1 编写srv文件
cd ~/workspace/src/package_name
mkdir srv
roscp rospy_tutorials AddTwoInts.srv srv/Sum_Two.srv
2 更改package.xml文件与CMakeList.txt
vim ~/workspace/src/package_name/package.xml
<build_depend>message_generation</build_depend>
<run_depend>message_runtime</run_depend>
vim ~/workspace/src/package_name/CMakelist
find_package(catkin REQUIRED COMPONENTS roscpp rospy std_msgs message_generation)
generate_messages( DEPENDENCIES std_msgs)
add_service_files( FILES Sum_Two.srv)
3 新建server
vim ~/workspace/src/ex1/src/sum_two_server.py
#!/usr/bin/env python
from ex1.srv import *
import rospy
def handle_sum_two(req):
print "Returning [%s + %s = %s]"%(req.a, req.b, (req.a + req.b))
# 貌似是默认的 srvice回调函数的参数中，req.a req.b 是client中传递的数据。不清楚
return Sum_TwoResponse(req.a + req.b)
def sum_two_server():
rospy.init_node('sum_two_server')
#初始化 节点 用节点 发布服务数据
s = rospy.Service('sum_two', Sum_Two, handle_sum_two)
# 声明了一个 'sum_two'的服务， 数据类型为Sum_Two， 调用handles_sum_two回调函数
print "Ready to add two ints."
rospy.spin()
if __name__ == "__main__":
sum_two_server()
4 新建client
vim ~/workspace/src/ex1/sum_two_client.py
#!/usr/bin/env python
import sys
import rospy
from ex1.srv import *
def sum_two_client(x, y):
rospy.wait_for_service('sum_two')
#等待'sum_two'服务开启
try:
sum_two = rospy.ServiceProxy('sum_two', Sum_Two)
#服务开启后，从'sum_two'服务 Sum_Two数据类型关联数据
resp1 = sum_two(x, y)
#将函数定义成模块，用resp1 调用
return resp1.sum
#返回resp1.sum 的值，及sum_two(x,y)函数中sum的参数值
except rospy.ServiceException, e:
print "Service call failed: %s"%e
def usage():
return "%s [x y]"%sys.argv[0]
if __name__ == "__main__":
if len(sys.argv) == 3:
# 当命令行输入的程序 及参数总数为3 里 rosrun exam sum_two_server.py 是一个 后面的数字是两个
x = int(sys.argv[1])
#第一个参数给x
y = int(sys.argv[2])
第二个参数给y
else:
print usage()
sys.exit(1)
#如果参数数目不对则退出
print "Requesting %s+%s"%(x, y)
print "%s + %s = %s"%(x, y, sum_two_client(x, y))
5 python文件改为执行文件
chmod +x ~/workspace/src/ex1/src/sum_two_server.py
chmod +x ~/workspace/src/ex1/src/sum_two_client.py
6 运行程序
cd ~/workspace/src/ex1/src
catkin_make
rosrun ex1 sum_two_server.py
rosrun ex1 sum_two_client.py
