Apache HttpComponents 之 Httpclie

Apache HttpComponents

Apache HttpComponents 项目负责创建和维护一个基于 HTTP 和相关协议的底层 Java 组件工具集。

官网地址 http://hc.apache.org/index.html

这里试图体验下 HttpClient 5.0 的用法

Apache Maven

<dependency>
  <groupId>org.apache.httpcomponents.client5</groupId>
  <artifactId>httpclient5</artifactId>
  <version>5.0.3</version>
</dependency>

Gradle Groovy DSL

implementation 'org.apache.httpcomponents.client5:httpclient5:5.0.3'

Apache HttpComponents – HttpClient Quick Start

http get 和 http post 示例代码

try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
    HttpGet httpGet = new HttpGet("http://httpbin.org/get");
    // The underlying HTTP connection is still held by the response object
    // to allow the response content to be streamed directly from the network socket.
    // In order to ensure correct deallocation of system resources
    // the user MUST call CloseableHttpResponse#close() from a finally clause.
    // Please note that if response content is not fully consumed the underlying
    // connection cannot be safely re-used and will be shut down and discarded
    // by the connection manager.
    try (CloseableHttpResponse response1 = httpclient.execute(httpGet)) {
        System.out.println(response1.getCode() + " " + response1.getReasonPhrase());
        HttpEntity entity1 = response1.getEntity();
        // do something useful with the response body
        // and ensure it is fully consumed
        EntityUtils.consume(entity1);
    }

    HttpPost httpPost = new HttpPost("http://httpbin.org/post");
    List<NameValuePair> nvps = new ArrayList<>();
    nvps.add(new BasicNameValuePair("username", "vip"));
    nvps.add(new BasicNameValuePair("password", "secret"));
    httpPost.setEntity(new UrlEncodedFormEntity(nvps));

    try (CloseableHttpResponse response2 = httpclient.execute(httpPost)) {
        System.out.println(response2.getCode() + " " + response2.getReasonPhrase());
        HttpEntity entity2 = response2.getEntity();
        // do something useful with the response body
        // and ensure it is fully consumed
        EntityUtils.consume(entity2);
    }
}

文件上传 示例代码

package org.apache.hc.client5.http.examples;

import java.io.File;

import org.apache.hc.client5.http.classic.methods.HttpPost;
import org.apache.hc.client5.http.entity.mime.FileBody;
import org.apache.hc.client5.http.entity.mime.MultipartEntityBuilder;
import org.apache.hc.client5.http.entity.mime.StringBody;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.HttpEntity;
import org.apache.hc.core5.http.io.entity.EntityUtils;

/**
 * Example how to use multipart/form encoded POST request.
 */
public class ClientMultipartFormPost {

    public static void main(final String[] args) throws Exception {
        if (args.length != 1)  {
            System.out.println("File path not given");
            System.exit(1);
        }
        try (final CloseableHttpClient httpclient = HttpClients.createDefault()) {
            final HttpPost httppost = new HttpPost("http://localhost:8080" +
                    "/servlets-examples/servlet/RequestInfoExample");

            final FileBody bin = new FileBody(new File(args[0]));
            final StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN);

            final HttpEntity reqEntity = MultipartEntityBuilder.create()
                    .addPart("bin", bin)
                    .addPart("comment", comment)
                    .build();

            httppost.setEntity(reqEntity);

            System.out.println("executing request " + httppost);
            try (final CloseableHttpResponse response = httpclient.execute(httppost)) {
                System.out.println("----------------------------------------");
                System.out.println(response);
                final HttpEntity resEntity = response.getEntity();
                if (resEntity != null) {
                    System.out.println("Response content length: " + resEntity.getContentLength());
                }
                EntityUtils.consume(resEntity);
            }
        }
    }

}

文件上传（并解决中文乱码 --- 进行 ISO-8859-1 编码）示例代码

    // 包含了 对中文字符 的处理 FileBody 和 StringBody
    private static void clientMultipartFormPost() throws IOException {
        try (final CloseableHttpClient httpclient = HttpClients.createDefault()) {
            final HttpPost httppost = new HttpPost("http://localhost:4000" + "/fileUpload");
            
            File file = new File("D:/国徽面1.png");
            String fileName = new String(file.getName().getBytes(), "ISO-8859-1");
            final FileBody bin = new FileBody(file, ContentType.DEFAULT_BINARY, fileName);          
            final StringBody comment = new StringBody(new String("一种 binary 文件".getBytes(), "ISO-8859-1"), ContentType.TEXT_PLAIN);
            final HttpEntity reqEntity = MultipartEntityBuilder.create()
                    .addPart("bin", bin)
                    .addPart("comment", comment)
                    .build();
            
            httppost.setEntity(reqEntity);
            
            System.out.println("executing request " + httppost);
            try (final CloseableHttpResponse response = httpclient.execute(httppost)) {
                System.out.println("----------------------------------------");
                System.out.println(response);
                final HttpEntity resEntity = response.getEntity();
                if (resEntity != null) {
                    System.out.println("Response content length: " + resEntity.getContentLength());
                }
                EntityUtils.consume(resEntity);
            }
        }
    }

This example demonstrates how to send an HTTP request via a proxy （代理）.

package org.apache.hc.client5.http.examples;

import org.apache.hc.client5.http.classic.methods.HttpGet;
import org.apache.hc.client5.http.config.RequestConfig;
import org.apache.hc.client5.http.impl.classic.CloseableHttpClient;
import org.apache.hc.client5.http.impl.classic.CloseableHttpResponse;
import org.apache.hc.client5.http.impl.classic.HttpClients;
import org.apache.hc.core5.http.HttpHost;
import org.apache.hc.core5.http.io.entity.EntityUtils;

/**
 * How to send a request via proxy.
 *
 * @since 4.0
 */
public class ClientExecuteProxy {

    public static void main(final String[] args)throws Exception {
        try (final CloseableHttpClient httpclient = HttpClients.createDefault()) {
            final HttpHost target = new HttpHost("https", "httpbin.org", 443);
            final HttpHost proxy = new HttpHost("http", "127.0.0.1", 8080);

            final RequestConfig config = RequestConfig.custom()
                    .setProxy(proxy)
                    .build();
            final HttpGet request = new HttpGet("/get");
            request.setConfig(config);

            System.out.println("Executing request " + request.getMethod() + " " + request.getUri() +
                    " via " + proxy);

            try (final CloseableHttpResponse response = httpclient.execute(target, request)) {
                System.out.println("----------------------------------------");
                System.out.println(response.getCode() + " " + response.getReasonPhrase());
                System.out.println(EntityUtils.toString(response.getEntity()));
            }
        }
    }

}