HttpURLconnection使用get无参请求

一时失言乱红尘 2023-06-22 09:29 81阅读 0赞

1、在pom.xml中添加依赖包

<dependency>
    			<groupId>com.alibaba</groupId>
    			<artifactId>fastjson</artifactId>
    			<version>1.2.46</version>
    		</dependency>
    		<dependency>
    			<groupId>org.apache.commons</groupId>
    			<artifactId>commons-lang3</artifactId>
    			<version>3.9</version>
    		</dependency>

2、创建测试类（HttpURLconnectionTest1.java）

package com.jeff;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.UnsupportedEncodingException;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    import org.apache.commons.lang3.StringUtils;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONArray;
    import com.alibaba.fastjson.JSONObject;
    import com.jeff.entity.SysUser;
    
    public class HttpURLconnectionTest1 { 
    
    	public static void main(String[] args) { 
    
    		try { 
    			URL url = new URL("http://localhost:8080/getUserList");
    			// 得到connection对象。
    			HttpURLConnection connection = (HttpURLConnection) url.openConnection();
    			// 设置网络连接超时时间
    			connection.setConnectTimeout(3000);
    			// 设置请求方式
    			connection.setRequestMethod("GET");
    			// 连接
    			connection.connect();
    			// 得到响应码
    			int responseCode = connection.getResponseCode();
    			if (responseCode == HttpURLConnection.HTTP_OK) { 
    				// 得到响应流
    				InputStream inputStream = connection.getInputStream();
    				// 将响应流转换成字符串
    				String jsonStr = inputStreamToString(inputStream);
    				if (StringUtils.isNotBlank(jsonStr)) { 
    					JSONObject jsonObject = JSON.parseObject(jsonStr);
    					Long total = jsonObject.getLong("total");
    					Integer code = jsonObject.getInteger("code");
    					System.out.println("total：" + total + "，code：" + code);
    					JSONArray results = jsonObject.getJSONArray("results");
    					if (results.size() > 0) { 
    						for (int i = 0; i < results.size(); i++) { 
    							// 遍历 jsonArray 数组，把每一个对象转成 json 对象
    							JSONObject job = results.getJSONObject(i);
    							SysUser user = JSONObject.toJavaObject(job, SysUser.class);
    							System.out.println(user.toString());
    						}
    					}
    				}
    			}
    
    		} catch (Exception e) { 
    			e.printStackTrace();
    		}
    	}
    
    	/** * * @description: 将输入流转换成字符串 * @author: Jeff * @date: 2019年12月15日 * @param inputStream 输入流 * @return */
    	private static String inputStreamToString(InputStream inputStream) { 
    		StringBuffer buffer = new StringBuffer();
    		InputStreamReader inputStreamReader;
    		try { 
    			inputStreamReader = new InputStreamReader(inputStream, "utf-8");
    			BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
    			String str = null;
    			while ((str = bufferedReader.readLine()) != null) { 
    				buffer.append(str);
    			}
    			// 释放资源
    			bufferedReader.close();
    			inputStreamReader.close();
    			inputStream.close();
    		} catch (UnsupportedEncodingException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    		return buffer.toString();
    	}
    
    }

3、控制台输出结果  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191215205409361.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NTczOTcyMA==,size_16,color_FFFFFF,t_70