小程序的登录，通过前端传过来code，在服务端（java）获取openId.
首先你得有appid以及secret(秘钥).
下面是业务逻辑代码（这里为了方便展示直接写在了controller）
@GetMapping("getCode")
public AjaxResult getCode(String code){
// 授权（必填）
String wxspAppid = "填写小程序appid";
String wxspSecret = "填写小程序密钥";
//默认是authorization_code
String grant_type = "authorization_code";
// 请求参数
String params = "appid=" + wxspAppid + "&secret=" + wxspSecret + "&js_code=" + code + "&grant_type=" + grant_type;
// 发送请求
String sr = HttpRequest.sendPost("https://api.weixin.qq.com/sns/jscode2session", params);
// 解析相应内容（转换成json对象）
JSONObject json = JSONObject.parseObject(sr);
logger.info("解析code请求结果:"+json.toString());
// 获取会话密钥（session_key）
//String session_key = json.getString("session_key");
//获取openId
String openid = json.getString("openid");
return AjaxResult.success(openid);
}
JSONObject 引入的是alibaba的jar
import com.alibaba.fastjson.JSONObject;
<!-- alibaba json 工具 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
</dependency>
HttpRequest工具类类
package com.ckf.common.core.utils;
/**
* @author serence
* @date 2020/12/21 11:47
*/
import com.alibaba.fastjson.JSONObject;
import lombok.extern.slf4j.Slf4j;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import java.util.Map;
@Slf4j
public class HttpRequest {
/**
* 向指定URL发送GET方法的请求
*
* @param url
* 发送请求的URL
* @param param
* 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
* @return URL 所代表远程资源的响应结果
*/
public static String sendGet(String url, String param) {
String result = "";
BufferedReader in = null;
try {
String urlNameString = url + "?" + param;
URL realUrl = new URL(urlNameString);
// 打开和URL之间的连接
URLConnection connection = realUrl.openConnection();
// 设置通用的请求属性
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 建立实际的连接
connection.connect();
// 获取所有响应头字段
Map<String, List<String>> map = connection.getHeaderFields();
// 遍历所有的响应头字段
/*
* for (String key : map.keySet()) { System.out.println(key + "--->"
* + map.get(key)); }
*/
// 定义 BufferedReader输入流来读取URL的响应
in = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
String line;
while ((line = in.readLine()) != null) {
result += line;
}
} catch (Exception e) {
log.error("发送GET请求出现异常:"+e);
}
// 使用finally块来关闭输入流
finally {
try {
if (in != null) {
in.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
return result;
}
/**
* 单参数数据访问
*
*/
public static String sendGet(String url) {
String result = "";
BufferedReader in = null;
try {
String urlNameString = url;
URL realUrl = new URL(urlNameString);
// 打开和URL之间的连接
URLConnection connection = realUrl.openConnection();
// 设置通用的请求属性
connection.setRequestProperty("accept", "*/*");
connection.setRequestProperty("connection", "Keep-Alive");
connection.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 建立实际的连接
connection.connect();
// 获取所有响应头字段
Map<String, List<String>> map = connection.getHeaderFields();
// 遍历所有的响应头字段
/*
* for (String key : map.keySet()) { System.out.println(key + "--->"
* + map.get(key)); }
*/
// 定义 BufferedReader输入流来读取URL的响应
in = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
String line;
while ((line = in.readLine()) != null) {
result += line;
}
} catch (Exception e) {
//System.out.println("发送GET请求出现异常！" + e);
e.printStackTrace();
}
// 使用finally块来关闭输入流
finally {
try {
if (in != null) {
in.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
return result;
}
/**
* 向指定 URL 发送POST方法的请求
*
* @param url
* 发送请求的 URL
* @param param
* 请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
* @return 所代表远程资源的响应结果
*/
public static String sendPost(String url, String param) {
PrintWriter out = null;
BufferedReader in = null;
String result = "";
try {
URL realUrl = new URL(url);
// 打开和URL之间的连接
URLConnection conn = realUrl.openConnection();
// 设置通用的请求属性
conn.setRequestProperty("accept", "*/*");
conn.setRequestProperty("connection", "Keep-Alive");
conn.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 发送POST请求必须设置如下两行
conn.setDoOutput(true);
conn.setDoInput(true);
// 获取URLConnection对象对应的输出流
out = new PrintWriter(conn.getOutputStream());
// 发送请求参数
out.print(param);
// flush输出流的缓冲
out.flush();
// 定义BufferedReader输入流来读取URL的响应
in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
String line;
while ((line = in.readLine()) != null) {
result += line;
}
} catch (Exception e) {
System.out.println("发送 POST 请求出现异常！" + e);
e.printStackTrace();
}
// 使用finally块来关闭输出流、输入流
finally {
try {
if (out != null) {
out.close();
}
if (in != null) {
in.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
return result;
}
public static String doPost(String postUrl, JSONObject obj) {
String lines = "";
StringBuffer sb = new StringBuffer("");
try {
// 创建连接
URL url = new URL(postUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestMethod("POST");
connection.setUseCaches(false);
connection.setInstanceFollowRedirects(true);
connection.setRequestProperty("Content-Type", "application/json");
connection.connect();
// POST请求
DataOutputStream out = new DataOutputStream(connection.getOutputStream());
// out.writeChars(obj.toString());
// out.write(obj.toString().getBytes("UTF-8"));
out.write(obj.toString().getBytes());
out.flush();
out.close();
// 读取响应
BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), "UTF-8"));
while ((lines = reader.readLine()) != null) {
lines = new String(lines.getBytes());
sb.append(lines);
}
System.out.println(sb);
reader.close();
// 断开连接
connection.disconnect();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return sb.toString();
}
}
好了，有问题的小伙伴请留言哦！
