HttpClient使用方法总结及工具类封装

1. 引入httpclient依赖

首先，需要确认项目中是否已引入过httpclient依赖，如果没有引入过，需要在pom.xml中添加以下代码引入httpclient依赖：

<dependency>

    <groupId>org.apache.httpcomponents</groupId>

    <artifactId>httpclient</artifactId>

    <version>4.5.13</version>

</dependency>

2. 发送GET请求

2.1 发送GET请求(无参数)

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doGet() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpGet httpGet = new HttpGet("https://www.example.com/getDataList");

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

2.2 发送GET请求(带参数)

第一种方法是直接在url上拼接上参数，如下所示：

HttpGet httpGet = new HttpGet("https://www.example.com/getDataList?pageIndex=1&pageSize=20");

第二种方法是使用URIBuilder添加参数，如下所示：

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.client.utils.URIBuilder;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.net.URISyntaxException;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doGet() throws IOException, URISyntaxException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            URIBuilder uriBuilder = new URIBuilder("https://www.example.com/getDataList");

            uriBuilder.addParameter("pageIndex", "1");

            uriBuilder.addParameter("pageSize", "20");

            HttpGet httpGet = new HttpGet(uriBuilder.build());

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

3. 发送POST请求

3.1 发送POST请求(无参数)

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doPost() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpPost httpPost = new HttpPost("https://www.example.com/updateData");

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPost)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

3.2 发送POST请求(带参数、form表单方式)

import org.apache.http.HttpStatus;

import org.apache.http.NameValuePair;

import org.apache.http.client.entity.UrlEncodedFormEntity;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.nio.charset.StandardCharsets;

import java.util.ArrayList;

import java.util.List;

public class HttpClientUtils {

    public static String doPost() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpPost httpPost = new HttpPost("https://www.example.com/updateData");

            List<NameValuePair> params = new ArrayList<>();

            params.add(new BasicNameValuePair("id", "1"));

            params.add(new BasicNameValuePair("name", "新名字"));

            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, StandardCharsets.UTF_8);

            httpPost.setEntity(formEntity);

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPost)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

3.3 发送POST请求(带参数、json方式)

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPost;

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;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doPost() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpPost httpPost = new HttpPost("https://www.example.com/updateData");

            String jsonBody = "{\"id\":\"1\",\"name\":新名字}";

            StringEntity stringEntity = new StringEntity(jsonBody);

            stringEntity.setContentType("application/json;charset=utf-8");

            httpPost.setEntity(stringEntity);

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPost)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

4. 发送PUT请求

4.1 发送PUT请求(无参数)

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPut;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doPut() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpPut httpPut = new HttpPut("https://www.example.com/updateData");

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPut)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

4.2 发送PUT请求(带参数、form表单方式)

import org.apache.http.HttpStatus;

import org.apache.http.NameValuePair;

import org.apache.http.client.entity.UrlEncodedFormEntity;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPut;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.message.BasicNameValuePair;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.nio.charset.StandardCharsets;

import java.util.ArrayList;

import java.util.List;

public class HttpClientUtils {

    public static String doPut() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpPut httpPut = new HttpPut("https://www.example.com/updateData");

            List<NameValuePair> params = new ArrayList<>();

            params.add(new BasicNameValuePair("id", "1"));

            params.add(new BasicNameValuePair("name", "新名字"));

            UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, StandardCharsets.UTF_8);

            httpPut.setEntity(formEntity);

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPut)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

4.3 发送PUT请求(带参数、json方式)

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpPut;

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;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doPut() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpPut httpPut = new HttpPut("https://www.example.com/updateData");

            String jsonBody = "{\"id\":\"1\",\"name\":新名字}";

            StringEntity stringEntity = new StringEntity(jsonBody);

            stringEntity.setContentType("application/json;charset=utf-8");

            httpPut.setEntity(stringEntity);

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpPut)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

5. 发送DELETE请求

5.1 发送DELETE请求(无参数)

import org.apache.http.HttpStatus;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpDelete;

import org.apache.http.impl.client.CloseableHttpClient;

import org.apache.http.impl.client.HttpClients;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.nio.charset.StandardCharsets;

public class HttpClientUtils {

    public static String doDelete() throws IOException {

        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {

            HttpDelete httpDelete = new HttpDelete("https://www.example.com/updateData");

            try (CloseableHttpResponse httpResponse = httpClient.execute(httpDelete)) {

                if (httpResponse.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {

                    return EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

                }

                return null;

