实现思路：

1：添加绘制工具的监听事件

2：遍历取出坐标集合

copy代码直接运行测试即可（如果不需要获取经纬度，删除掉相应的方法代码即可）

<!DOCTYPE html>    
<html>    
<head>    
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />    
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no" />    
    <style type="text/css">    
    body, html{width: 100%;height: 100%;margin:0;font-family:"微软雅黑";}    
    #allmap {width: 100%; height:500px; overflow: hidden;}    
    #result {width:100%;font-size:12px;}    
    dl,dt,dd,ul,li{    
        margin:0;    
        padding:0;    
        list-style:none;    
    }    
    p{font-size:12px;}    
    dt{    
        font-size:14px;    
        font-family:"微软雅黑";    
        font-weight:bold;    
        border-bottom:1px dotted #000;    
        padding:5px 0 5px 5px;    
        margin:5px 0;    
    }    
    dd{    
        padding:5px 0 0 5px;    
    }    
    li{    
        line-height:28px;    
    }    
    </style>    
     <script type="text/javascript" src="http://api.map.baidu.com/api?v=2.0&ak=F0i6SrLmHquLVNLCqpExxPrj8mWVdFwx"></script>    
    <!--加载鼠标绘制工具-->    
    <script type="text/javascript" src="http://api.map.baidu.com/library/DrawingManager/1.4/src/DrawingManager_min.js"></script>    
    <link rel="stylesheet" href="http://api.map.baidu.com/library/DrawingManager/1.4/src/DrawingManager_min.css" />    
    <!--加载检索信息窗口-->    
    <script type="text/javascript" src="http://api.map.baidu.com/library/SearchInfoWindow/1.4/src/SearchInfoWindow_min.js"></script>    
    <link rel="stylesheet" href="http://api.map.baidu.com/library/SearchInfoWindow/1.4/src/SearchInfoWindow_min.css" />    
    <title>百度地图API功能演示</title>    
</head>    
<body>    
    <div id="allmap" style="overflow:hidden;zoom:1;position:relative;">       
        <div id="map" style="height:100%;-webkit-transition: all 0.5s ease-in-out;transition: all 0.5s ease-in-out;">    
       </div>    
    </div>    
    <div id="result">    
        <input type="button" value="获取绘制的覆盖物个数" onclick="alert(overlays.length)"/>    
        <input type="button" value="清除所有覆盖物" onclick="clearAll()"/>    
        <input type="button"  value="获取多边形的顶点" onclick="getPoint()"/><br/>    
        <input type="button"  value="开启线、面编辑功能" onclick="Editing('enable')"/>    
        <input type="button"  value="关闭线、面编辑功能" onclick="Editing('disable')"/>    
        <input type="button"  value="显示原有多边形" onclick="showPolygon(this)" /><br/>    
            
        <input type="button"  value="画多边形" onclick="draw(BMAP_DRAWING_POLYGON)" />    
         <input type="button"  value="画矩形" onclick="draw(BMAP_DRAWING_RECTANGLE)" />    
          <input type="button"  value="画线" onclick="draw(BMAP_DRAWING_POLYLINE)" />     
          <!-- <input type="button"  value="画点" onclick="draw(BMAP_DRAWING_MARKER)" />-->    
          <span>右键获取任意点的经纬度</span>    
    </div>    
    <div id="resultShape"></div>    
     <div id="shape">坐标为</div>    
          
<script type="text/javascript">    
    function $(id){    
    return document.getElementById(id);    
}    
    
    // 百度地图API功能    
    var map = new BMap.Map('map');    
    var poi = new BMap.Point(113.948913,22.530844);    
    map.centerAndZoom(poi, 16);    
    map.enableScrollWheelZoom();      
    var overlays = [];    
    var overlaycomplete = function(e){    
        overlays.push(e.overlay);     
    };    
    var styleOptions = {    
        strokeColor:"red",    //边线颜色。    
        fillColor:"red",      //填充颜色。当参数为空时，圆形将没有填充效果。    
        strokeWeight: 3,       //边线的宽度，以像素为单位。    
        strokeOpacity: 0.8,    //边线透明度，取值范围0 - 1。    
        fillOpacity: 0.6,      //填充的透明度，取值范围0 - 1。    
        strokeStyle: 'solid' //边线的样式，solid或dashed。    
    }    
        
    //实例化鼠标绘制工具    
    var drawingManager = new BMapLib.DrawingManager(map, {    
        isOpen: false, //是否开启绘制模式    
        //enableDrawingTool: true, //是否显示工具栏    
        drawingToolOptions: {    
            anchor: BMAP_ANCHOR_TOP_RIGHT, //位置    
            offset: new BMap.Size(5, 5), //偏离值    
        },    
        circleOptions: styleOptions, //圆的样式    
        polylineOptions: styleOptions, //线的样式    
        polygonOptions: styleOptions, //多边形的样式    
        rectangleOptions: styleOptions //矩形的样式    
    });      
        
     //添加鼠标绘制工具监听事件，用于获取绘制结果    
    drawingManager.addEventListener('overlaycomplete', overlaycomplete);    
        
    map.addEventListener("rightclick",function(e){    
        if(confirm(e.point.lng + "," + e.point.lat)){    
            $("shape").innerHTML=$("shape").innerHTML+" <br/>("+e.point.lng+","+e.point.lat+")";    
            }    
        });    
    function draw(type){    
        drawingManager.open();     
        drawingManager.setDrawingMode(type);    
    }       
            
    function clearAll() {    
        for(var i = 0; i < overlays.length; i++){    
            map.removeOverlay(overlays[i]);    
        }    
        overlays.length = 0       
    }    
    function getPoint(){    
        $("resultShape").innerHTML='';    
        for(var i = 0; i < overlays.length; i++){    
            var overlay=overlays[i].getPath();    
            $("resultShape").innerHTML=$("resultShape").innerHTML+overlay.length+'边形:<br/>';    
            for(var j = 0; j < overlay.length; j++){    
                var grid =overlay[j];    
                $("resultShape").innerHTML=$("resultShape").innerHTML+(j+1)+"个点:("+grid.lng+","+grid.lat+");<br/>";    
            }    
        }    
    }    
    function Editing(state){    
        for(var i = 0; i < overlays.length; i++){    
            state=='enable'?overlays[i].enableEditing():overlays[i].disableEditing();    
        }    
    }    
        
    function  showPolygon(btn){    
      var polygon = new BMap.Polygon([    
          new BMap.Point(113.941853,22.530777),    
          new BMap.Point(113.940487,22.527789),    
          new BMap.Point(113.94788,22.527597),    
          new BMap.Point(113.947925,22.530618)    
      ], styleOptions);  //创建多边形    
      map.addOverlay(polygon);   //增加多边形    
      // overlays.push(polygon); //是否把该图像加入到编辑和删除行列    
       btn.setAttribute('disabled','false');    
       showText();    
     }    
         
     function showText(){    
        var opts = {    
        position : new BMap.Point(113.941853,22.530777),    // 指定文本标注所在的地理位置    
        offset   : new BMap.Size(30, 30)    //设置文本偏移量    
       }    
     var label = new BMap.Label("不可编辑", opts);  // 创建文本标注对象    
        label.setStyle({    
        color : "black",    
         fontSize : "16px",    
        fillColor:"red",      //填充颜色。当参数为空时，圆形将没有填充效果。    
        });    
      map.addOverlay(label);      
     }    
</script>    
</body>    
</html>