mapperservlet.java

java+mapxtreme 开发校园房管系统

package com.oyc.mapxtreme.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import com.mapinfo.mapj.MapJ;
import com.mapinfo.unit.LinearUnit;
import com.mapinfo.util.DoublePoint;
import com.mapinfo.util.DoubleRect;
import com.oyc.mapxtreme.util.MapConfig;
import com.oyc.mapxtreme.util.RenderMap;

/**
 * servlet:根据客户端Applet的请求生成相应的地图,包括放大处理,缩小处理等
 * @author 三峡大学理学院 欧阳超
 *
 */
public class MapperServlet extends BaseHttpServlet {
	
	//地图属性对象
	private MapConfig mapCfg = MapConfig.getInstance();
	
	//地图的原始视野值
	private double oldZoom;
	
	/**
	 * 全图显示
	 * 
	 */
	public void fullMap(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			//取出MapJ对象,如果不存在,则创建一个
			HttpSession session = request.getSession(true);
			MapJ myMap = (MapJ) session.getAttribute("mapj");
			if (myMap == null) {  //等于null,说明是第一次访问
				//加载地图配置文件
				this.mapCfg.config();
				//初始化地图
				myMap = initMapJ();
			} else {
				myMap.setZoomAndCenter(oldZoom, new DoublePoint(0, 0));
			}
			
			//渲染MapJ,输出
			RenderMap render = new RenderMap();
			render.renderMap(myMap, response);
			
			//将MapJ对象存入Session
			session.setAttribute("mapj", myMap);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * 用放大或缩小按钮单击或拖动Applet中的地图时,缩放地图
	 * 
	 */
	public void zoom(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			//存储Applet传过来的参数
			double ptx = Double.parseDouble(request.getParameter("ptx"));
			double pty = Double.parseDouble(request.getParameter("pty"));
			double zoom = Double.parseDouble(request.getParameter("zoom"));
			
			//取出MapJ对象
			HttpSession session = request.getSession();
			MapJ myMap=(MapJ) session.getAttribute("mapj");
			
			//创建地图中心坐标
			DoublePoint point=new DoublePoint(ptx, pty);
			DoublePoint newpoint=myMap.transformScreenToNumeric(point);
			
			//重置地图视野和中心
			myMap.setZoomAndCenter(zoom, newpoint);
			
			//渲染MapJ,输出
			RenderMap render = new RenderMap();
			render.renderMap(myMap, response);
			
			//将MapJ对象存入Session
			session.setAttribute("mapj", myMap);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * 平移地图
	 * 
	 */
	public void pan(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		try {
			//存储Applet传过来的参数
			double ptx=Double.parseDouble(request.getParameter("ptx"));
			double pty=Double.parseDouble(request.getParameter("pty"));
			
			//取出MapJ对象
			HttpSession session = request.getSession();
			MapJ myMap=(MapJ) session.getAttribute("mapj");
			
			//创建地图中心坐标
			DoublePoint point=new DoublePoint(ptx, pty);
			DoublePoint newpoint=myMap.transformScreenToNumeric(point);
			
			//重置地图中心
			myMap.setCenter(newpoint);
			
			//渲染MapJ,输出
			RenderMap render = new RenderMap();
			render.renderMap(myMap, response);
			
			//将MapJ对象存入Session
			session.setAttribute("mapj", myMap);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	/**
	 * 初始化MapJ
	 * 
	 */
	private MapJ initMapJ() throws Exception {
		MapJ myMap = new MapJ();
		myMap.setDeviceBounds(new DoubleRect(0, 0, this.mapCfg.getMapwidth(), this.mapCfg.getMapheight()));
		
		//加载地图
		try {
			if (this.mapCfg.getFiletoload().endsWith(".gst")) {
				myMap.loadGeoset(this.mapCfg.getFiletoload(), this.mapCfg.getMappath(), null);
			} else {
				myMap.loadMapDefinition(this.mapCfg.getFiletoload());
			}
		} catch (Exception e) {
			System.out.println("Can't load geoset: " + this.mapCfg.getFiletoload() + "\n");
			throw e;
		}
		myMap.setDistanceUnits(LinearUnit.kilometer);
		//记下地图的初始zoom值
		this.oldZoom = myMap.getZoom();
		System.out.println("map old zoom: " + this.oldZoom);
		
		return myMap;
	}

}