            }

        }

    }

}

6. 添加请求头

一般情况下，请求第三方接口都需要签名、时间戳等请求头，以POST请求为例，添加请求头的代码如下所示：

httpPost.setHeader("Content-Type", "application/json;charset=utf-8");

httpPost.setHeader("signature", "3045022100875efcef9eb54626bb0168a6baa7c61265d0001d49243f");

httpPost.setHeader("timestamp", String.valueOf(System.currentTimeMillis()));

GET请求、PUT请求、DELETE请求添加请求头的方法同上。

7. 超时时间设置

如果需要自定义HTTP请求的连接超时时间和数据传输超时时间，代码如下所示（以POST请求为例）：

RequestConfig requestConfig = RequestConfig.custom()

                    .setConnectTimeout(5000)

                    .setSocketTimeout(10000)

                    .build();

httpPost.setConfig(requestConfig);

GET请求、PUT请求、DELETE请求设置超时时间的方法同上。

8.工具类封装

完整的工具类代码如下所示：

import org.apache.http.HttpEntity;

import org.apache.http.HttpStatus;

import org.apache.http.NameValuePair;

import org.apache.http.client.config.RequestConfig;

import org.apache.http.client.entity.UrlEncodedFormEntity;

import org.apache.http.client.methods.CloseableHttpResponse;

import org.apache.http.client.methods.HttpDelete;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.client.methods.HttpPost;

import org.apache.http.client.methods.HttpPut;

import org.apache.http.client.methods.HttpRequestBase;

import org.apache.http.client.utils.URIBuilder;

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.message.BasicNameValuePair;

import org.apache.http.util.EntityUtils;

import java.io.IOException;

import java.net.URISyntaxException;

import java.nio.charset.StandardCharsets;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

public class HttpClientUtils {

    /**

     * 连接建立超时时间(单位:毫秒)

     */

    private static final int CONNECT_TIMEOUT = 5000;

    /**

     * 数据传输超时时间(单位:毫秒)

     */

    private static final int SOCKET_TIMEOUT = 10000;

    /**

     * 执行GET请求

     *

     * @param url     请求地址

     * @param headers 请求头

     * @return 响应内容字符串

     */

    public static String doGet(String url, Map<String, String> headers) throws IOException {

        HttpGet httpGet = new HttpGet(url);

        // 设置请求头

        setHeaders(httpGet, headers);

        return executeRequest(httpGet);

    }

    /**

     * 执行GET请求

     *

     * @param url     请求地址

     * @param headers 请求头

     * @param params  请求参数

     * @return 响应内容字符串

     */

    public static String doGet(String url, Map<String, String> headers, Map<String, String> params) throws IOException, URISyntaxException {

        URIBuilder uriBuilder = new URIBuilder(url);

        // 设置请求参数

        if (params != null && !params.isEmpty()) {

            for (Map.Entry<String, String> entry : params.entrySet()) {

                uriBuilder.setParameter(entry.getKey(), entry.getValue());

            }

        }

        HttpGet httpGet = new HttpGet(uriBuilder.build());

        // 设置请求头

        setHeaders(httpGet, headers);

        return executeRequest(httpGet);

    }

    /**

     * 执行POST请求(表单方式)

     *

     * @param url 请求地址

     * @return 响应内容字符串

     */

    public static String doPost(String url) throws IOException {

        return doPost(url, null, null);

    }

    /**

     * 执行POST请求(表单方式)

     *

     * @param url     请求地址

     * @param headers 请求头

     * @return 响应内容字符串

     */

    public static String doPost(String url, Map<String, String> headers) throws IOException {

        return doPost(url, headers, null);

    }

    /**

     * 执行POST请求(表单方式)

     *

     * @param url     请求地址

     * @param headers 请求头

     * @param params  请求参数

     * @return 响应内容字符串

     */

    public static String doPost(String url, Map<String, String> headers, Map<String, String> params) throws IOException {

        HttpPost httpPost = new HttpPost(url);

        // 设置请求头

        setHeaders(httpPost, headers);

        // 构建表单参数

        if (params != null) {

            List<NameValuePair> paramList = new ArrayList<>();

            for (Map.Entry<String, String> entry : params.entrySet()) {

                paramList.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));

            }

            httpPost.setEntity(new UrlEncodedFormEntity(paramList, StandardCharsets.UTF_8));

        }

        return executeRequest(httpPost);

    }

    /**

     * 执行POST请求(JSON格式)

