使用Java发送POST请求的四种方式

import java.io.bufferedreader;
import java.io.inputstreamreader;
import java.io.outputstream;
import java.net.httpurlconnection;
import java.net.url;
import java.nio.charset.standardcharsets;

public class postrequestexample {
    public static void main(string[] args) {
        try {
            // 请求url
            string url = "https://example.com/api";
            
            // 创建连接
            url obj = new url(url);
            httpurlconnection con = (httpurlconnection) obj.openconnection();
            
            // 设置请求方法
            con.setrequestmethod("post");
            
            // 设置请求头
            con.setrequestproperty("content-type", "application/json");
            con.setrequestproperty("accept", "application/json");
            
            // 请求体数据
            string requestbody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
            
            // 启用输出流
            con.setdooutput(true);
            
            // 发送请求体
            try(outputstream os = con.getoutputstream()) {
                byte[] input = requestbody.getbytes(standardcharsets.utf_8);
                os.write(input, 0, input.length);
            }
            
            // 获取响应码
            int responsecode = con.getresponsecode();
            system.out.println("response code: " + responsecode);
            
            // 读取响应
            try(bufferedreader br = new bufferedreader(
                new inputstreamreader(con.getinputstream(), standardcharsets.utf_8))) {
                stringbuilder response = new stringbuilder();
                string responseline;
                while ((responseline = br.readline()) != null) {
                    response.append(responseline.trim());
                }
                system.out.println("response: " + response.tostring());
            }
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}

<dependency>
    <groupid>org.apache.httpcomponents</groupid>
    <artifactid>httpclient</artifactid>
    <version>4.5.13</version>
</dependency>

代码示例：

import org.apache.http.httpentity;
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;

public class httpclientpostexample {
    public static void main(string[] args) {
        try (closeablehttpclient httpclient = httpclients.createdefault()) {
            // 创建post请求
            httppost httppost = new httppost("https://example.com/api");
            
            // 设置请求头
            httppost.setheader("content-type", "application/json");
            httppost.setheader("accept", "application/json");
            
            // 设置请求体
            string requestbody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
            httppost.setentity(new stringentity(requestbody));
            
            // 执行请求
            try (closeablehttpresponse response = httpclient.execute(httppost)) {
                // 获取响应码
                int statuscode = response.getstatusline().getstatuscode();
                system.out.println("response code: " + statuscode);
                
                // 获取响应体
                httpentity entity = response.getentity();
                if (entity != null) {
                    string result = entityutils.tostring(entity);
                    system.out.println("response: " + result);
                }
            }
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}

<dependency>
    <groupid>org.springframework.boot</groupid>
    <artifactid>spring-boot-starter-web</artifactid>
    <version>2.5.0</version>
</dependency>

代码示例：

import org.springframework.http.*;
import org.springframework.web.client.resttemplate;

public class resttemplatepostexample {
    public static void main(string[] args) {
        // 创建resttemplate实例
        resttemplate resttemplate = new resttemplate();
        
        // 请求url
        string url = "https://example.com/api";
        
        // 设置请求头
        httpheaders headers = new httpheaders();
        headers.setcontenttype(mediatype.application_json);
        headers.setaccept(collections.singletonlist(mediatype.application_json));
        
        // 请求体数据
        string requestbody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
        
        // 创建请求实体
        httpentity<string> requestentity = new httpentity<>(requestbody, headers);
        
        // 发送post请求
        responseentity<string> response = resttemplate.postforentity(url, requestentity, string.class);
        
        // 获取响应信息
        system.out.println("response code: " + response.getstatuscodevalue());
        system.out.println("response body: " + response.getbody());
    }
}

import java.net.uri;
import java.net.http.httpclient;
import java.net.http.httprequest;
import java.net.http.httpresponse;
import java.time.duration;

public class java11httpclientexample {
    public static void main(string[] args) {
        // 创建httpclient
        httpclient httpclient = httpclient.newbuilder()
                .version(httpclient.version.http_1_1)
                .connecttimeout(duration.ofseconds(10))
                .build();
        
        // 请求体
        string requestbody = "{\"key1\":\"value1\",\"key2\":\"value2\"}";
        
        // 创建httprequest
        httprequest request = httprequest.newbuilder()
                .uri(uri.create("https://example.com/api"))
                .header("content-type", "application/json")
                .header("accept", "application/json")
                .post(httprequest.bodypublishers.ofstring(requestbody))
                .build();
        
        try {
            // 发送请求
            httpresponse<string> response = httpclient.send(
                    request, httpresponse.bodyhandlers.ofstring());
            
            // 输出结果
            system.out.println("status code: " + response.statuscode());
            system.out.println("response body: " + response.body());
        } catch (exception e) {
            e.printstacktrace();
        }
    }
}