淘忆项目之主页界面服务器端的修正归纳

淘忆项目之主页界面服务器端的修正归纳
服务器端需要传递给客户端信息，传给的数据有用户的头像和名字，物件的图片，发布时间，收藏的数量，留言的数量。
采用mvc
模式书写服务器端的代码。
第一步：建立以下文件。
建立三个包，三个文件。 
第二步：书写HomeItemService.java的内容。
package com.elaine.homeItem.service;
 
import java.util.List;
import java.util.Map;
 
public interface HomeItemService {
public List<Map<String, Object>> listThing();
}
第三步：书写HomeItemDao.java的内容。
package com.elaine.homeItem.dao;
 
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
 
import com.elaine.homeItem.service.HomeItemService;
import com.elaine.jdbc.JdbcUtils;
 
public class HomeItemDao implements HomeItemService{
JdbcUtils jdbcUtils;
 
public HomeItemDao() {
// TODO Auto-generated constructor stub
jdbcUtils=new JdbcUtils();
}
 
@Override
public List<Map<String, Object>> listThing() {
// TODO Auto-generated method stub
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
try {
jdbcUtils.getConnection();
String lineSql="select * from thingInfo"; //首先获取所有的物件的信息
int lineNum=jdbcUtils.getLineNum(lineSql);//获取一共有多少行的行数
for(int id=1;id<=lineNum;id++){
String sql="select * from thingInfo where (1=1)";
StringBuffer buffer = new StringBuffer(sql);
List<Object> params = new ArrayList<Object>();
buffer.append("and  id like ?");
params.add("%" + id + "%");
Map<String, Object> map=jdbcUtils.findSimpleResult(buffer.toString(), params);
String userId=(String) map.get("userId");
String userSql="select *from userInfo where userId=?"; //获取user的信息
List<Object> params1=new ArrayList<Object>();
params1.add(userId);
Map<String, Object> map1 = jdbcUtils.findSimpleResult(userSql, params1);
String username=(String) map1.get("username");
String userHead=(String) map1.get("userHead");
map.put("username", username);
map.put("userHead", userHead);//将姓名和头像的图片地址传给map
list.add(map);
}

} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
} finally {
jdbcUtils.releaseConn();
}
 
return list;
}
 
}
第四步:书写HomeItemAction.java的内容。
package com.elaine.homeItem.action;
 
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
import java.util.Map;
 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
import com.elaine.homeItem.dao.HomeItemDao;
import com.elaine.homeItem.service.HomeItemService;
import com.elaine.tools.jsonTool;
 
 
public class HomeItemAction extends HttpServlet {
 
/**
 *
 */
private static final long serialVersionUID = 1L;
private HomeItemService service;
/**
 * Constructor of the object.
 */
public HomeItemAction() {
super();
}
 
/**
 * Destruction of the servlet. <br>
 */
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
 
/**
 * The doGet method of the servlet. <br>
 *
 * This method is called when a form has its tag value method equals to get.
 *
 * @param request the request send by the client to the server
 * @param response the response send by the server to the client
 * @throws ServletException if an error occurred
 * @throws IOException if an error occurred
 */
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
 
this.doPost(request, response);
}
 
/**
 * The doPost method of the servlet. <br>
 *
 * This method is called when a form has its tag value method equals to post.
 *
 * @param request the request send by the client to the server
 * @param response the response send by the server to the client
 * @throws ServletException if an error occurred
 * @throws IOException if an error occurred
 */
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out = response.getWriter();
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
List<Map<String, Object>> list = service.listThing();
String jsonString = jsonTool.creataJsonString("thing", list);
out.print(jsonString);
out.flush();
out.close();
}
 
/**
 * Initialization of the servlet. <br>
 *
 * @throws ServletException if an error occurs
 */
public void init() throws ServletException {
// Put your code here
service=new HomeItemDao();
}
 
}
经过以上的三步就可以向客户端传递需要的数据了。