     *

     * @param url     请求地址

     * @param headers 请求头

     * @return 响应内容字符串

     */

    public static String doPostJson(String url, Map<String, String> headers) throws IOException {

        return doPostJson(url, headers, null);

    }

    /**

     * 执行POST请求(JSON格式)

     *

     * @param url      请求地址

     * @param headers  请求头

     * @param jsonBody JSON请求体字符串

     * @return 响应内容字符串

     */

    public static String doPostJson(String url, Map<String, String> headers, String jsonBody) throws IOException {

        HttpPost httpPost = new HttpPost(url);

        // 添加JSON请求头

        addJsonHeader(httpPost, headers);

        // 添加自定义请求头

        setHeaders(httpPost, headers);

        // 设置JSON请求体

        if (jsonBody != null) {

            StringEntity entity = new StringEntity(jsonBody,

                    ContentType.APPLICATION_JSON.withCharset(StandardCharsets.UTF_8));

            httpPost.setEntity(entity);

        }

        return executeRequest(httpPost);

    }

    /**

     * 执行PUT请求(JSON格式)

     *

     * @param url      请求地址

     * @param headers  请求头

     * @param jsonBody JSON请求体字符串

     * @return 响应内容字符串

     */

    public static String doPut(String url, Map<String, String> headers, String jsonBody) throws IOException {

        HttpPut httpPut = new HttpPut(url);

        // 添加JSON请求头

        addJsonHeader(httpPut, headers);

        // 添加自定义请求头

        setHeaders(httpPut, headers);

        // 设置JSON请求体

        if (jsonBody != null) {

            StringEntity entity = new StringEntity(jsonBody,

                    ContentType.APPLICATION_JSON.withCharset(StandardCharsets.UTF_8));

            httpPut.setEntity(entity);

        }

        return executeRequest(httpPut);

    }

    /**

     * 执行DELETE请求

     *

     * @param url     请求地址

     * @param headers 请求头

     * @return 响应内容字符串

     */

    public static String doDelete(String url, Map<String, String> headers) throws IOException {

        HttpDelete httpDelete = new HttpDelete(url);

        // 设置请求头

        setHeaders(httpDelete, headers);

        return executeRequest(httpDelete);

    }

    /**

     * 创建带超时配置的HttpClient

     *

     * @return HttpClient实例

     */

    private static CloseableHttpClient createHttpClient() {

        RequestConfig requestConfig = RequestConfig.custom()

                .setConnectTimeout(CONNECT_TIMEOUT)

                .setSocketTimeout(SOCKET_TIMEOUT)

                .build();

        return HttpClients.custom()

                .setDefaultRequestConfig(requestConfig)

                .build();

    }

    /**

     * 添加JSON请求头

     *

     * @param httpRequest HTTP请求对象

     * @param headers     请求头

     */

    private static void addJsonHeader(HttpRequestBase httpRequest, Map<String, String> headers) {

        if (headers == null || !headers.containsKey("Content-Type")) {

            httpRequest.addHeader("Content-Type", "application/json;charset=utf-8");

        }

    }

    /**

     * 设置请求头

     *

     * @param httpRequest HTTP请求对象

     * @param headers     请求头

     */

    private static void setHeaders(HttpRequestBase httpRequest, Map<String, String> headers) {

        if (headers == null || headers.isEmpty()) {

            return;

        }

        for (Map.Entry<String, String> entry : headers.entrySet()) {

            httpRequest.setHeader(entry.getKey(), entry.getValue());

        }

    }

    /**

     * 统一执行请求并处理响应

     *

     * @param httpRequest HTTP请求对象

     * @return 响应内容字符串

     */

    private static String executeRequest(HttpRequestBase httpRequest) throws IOException {

        try (CloseableHttpClient httpClient = createHttpClient()) {

            try (CloseableHttpResponse response = httpClient.execute(httpRequest)) {

                return handleResponse(response);

            }

        }

    }

    /**

     * 处理响应结果

     *

     * @param response HTTP响应对象

     * @return 响应内容字符串

     */

    private static String handleResponse(CloseableHttpResponse response) throws IOException {

        int statusCode = response.getStatusLine().getStatusCode();

        if (statusCode != HttpStatus.SC_OK) {

            throw new RuntimeException("HTTP请求失败，状态码：" + statusCode);

        }

        HttpEntity entity = response.getEntity();

        if (entity != null) {

            return EntityUtils.toString(entity, StandardCharsets.UTF_8);

        }

        return null;

    }

}

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