    var connectorHoverStyle = {
        lineWidth: 2,
        strokeStyle: "green"
    };

    //端点的颜色样式
    var paintStyle = {
        fillStyle: "#ccc",
        radius: 10,
        lineWidth:6
    };

    // 鼠标悬浮在端点上的样式
    var hoverPaintStyle = {
        fillStyle: "#aaa"
    };


    var hollowCircle = {
        endpoint: ["Dot", { radius: 3 }],  //端点的形状
        connectorStyle: connectorPaintStyle,
        connectorHoverStyle: connectorHoverStyle,
        pa