Servlet 返回Json数据格式

其实就是把数据库中的数据查询出来拼接成一个Json数据

 import dao.UserDao;
 import endy.User;

 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.util.List;

 @WebServlet("/Json")
 public class Json extends HttpServlet {
     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

     }

     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         UserDao ud=new UserDao();
         List<User> users=ud.FandAll();
         response.setCharacterEncoding("utf-8");
         response.setContentType("application/json;charset=utf-8");
         PrintWriter out=response.getWriter();
         String[] keys={"id","name","pwd","phone","img"};//属性名称
         StringBuffer json=new StringBuffer("[");
         for (int i=0;i<users.size();i++){
             json.append("{");
             User u=users.get(i);
             Object[] values=u.toarry();
             for (int j=0;j<keys.length;j++){
                 json.append("\""+keys[j]+"\":\""+values[j]+"\"");
                 if (j<keys.length-1) json.append(",");
             }
             json.append("}");
             if (i<users.size()-1) json.append(",");
         }
         json.append("]");
         out.write(json.toString());
         out.close();
     }
 }

这里是后台直接拼成json字符串

26         StringBuffer json=new StringBuffer("[");
27         for (int i=0;i<users.size();i++){
28             json.append("{");
29             User u=users.get(i);
30             Object[] values=u.toarry();
31             for (int j=0;j<keys.length;j++){
32                 json.append("\""+keys[j]+"\":\""+values[j]+"\"");
33                 if (j<keys.length-1) json.append(",");
34             }
35             json.append("}");
36             if (i<users.size()-1) json.append(",");
37         }
38         json.append("]");