java 利用HttpClient PostMethod提交json数据操作

下面是详细讲解Java利用HttpClient PostMethod提交JSON数据操作的完整攻略：

1. 导入HttpClient依赖

首先需要在项目中使用HttpClient库，可以使用Maven等方式导入依赖，例如：

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5</version>
</dependency>

2. 创建HttpClient对象

使用HttpClient发送HTTP请求需要创建HttpClient对象，在Java中可以使用HttpClientBuilder创建，例如：

CloseableHttpClient httpClient = HttpClientBuilder.create().build();

3. 创建HttpPost对象

发送POST请求需要创建HttpPost对象，同时设置请求的URL，例如：

String url = "http://example.com/api";
HttpPost httpPost = new HttpPost(url);

4. 设置请求头

如果需要设置请求头，可以使用setHeader方法设置，例如：

httpPost.setHeader("Content-Type", "application/json");

5. 设置JSON数据

将JSON数据设置到HttpPost对象的Entity中，需要创建StringEntity对象，并将JSON字符串作为参数传递，例如：

String json = "{\"name\":\"张三\",\"age\":25}";
StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
httpPost.setEntity(entity);

6. 发送请求并获取响应

调用HttpClient的execute方法可以发送请求，返回一个HttpResponse对象，例如：

HttpResponse response = httpClient.execute(httpPost);

可以进一步获取响应的状态码、实体、请求头等信息，例如：

int statusCode = response.getStatusLine().getStatusCode();
HttpEntity responseBody = response.getEntity();
Header[] headers = response.getAllHeaders();

7. 释放资源

使用完HttpClient对象之后需要释放资源，可以使用CloseableHttpClient的close方法，例如：

httpClient.close();

示例一

下面通过一个示例来演示使用HttpClient PostMethod提交JSON数据的操作：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
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.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

import java.net.URI;

public class HttpPostJsonExample {

    public static void main(String[] args) throws Exception {

        CloseableHttpClient httpClient = HttpClientBuilder.create().build();

        String url = "http://example.com/api";

        URI uri = new URIBuilder(url).build();

        HttpPost httpPost = new HttpPost(uri);
        httpPost.setHeader("Content-Type", "application/json");

        String json = "{\"name\":\"张三\",\"age\":25}";
        StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
        httpPost.setEntity(entity);

        HttpResponse response = httpClient.execute(httpPost);

        int statusCode = response.getStatusLine().getStatusCode();
        HttpEntity responseBody = response.getEntity();
        String responseJson = EntityUtils.toString(responseBody);

        System.out.println("Response status code: " + statusCode);
        System.out.println("Response JSON data: " + responseJson);

        httpClient.close();
    }

}

示例二

下面再通过另一个示例来演示使用HttpClient PostMethod提交JSON数据的操作：

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
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.HttpClientBuilder;
import org.apache.http.util.EntityUtils;

public class HttpPostJsonExample {

    public static void main(String[] args) throws Exception {

        CloseableHttpClient httpClient = HttpClientBuilder.create().build();

        String url = "http://example.com/api";

        HttpPost httpPost = new HttpPost(url);
        httpPost.setHeader("Content-Type", "application/json");

        String json = "{\"name\":\"李四\",\"age\":30}";
        StringEntity entity = new StringEntity(json, ContentType.APPLICATION_JSON);
        httpPost.setEntity(entity);

        HttpResponse response = httpClient.execute(httpPost);

        int statusCode = response.getStatusLine().getStatusCode();
        HttpEntity responseBody = response.getEntity();
        String responseJson = EntityUtils.toString(responseBody);

        System.out.println("Response status code: " + statusCode);
        System.out.println("Response JSON data: " + responseJson);

        httpClient.close();
    }

}

以上就是Java利用HttpClient PostMethod提交JSON数据操作的完整攻略，同时提供了两个示例说明。希望对你有所帮助！