okhttp3的基本使用（post发送json示例）

        <!-- https://mvnrepository.com/artifact/com.squareup.okhttp3/okhttp -->
        <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>3.14.9</version>
        </dependency>

package com.qzcsbj.demo;

import okhttp3.*;
import java.io.IOException;
import java.util.concurrent.TimeUnit;

/**
 * @公众号 : 全栈测试笔记
 * @博客 : www.cnblogs.com/uncleyong
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 * @描述 : <>
 */
public class OkHttp3Test {
    public static void main(String[] args) {
        // 定义接口的URL
        String url = "http://localhost:8089/qzcsbj/user/login";
        
        // 接口的请求参数
        String requestParameter = "{\n" +
                "  \"username\": \"qzcsbj\",\n" +
                "  \"password\": \"123456\"\n" +
                "}";
        // 封装请求体
        MediaType mediaType = MediaType.parse("application/json");
        RequestBody requestBody = RequestBody.create(mediaType, requestParameter);

        // 封装请求对象
        Request request = new Request.Builder().post(requestBody)
                .addHeader("Content-Type", "application/json")
                .url(url).build();

        // 创建okhttp工具类
        OkHttpClient okHttpClient = new OkHttpClient.Builder()
                .connectTimeout(30, TimeUnit.SECONDS)
                .writeTimeout(30, TimeUnit.SECONDS)
                .readTimeout(30, TimeUnit.SECONDS)
                .build();

        try {
            // 执行这个请求对象
            Response response = okHttpClient.newCall(request).execute();
            System.out.println(response.body().string());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}