Java Http请求工具类基于最新版 HttpClient5 Fluent

home 编辑时间 2023/04/13

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## 前言
Java项目Http请求工具类
基于Apache HttpClient依赖最新版

## 折腾
最基本的依赖是
其中最核心的是`httpclient5`
另一个`httpclient5-fluent`是简化代码用的
```xml
<dependency>
 <groupId>org.apache.httpcomponents.client5</groupId>
 <artifactId>httpclient5</artifactId>
 <version>5.2.1</version>
</dependency>
<dependency>
 <groupId>org.apache.httpcomponents.client5</groupId>
 <artifactId>httpclient5-fluent</artifactId>
 <version>5.2.1</version>
</dependency>
```

**先看一个错误示范**
这个报错是因为只引入第二个依赖 `httpclient5-fluent`
第一个核心没引入，就会出现反射错误

```java
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hc/client5/http/config/ConnectionConfig
	at org.apache.hc.client5.http.fluent.Executor.<clinit>(Executor.java:68)
	at org.apache.hc.client5.http.fluent.Request.execute(Request.java:205)
	at com.joinzs.auction.utils.HttpClientUtils.httpGet(HttpClientUtils.java:82)
	at com.joinzs.auction.utils.HttpClientUtils.main(HttpClientUtils.java:105)
Caused by: java.lang.ClassNotFoundException: org.apache.hc.client5.http.config.ConnectionConfig
	at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:352)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
	... 4 more
```

**我的工具类里还用到一个依赖 fastjson**
```xml
<dependency>
 <groupId>com.alibaba.fastjson2</groupId>
 <artifactId>fastjson2</artifactId>
 <version>2.0.27</version>
</dependency>
```

工具类代码
```java
import com.alibaba.fastjson2.JSON;
import com.alibaba.fastjson2.JSONObject;
import org.apache.commons.lang3.StringUtils;
import org.apache.hc.client5.http.fluent.Request;
import org.apache.hc.core5.http.ContentType;
import org.apache.hc.core5.http.io.entity.StringEntity;

import java.io.IOException;
import java.util.Map;

/**
 * HTTP 请求工具类
 *
 * @author zzzmh
 * @email admin@zzzmh.cn
 * @date 2023-4-10 11:25:35
 * 
 * 参考
 * https://hc.apache.org/httpcomponents-client-5.2.x/quickstart.html
 * https://blog.csdn.net/hebiwen95/article/details/126405108
 * 
 */
public class HttpClientUtils {

public static JSONObject doPost(String url, JSONObject header, JSONObject params) {
        return doPost(url, JSON.toJSONString(header), JSON.toJSONString(params));
    }

public static JSONObject doPost(String url, JSONObject params) {
        return doPost(url, JSON.toJSONString(params));
    }

public static JSONObject doGet(String url) {
        return doGet(url, null);
    }

public static JSONObject doPost(String url, String header, String params) {
        return JSONObject.parseObject(httpPost(url, header, params));
    }

public static JSONObject doPost(String url, String params) {
        return doPost(url, null, params);
    }

public static JSONObject doGet(String url, String header) {
        return JSONObject.parseObject(httpGet(url, header));
    }

/**
     * 发送 http post 请求 基本款
     *
     * @param url    请求 url
     * @param header 头部参数 JSON格式的String
     * @param params 请求参数 JSON格式的String
     * @return 返回数据 JSON格式的String
     */
    public static String httpPost(String url, String header, String params) {
        String result = null;
        try {
            Request request = Request.post(url);
            addHeader(request, header);
            addParams(request, params);
            result = request.execute().returnContent().asString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

/**
     * 发送 http get 请求 基本款
     *
     * @param url    请求 url 自己拼参数
     * @param header 头部参数 JSON格式的String
     * @return 返回数据 JSON格式的String
     */
    public static String httpGet(String url, String header) {
        String result = null;
        try {
            Request request = Request.get(url);
            addHeader(request, header);
            result = request.execute().returnContent().asString();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }

public static void addHeader(Request request, String header) {
        if (StringUtils.isNotBlank(header)) {
            JSONObject headers = JSONObject.parseObject(header);
            for (String key : headers.keySet()) {
                request.addHeader(key, headers.getString(key));
            }
        }
    }

public static void addParams(Request request, String json) {
        if (StringUtils.isNotBlank(json)) {
            request.body(new StringEntity(json, ContentType.APPLICATION_JSON));
        }
    }
}
```

使用方法
**非JSON请求**
```java
public static void main(String[] args) {
 String get = httpGet("http://www.baidu.com", null);
}
```

**JSON请求**
```java
public static void main(String[] args) {
    JSONObject object = doPost("https://api.xxx.com", JSONObject.of("参数a", "a", "参数b", "b"));
}
```

### END

参考
https://hc.apache.org/httpcomponents-client-5.2.x/quickstart.html
https://blog.csdn.net/hebiwen95/article/details/126405108

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