Question

在app.js中，我只读取traffic.json文件，但我需要更新traffic.json文件。当我点击提交按钮时，我获取了以前的数据而不是新数据。

Area.html：

var jsonURL = "http://192.168.7.123:3000/traffic";

    d3.json(jsonURL, function(error, data){ 
alert(data);
 ....
 ....
});

app.js：

app.get('/traffic',function(req,res) {
  res.sendfile('views/traffic.json');
});

traffic.json：

[ { "client_ip" : "1.0.230.145" , "timestamp" : "1341667450773" , "total_traffic" : 0} , { "client_ip" : "1.0.230.145" , "timestamp" : "1341667450786" , "total_traffic" : 3} , { "client_ip" : "1.0.230.145" , "timestamp" : "1341667451076" , "total_traffic" : 4} , { "client_ip" : "1.0.230.145" , "timestamp" : "1341667451104" , "total_traffic" : 7} , { "client_ip" : "1.0.230.145" , "timestamp" : "1341667451128" , "total_traffic" : 10}]

如何更新traffic.json文件，以便在点击提交后获取新更新的数据？

Answer 1

您可JSON.stingify()使用fs.writeFile()或fs.writeFileSync()

将traffic.json新数据保存到

var fs = require('fs');

app.get('/traffic',function(req,res) {
  // I don't know what information you need to save. IP of the client that clicked button?
  fs.writeFileSync('views/traffic.json', JSON.stringify(newData)); 
  res.sendfile('views/traffic.json');
});

<form-login login-page="/redirect" 
        login-processing-url="/submitLogin" 
        username-parameter="j_username" 
        password-parameter="j_password" 
        authentication-failure-handler-ref="loginFailureHandler" 
        authentication-success-handler-ref="loginSuccessHandler" />

 <authentication-manager>
    <authentication-provider>
        <jdbc-user-service 
            data-source-ref="sybaseDataSource" 
            users-by-username-query="SELECT distinct EnterpriseID as username, 'password' as password, 1 as enabled FROM users where id = ?" 
            authorities-by-username-query="SELECT ? as id, 'ROLE_USER' as authority" 
           <!-- I know, it shouldnt be like this, just for the sake of the user having an authority -->
        />
    </authentication-provider>
</authentication-manager>

如何在node.js中读取JSON文件后更新它

1 个答案: