return map.entrySet().stream()
.map(e -> {
K k = e.getKey();
String val = "";
try {
URLEncoder.encode(StringHelper.toStr(e.getValue()), charset);
} catch (UnsupportedEncodingException ex) {
ex.printStackTrace();
}
return StringHelper.join("=", k, val);
})
.collect(Collectors.joining("&"));
}
}
StringHelper
import java.util.Arrays;
import java.util.Objects;
import java.util.stream.Collectors;
public class StringHelper {
private static final String EMPTY = "";
/**
* 以字符串形式拼接多个参数
*
* @param params 如果整个数组为空，返回空串；如果其中值为空，将转为空串
*/
public static String append(Object... params) {
return join(EMPTY, params);
}
/**
* 以字符串形式拼接多个参数，以指定字符串分隔
*
* @param separator 分隔参数的字符串
* @param params 如果整个数组为空，返回空串；如果其中值为空，将转为空串
*/
public static String join(String separator, Object... params) {
if (params == null || params.length == 0) {
return EMPTY;
}
return Arrays.stream(params)
.map(StringHelper::toStr)
.collect(Collectors.joining(separator));
}
/**
* Object 转 String，如果为 null 时返回值为空串而不是 "null"
*/
public static String toStr(Object obj) {
return Objects.toString(obj, EMPTY);
}
}
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