最近在学Json,在网上也找过一些资料，觉得有点乱，在这里，我以easy ui的登录界面为例来说一下怎样用Json实现前后台的数据交互

使用Json,首先需要导入一些jar包，这些资源可以在网上下载到，然后导入到项目中即可。

首先我先把代码贴出来，有些地方会着重说明一下：

客户端代码如下：

<%@page pageEncoding="utf-8"%>    
          
      
        

password:$('#loginInputForm input[name=password]').val()                                 },                          dataType:'json',//接收的数据为json格式，这里还有其他方法，可以看我关于Json解析的那篇文章                          success:function(data){   //Json为返回的Json对象，名字自己起                             $.messager.alert('通知',data.msg);                                    },                           error:function(){                           $.messager.alert('通知',"错误");                                 }                           });                                      }},{       //handler:按钮的点击事件                 text:'注册',                 handler:function(){                                                     }}]     });  });             
    
    
     
     
      
                 
        
                     
用户名
                     
                  
                  
                     
密  码
                     
                  
            
      
         
     
   
    
  

服务器端代码如下：

package thejavabean;import java.io.IOException;import java.io.PrintWriter;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import net.sf.json.JSONObject;public class UserContro extends HttpServlet {	public void doGet(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {         	request.setCharacterEncoding("UTF-8");  //接收数据的编码格式	        response.setCharacterEncoding("UTF-8"); //返回数据的编码格式为utf-8,防止客户端乱码 		response.setContentType("text/json");    		PrintWriter out = response.getWriter();		String name=request.getParameter("name");//接收数据

String password=request.getParameter("password");		String msg="";		JSONObject  jobj = new JSONObject();//把要传向客户端的数据转为Json字符串

jobj.put("msg",login(name,password));

response.getWriter().write(jobj.toString());//向客户端返回数据	    		out.flush();		out.close();		}	public String login(String name,String password){	    User user=new User();	    user.setName(name);	    user.setPassword(password);	   	try {			if(user.login()!=null)			 	return "登录成功";			 else 			    return "用户名或密码错误";		} catch (SQLException e) {			e.printStackTrace();		}    	   	return null;	 }	 */	public void doPost(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {	}}

User 类

public class User {     private String name;     private String password;  	public String getName() {		return name;	}	public void setName(String name) {		this.name = name;	}	public String getPassword() {		return password;	}	public void setPassword(String password) {		this.password = password;	}     DBConnection dbc=new DBConnection();	//用户登录	public User login() throws SQLException{		Connection conn=null;		PreparedStatement ps=null;		ResultSet rs;		User user=null;		try{		conn=dbc.getConnection();		String sql="select * from [user] where name=? and password=?";		ps=conn.prepareStatement(sql);		ps.setString(1,name);		ps.setString(2,password);		rs=ps.executeQuery();		if(rs.next()){			user=new User();			user.setName(rs.getString("name"));			user.setPassword("password");		}		}finally{		ps.close();		conn.close();		}		return user;	}

简单封装的DB:

public class DBConnection {   private  String user="sa";   private  String password="aaaaaa";   private  String url="jdbc:sqlserver://localhost:1433;DatabaseName=team";   private static String driverName = "com.microsoft.sqlserver.jdbc.SQLServerDriver";   Connection conn;   PreparedStatement ps;   ResultSet rs;         static{	try {		Class.forName(driverName);	} catch (ClassNotFoundException e) {	     System.out.println("驱动加载失败");	}   }      public  Connection getConnection() throws SQLException{   		conn=DriverManager.getConnection(url,user,password);	     return conn;   }  }