使用Apache HttpClient 4.x进行进行一次Http请求
依赖
xml
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<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.7</version>
</dependency>
请求式样
java
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import org.apache.commons.lang3.StringUtils;
import org.apache.http.Consts;
import org.apache.http.HttpStatus;
import org.apache.http.ParseException;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.entity.ContentType;
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 java.io.IOException;
public class HttpPostUtils {
/**
* @param uri the request address
* @param json the request data that must be a JSON string
* @throws IOException if HTTP connection can not opened or closed successfully
* @throws ParseException if response data can not be parsed successfully
*/
public String retryPostJson(String uri, String json) throws IOException, ParseException {
if (StringUtils.isAnyBlank(uri, json)) {
return null;
}
// 构建HttpClient
CloseableHttpClient client = HttpClients.custom().setRetryHandler(new RetryHandler()).build();
// 构建请求
HttpPost httpPost = new HttpPost(uri);
// 设置请求体
StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
httpPost.setEntity(entity);
// 设置超时时间
RequestConfig config = RequestConfig.custom().setConnectionRequestTimeout(5000) // 超5秒还没返回新的可用链接，抛ConnectionPoolTimeoutException。默认值为0，表示无限等待。
.setConnectTimeout(5000) // 超5秒还没建立链接，抛ConnectTimeoutException。默认值为0，表示无限等待。
.setSocketTimeout(5000) // 超5秒还没返回数据，抛SocketTimeoutException。默认值为0，表示无限等待。
.build();
httpPost.setConfig(config);
// Response
CloseableHttpResponse response = null;
String responseContent = null;
try {
response = client.execute(httpPost, HttpClientContext.create());
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
responseContent = EntityUtils.toString(response.getEntity(), Consts.UTF_8.name());
}
} finally {
if (response != null) {
response.close();
}
if (client != null) {
client.close();
}
}
return responseContent;
}
}
失败重试机制
java
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import org.apache.http.HttpEntityEnclosingRequest;
import org.apache.http.HttpRequest;
import org.apache.http.NoHttpResponseException;
import org.apache.http.client.HttpRequestRetryHandler;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.conn.ConnectTimeoutException;
import org.apache.http.protocol.HttpContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLHandshakeException;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.ConnectException;
import java.net.UnknownHostException;
public class RetryHandler implements HttpRequestRetryHandler {
@Override
public boolean retryRequest(IOException exception, int executionCount, HttpContext context) {
if (executionCount >= 2) {
// 如果已经重试了2次，就放弃
// Do not retry if over max retry count
return false;
}
if (exception instanceof NoHttpResponseException) {
// 如果服务器丢掉了连接，那么就重试
return true;
}
if (exception instanceof SSLHandshakeException) {
// 不要重试SSL握手异常
return false;
}
if (exception instanceof SSLException) {
// SSL握手异常
// SSL handshake exception
return false;
}
if (exception instanceof ConnectTimeoutException) {
// 连接被拒绝
return false;
}
if (exception instanceof InterruptedIOException) {
// An input or output transfer has been terminated
// 超时
return false;
}
if (exception instanceof UnknownHostException) {
// Unknown host 修改代码让不识别主机时重试，实际业务当不识别的时候不应该重试，再次为了演示重试过程，执行会显示retryCount次下面的输出
// 目标服务器不可达
System.out.println("不识别主机重试");
return true;
}
if (exception instanceof ConnectException) {
// Connection refused
return false;
}
HttpClientContext clientContext = HttpClientContext.adapt(context);
HttpRequest request = clientContext.getRequest();
if (!(request instanceof HttpEntityEnclosingRequest)) {
// Retry if the request is considered idempotent
return true;
}
return false;
}
}
模拟解析返回的Json串
c
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public static List<User> parserJsonToUser() {
// 模拟返回的Json串
Map<String, List<String>> map = new HashMap<>();
map.put("name", Arrays.asList("name1", "name2", "name3"));
map.put("age", Arrays.asList("11", "23", "23"));
map.put("num", Arrays.asList("123", "234", "345"));
String json1 = JsonUtils.toJson(map);
System.out.println(json1);
// fastjson
JSONObject jsonObject = JSON.parseObject(json1, Feature.OrderedField);
// 返回的属性
List<String> fields = new ArrayList<>(map.keySet());
// 几份值
int size = jsonObject.getJSONArray(fields.get(0)).size();
List<User> users = new ArrayList<>();
for (int i = 0; i < size; i++) {
User user1 = new User();
for (String field : fields) {
Object value = jsonObject.getJSONArray(field).get(i);
ReflectUtils.setFieldValue(user1, field, value);
}
users.add(user1);
}
System.out.println(users);
return users;
}
结果
{"num":["123","234","345"],"name":["name1","name2","name3"],"age":["11","23","23"]}
[HttpPostUtils.User(name=name1, age=11, num=123), HttpPostUtils.User(name=name2, age=23, num=234), HttpPostUtils.User(name=name3, age=23, num=345)]
参考
使用Apache HttpClient 4.x进行异常重试
Need 学习消化
二十六、CloseableHttpClient的使用和优化