nodejs錯(cuò)誤？

const http=require('http');
const fs=require('fs');
var server=http.createServer(function(req,res){
    var file_name='./www'+req.url;
    fs.readFile(file_name,function(err,data){
        if(err){
            res.write('404');
        }else{
            res.write(data);
        }
        res.end();
    })    
})
server.listen(8080);

運(yùn)行上述代碼，出錯(cuò)如下：

events.js:183
      throw er; // Unhandled 'error' event
      ^

Error: listen EADDRINUSE :::8080
    at Object._errnoException (util.js:1024:11)
    at _exceptionWithHostPort (util.js:1046:20)
    at Server.setupListenHandle [as _listen2] (net.js:1351:14)
    at listenInCluster (net.js:1392:12)
    at Server.listen (net.js:1476:7)
    at Object.<anonymous> (E:\Node4\server2.js:14:8)
    at Module._compile (module.js:635:30)
    at Object.Module._extensions..js (module.js:646:10)
    at Module.load (module.js:554:32)
    at tryModuleLoad (module.js:497:12)
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