大致步骤如下：

1. 在官网生成appId 与 appSecret，然后通过appId 与 appSecret调用接口获取到Access token

2. 通过Access token调用微信提供的接口获取到jsapi_ticket

3. 最后使用jsapi_ticket、随机字符串、时间戳、url拼接字符串，在使用sha1进行加密得到签名

4. 将appid、时间戳、随机字符串、签名返回给前端

实现代码如下

public class WxUtils {
    private final static String appId = "********";
    private final static String secret = "*****************";
    /**
     * 微信获取 AccessToken
     */
    public static final String  ACCESS_TOKEN = "https://api.weixin.qq.com/cgi-bin/token";
    /**
     * 基础jsapi_ticket请求url
     */
    private final  static String TicketReqUrl = " https://api.weixin.qq.com/cgi-bin/ticket/getticket";
    /**
     * 获取accesstoken
     * @return
     */
    private static AccessTokenVo getAccessToken() {
        // 使用缓存，默认有效期是7200s
        AccessTokenVo token = (AccessTokenVo) RedisUtils.get("accessToken");
        if (token != null) {
            return token;
        }

        HttpResponse response = HttpRequest.get(ACCESS_TOKEN + "?grant_type=client_credential&appid="+ appId +"&secret=" + secret)
                .header("Content-Type", "application/json") // 设置请求头
                .execute();
        // 打印响应结果
        if (response.isOk()) {
            System.out.println("推送请求成功，响应内容：" + response.body());
            AccessTokenVo myObject = JSONUtil.toBean(response.body(), AccessTokenVo.class);
            RedisUtils.set("accessToken", myObject, (long)myObject.getExpires_in(), TimeUnit.SECONDS);
            return myObject;
        } else {
            System.out.println("推送请求失败，状态码：" + response.getStatus() + "，响应内容：" + response.body());
        }
        return null;
    }

    /**
     * 生成随机字符 最长32位
     */
    private static String randomStr(){
        String ss = (Math.random() * 100000000) + "";
        if(ss.length() > 32){
            return ss.substring(0,32);
        }
        return ss;
    }

    /**
     * 获取ticket
     * @return
     */
    private static TicketVo getTicket(String accessToken) {
        // // 使用缓存，默认有效期是7200s
        TicketVo ticket = (TicketVo) RedisUtils.get("ticket");
        if (ticket != null) {
            return ticket;
        }

        HttpResponse response = HttpRequest.get(TicketReqUrl + "?access_token="+ accessToken +"&type=jsapi")
                .header("Content-Type", "application/json") // 设置请求头
                .execute();
        // 打印响应结果
        if (response.isOk()) {
            System.out.println("推送请求成功，响应内容：" + response.body());
            TicketVo myObject = JSONUtil.toBean(response.body(), TicketVo.class);
            RedisUtils.set("ticket", myObject, (long)myObject.getExpires_in(), TimeUnit.SECONDS);
            return myObject;
        } else {
            System.out.println("推送请求失败，状态码：" + response.getStatus() + "，响应内容：" + response.body());
        }
        return null;
    }

    /**
     * 生成签名字符数据
     */
    public static SignVo getSignData(String url){
        AccessTokenVo accessToken = getAccessToken();
        TicketVo ticketVo = getTicket(accessToken.getAccess_token());

        String noncestr = randomStr();
        Date time = new Date();
        long timestamp = time.getTime() / 1000;
        String autograph = autograph(ticketVo.getTicket(), noncestr, timestamp, url);
        SignVo vo = new SignVo();
        vo.setAppId(appId);
        vo.setNonceStr(noncestr);
        vo.setSignature(autograph);
        vo.setTimestamp(timestamp);
        return vo;
    }

    /**
     * 生成签名数据
     */
    private static String autograph(String ticket,String noncestr,long timestamp,String url){
        StringBuilder builder = new StringBuilder();
        builder.append("jsapi_ticket=")
                .append(ticket)
                .append("&noncestr=")
                .append(noncestr)
                .append("&timestamp=")
                .append(timestamp)
                .append("&url=")
                .append(url);
        byte[] bytes = DigestUtils.sha1(builder.toString());
        StringBuilder sb = new StringBuilder();
        for (byte item : bytes) {
            sb.append(Integer.toHexString((item & 0xFF) | 0x100), 1, 3);
        }
        return sb.toString();
    }
}

SignVo

/**
 * 功能描述:
 * @Param:
 * @Return:
 * @Author: zhangfuxiang
 * @Date: 2025/9/17 13:35
 */
@Data
@ApiModel
public class SignVo {

    /**
     * appId
     */
    private String appId;

    /**
     * 时间戳
     */
    private long timestamp;

    /**
     * 随机字符串
     */
    private String nonceStr;

    /**
     * 签名字符串
     */
    private String signature;

}

AccessTokenVo

@Data
@ApiModel
public class AccessTokenVo {

    /**
     * access_token
     */
    private String access_token;

    /**
     * 过期时间
     */
    private int expires_in;

}

TicketVo

@Data
@ApiModel
public class TicketVo {

    /**
     * ticket
     */
    private String ticket;

    /**
     * 过期时间
     */
    private int expires_in;

}