1.先上匹配算法，通过java的2D画图来实现的，参数为点point，和由N个点组成的List

public static boolean IsPtInPoly(Point2D.Double point, List<Point2D.Double> pts){  
	      
	    int N = pts.size();  
	    boolean boundOrVertex = true; //如果点位于多边形的顶点或边上，也算做点在多边形内，直接返回true  
	    int intersectCount = 0;//cross points count of x   
	    double precision = 2e-10; //浮点类型计算时候与0比较时候的容差  
	    Point2D.Double p1, p2;//neighbour bound vertices  
	    Point2D.Double p = point; //当前点  
	      
	    p1 = pts.get(0);//left vertex          
	    for(int i = 1; i <= N; ++i){//check all rays              
	        if(p.equals(p1)){  
	            return boundOrVertex;//p is an vertex  
	        }  
	          
	        p2 = pts.get(i % N);//right vertex              
	        if(p.x < Math.min(p1.x, p2.x) || p.x > Math.max(p1.x, p2.x)){//ray is outside of our interests                  
	            p1 = p2;   
	            continue;//next ray left point  
	        }  
	          
	        if(p.x > Math.min(p1.x, p2.x) && p.x < Math.max(p1.x, p2.x)){//ray is crossing over by the algorithm (common part of)  
	            if(p.y <= Math.max(p1.y, p2.y)){//x is before of ray                      
	                if(p1.x == p2.x && p.y >= Math.min(p1.y, p2.y)){//overlies on a horizontal ray  
	                    return boundOrVertex;  
	                }  
	                  
	                if(p1.y == p2.y){//ray is vertical                          
	                    if(p1.y == p.y){//overlies on a vertical ray  
	                        return boundOrVertex;  
	                    }else{//before ray  
	                        ++intersectCount;  
	                    }   
	                }else{//cross point on the left side                          
	                    double xinters = (p.x - p1.x) * (p2.y - p1.y) / (p2.x - p1.x) + p1.y;//cross point of y                          
	                    if(Math.abs(p.y - xinters) < precision){//overlies on a ray  
	                        return boundOrVertex;  
	                    }  
	                      
	                    if(p.y < xinters){//before ray  
	                        ++intersectCount;  
	                    }   
	                }  
	            }  
	        }else{//special case when ray is crossing through the vertex                  
	            if(p.x == p2.x && p.y <= p2.y){//p crossing over p2                      
	                Point2D.Double p3 = pts.get((i+1) % N); //next vertex                      
	                if(p.x >= Math.min(p1.x, p3.x) && p.x <= Math.max(p1.x, p3.x)){//p.x lies between p1.x & p3.x  
	                    ++intersectCount;  
	                }else{  
	                    intersectCount += 2;  
	                }  
	            }  
	        }              
	        p1 = p2;//next ray left point  
	    }  
	      
	    if(intersectCount % 2 == 0){//偶数在多边形外  
	        return false;  
	    } else { //奇数在多边形内  
	        return true;  
	    }  
	      
	}  

2.怎么用？调用方法如下：

while((temp1 = br1.readLine()) != null){
    			Point2D.Double point = new Point2D.Double(Double.parseDouble(temp1.split("#")[2].split(",")[0]),Double.parseDouble(temp1.split("#")[2].split(",")[1]));
    			boolean matched = false;
    			for(String key:map.keySet()){
     	 			List<Point2D.Double> polygon = new ArrayList<Point2D.Double>(); //多边形的点
     	 			str1 = map.get(key);
     	 			String[] as = str1.split(",");
     	 			for(int l = 0;l < as.length-1;){
     					Double lont = Double.parseDouble(as[l]);
     					Double latt = Double.parseDouble(as[l+1]);
     					l += 2;
     					Point2D.Double pointt = new Point2D.Double(lont,latt);
     					polygon.add(pointt);
     				}
     				if(IsPtInPoly(point, polygon)){
     					//System.out.println(key+"#"+temp1);
     					bw.write(key+"#"+temp1+"\r\n");
     					matched = true;
     				}
     	 		}
    			if(!matched){
    				System.out.println(temp1);
    			}
    		}