[Py4J]从Pythyon端启动Py4J

• Jar包没有main class。启动阻塞，直到JVM启动，Python才会尝试连接

• java_server = JavaGateway.launch_gateway(java_path=__java_home, classpath=__class_path, die_on_exit=True, jarpath=__py4j_jar,
                                    javaopts=["-Djava.library.path=" + dylib, '-Djava.awt.headless=true', "-DWORKDIR=" + work_dir, "-Xmx1024m"])
  client = java_server.jvm.MainClass.getFactoryInstance()

  
  
  

• Jar包有main class。启动非阻塞，可能导致JVM没有启动，Python就去连接的错误

• command = [__java_home, '-classpath', __class_path,
             "-Djava.library.path=" + dylib, '-Djava.awt.headless=true', "-DWORKDIR=" + work_dir, __jar_name]
  proc = subprocess.Popen(command, stdout=subprocess.PIPE, stdin=subprocess.PIPE, stderr=open(os.devnull, "w"), **{})
  java_gateway = JavaGateway()
  client = java_gateway.entry_point