使用Apache HttpClient执行GET、POST、PUT和DELETE请求的操作方法_https

apache httpclient 是一个功能强大且灵活的库，用于在java中处理http请求。

它支持多种http方法，包括get、post、put和delete等。

本教程将演示如何使用apache httpclient来执行get、post、put和delete请求。

maven依赖

要使用apache httpclient，您需要在pom.xml文件中添加以下依赖项：

<!-- https://mvnrepository.com/artifact/org.apache.httpcomponents.client5/httpclient5 -->
<dependency>
    <groupid>org.apache.httpcomponents.client5</groupid>
    <artifactid>httpclient5</artifactid>
    <version>5.3</version>
</dependency>

示例场景

我们将创建简单的java类，这些类将向指定的url发送get、post、put和delete请求，并打印响应。

jsonplaceholder api

为了演示目的，我们将使用jsonplaceholder api，该api提供了一个虚拟的在线restful端点，用于测试和原型设计。

get请求

发送get请求的java类

创建一个名为httpclientgetexample的类，代码如下：

import org.apache.hc.client5.http.classic.methods.httpget;
import org.apache.hc.client5.http.classic.methods.closeablehttpresponse;
import org.apache.hc.client5.http.impl.classic.closeablehttpclient;
import org.apache.hc.client5.http.impl.classic.httpclients;
import org.apache.hc.core5.http.io.entity.entityutils;
public class httpclientgetexample {
    public static void main(string[] args) {
        string url = "https://jsonplaceholder.typicode.com/posts/1";
        // 创建httpclient
        try (closeablehttpclient httpclient = httpclients.createdefault()) {
            // 创建httpget请求
            httpget request = new httpget(url);
            // 执行请求
            try (closeablehttpresponse response = httpclient.execute(request)) {
                // 获取http响应状态
                system.out.println("response code: " + response.getcode());
                // 获取http响应内容
                string content = entityutils.tostring(response.getentity());
                system.out.println("response content: \n" + content);
            }
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}

示例输出

response code: 200
response content:
{
"userid": 1,
"id": 1,
"title": "sunt aut facere repellat provident occaecati excepturi optio reprehenderit",
"body": "quia et suscipit\nsuscipit recusandae consequuntur expedita et cum\nreprehenderit molestiae ut ut quas totam\nnostrum rerum est autem sunt rem eveniet architecto"
}

post请求

发送post请求的java类

创建一个名为httpclientpostexample的类，代码如下：

import org.apache.hc.client5.http.classic.methods.httppost;
import org.apache.hc.client5.http.classic.methods.closeablehttpresponse;
import org.apache.hc.client5.http.impl.classic.closeablehttpclient;
import org.apache.hc.client5.http.impl.classic.httpclients;
import org.apache.hc.core5.http.io.entity.stringentity;
import org.apache.hc.core5.http.contenttype;
import org.apache.hc.core5.http.io.entity.entityutils;
public class httpclientpostexample {
    public static void main(string[] args) {
        string url = "https://jsonplaceholder.typicode.com/posts";
        string json = "{\"title\":\"foo\",\"body\":\"bar\",\"userid\":1}";
        // 创建httpclient
        try (closeablehttpclient httpclient = httpclients.createdefault()) {
            // 创建httppost请求
            httppost request = new httppost(url);
            // 设置json负载
            stringentity entity = new stringentity(json, contenttype.application_json);
            request.setentity(entity);
            // 设置头部
            request.setheader("accept", "application/json");
            request.setheader("content-type", "application/json");
            // 执行请求
            try (closeablehttpresponse response = httpclient.execute(request)) {
                // 获取http响应状态
                system.out.println("response code: " + response.getcode());
                // 获取http响应内容
                string content = entityutils.tostring(response.getentity());
                system.out.println("response content: \n" + content);
            }
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}

示例输出

response code: 201
response content:
{
"title": "foo",
"body": "bar",
"userid": 1,
"id": 101
}

put请求

发送put请求的java类

创建一个名为httpclientputexample的类，代码如下：

import org.apache.hc.client5.http.classic.methods.httpput;
import org.apache.hc.client5.http.classic.methods.closeablehttpresponse;
import org.apache.hc.client5.http.impl.classic.closeablehttpclient;
import org.apache.hc.client5.http.impl.classic.httpclients;
import org.apache.hc.core5.http.io.entity.stringentity;
import org.apache.hc.core5.http.contenttype;
import org.apache.hc.core5.http.io.entity.entityutils;
public class httpclientputexample {
    public static void main(string[] args) {
        string url = "https://jsonplaceholder.typicode.com/posts/1";
        string json = "{\"id\":1,\"title\":\"foo\",\"body\":\"bar\",\"userid\":1}";
        // 创建httpclient
        try (closeablehttpclient httpclient = httpclients.createdefault()) {
            // 创建httpput请求
            httpput request = new httpput(url);
            // 设置json负载
            stringentity entity = new stringentity(json, contenttype.application_json);
            request.setentity(entity);
            // 设置头部
            request.setheader("accept", "application/json");
            request.setheader("content-type", "application/json");
            // 执行请求
            try (closeablehttpresponse response = httpclient.execute(request)) {
                // 获取http响应状态
                system.out.println("response code: " + response.getcode());
                // 获取http响应内容
                string content = entityutils.tostring(response.getentity());
                system.out.println("response content: \n" + content);
            }
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}

示例输出

response code: 200
response content:
{
"id": 1,
"title": "foo",
"body": "bar",
"userid": 1
}

delete请求

发送delete请求的java类

创建一个名为httpclientdeleteexample的类，代码如下：

import org.apache.hc.client5.http.classic.methods.httpdelete;
import org.apache.hc.client5.http.classic.methods.closeablehttpresponse;
import org.apache.hc.client5.http.impl.classic.closeablehttpclient;
import org.apache.hc.client5.http.impl.classic.httpclients;
import org.apache.hc.core5.http.io.entity.entityutils;
public class httpclientdeleteexample {
    public static void main(string[] args) {
        string url = "https://jsonplaceholder.typicode.com/posts/1";
        // 创建httpclient
        try (closeablehttpclient httpclient = httpclients.createdefault()) {
            // 创建httpdelete请求
            httpdelete request = new httpdelete(url);
            // 执行请求
            try (closeablehttpresponse response = httpclient.execute(request)) {
                // 获取http响应状态
                system.out.println("response code: " + response.getcode());
                // 获取http响应内容
                string content = entityutils.tostring(response.getentity());
                system.out.println("response content: \n" + content);
            }
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}

示例输出

response code: 200
response content:
{}

额外配置

设置自定义头部：可以通过调用请求对象（如httpget、httppost、httpput、httpdelete）上的setheader方法来设置自定义头部。
处理重定向：默认情况下，apache httpclient会自动处理重定向。您可以使用自定义的httpclientbuilder来自定义这种行为。
设置超时：可以使用requestconfig来设置连接和套接字超时。