热部署instrumentation工具类

import lombok.extern.slf4j.Slf4j;
import net.bytebuddy.agent.ByteBuddyAgent;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.annotation.Resource;
import java.lang.instrument.Instrumentation;
import java.util.concurrent.TimeUnit;

@Slf4j
@RestController
public class ReloadClassUtil {

/**
 * 手动上传class文件实时更新jvm内存中的字节码文件
 * @param classFile newClassFile
 * @param classPath com.xxx.xxx.xxx
 * @return success/fail
 */
@PostMapping("/reloadClass")
public Result<String> reloadClass(List<MultipartFile> classFiles, String classPath) {
    log.info("reloadClass start, classPath:{}", classPath);
    if (!permission) return new Result<>(ResultCodeEnum.UNAUTHORIZED);
    return reTransformClass(classFiles, classPath);
}

private Result<String> reTransformClass(List<MultipartFile> files, String path){
    try {
        Map<String, String> fileByteMap = new HashMap<>();
        for (MultipartFile file : files) {
            String className = path + "." + file.getOriginalFilename().replace(".class", "");
            reTransform(file.getBytes(), className);
            fileByteMap.put(className, Base64Utils.encodeBase64String(file.getBytes()));
        }
        syncOthersClient(fileByteMap);
        return new Result<>(ResultCodeEnum.SUCCESS);
    } catch (Exception e) {
        log.error("reloadClass exception", e);
        return new Result<>(ResultCodeEnum.INTERNAL_SERVER_ERROR, e.getMessage());
    }
}

/**
 * 重载class
 * @param fileBytes 字节码文件
 * @param classPath 目标包+类名
 */
public static boolean reTransform(byte[] fileBytes, String classPath) throws Exception{
    inst = inst != null ? inst : ByteBuddyAgent.install();
    String targetClass = classPath.replace(".", "/");
    inst.addTransformer((loader, className, classBeingRedefined, protectionDomain, classfileBuffer) ->
            className.equals(targetClass) ? fileBytes : classfileBuffer, true);
    inst.retransformClasses(Class.forName(classPath));
    return true;
}

/**
 * 同步class文件给集群内其他服务器
 */
private void syncOthersClient(Map<String, String> fileByteMap){
    StringBuilder sb = new StringBuilder();
    fileByteMap.forEach((k,v) -> {
        sb.append(k).append(",");
        redisTemplate.opsForValue().set(k, v, cacheSecond, TimeUnit.SECONDS);
    });
    ReloadClassDto body = ReloadClassDto.builder().classPath(sb.substring(0, sb.length()-1)).build();
    mq.sendMsg(body);
}

@Value("${reload.cacheSecond:60}")
private long cacheSecond;

@Value("${reload.permission:false}")
private boolean permission;

private static Instrumentation inst;

@Resource
private RedisTemplate<String, String> redisTemplate;

}