在thinkphp的公共目录的config配置文件中增加配置项:
 
'TMPL_EXCEPTION_FILE' => 'Public/404.html',
在Public文件夹中创建404.html内容如下
<!DOCTYPE html >
<html>
<head>
<meta charset=utf-8" />
<title>404哟</title>
<style type="text/css">
body {
  background-color: #ECECEC;
  font-family: 'Open Sans', sans-serif;
  font-size: 14px;
  color: #3c3c3c;
}
.demo{width:600px;margin:0 auto;}
.demo p:first-child {
  text-align: center;
  font-family: cursive;
  font-size: 150px;
  font-weight: bold;
  line-height: 100px;
  letter-spacing: 5px;
  color: #fff;
}
.demo p:first-child span {
cursor: pointer;
  text-shadow: 0px 0px 2px #686868, 0px 1px 1px #ddd,
 0px 2px 1px #d6d6d6,
    0px 3px 1px #ccc,
    0px 4px 1px #c5c5c5,
    0px 5px 1px #c1c1c1,
    0px 6px 1px #bbb,
    0px 7px 1px #777,
    0px 8px 3px rgba(100, 100, 100, 0.4),
    0px 9px 5px rgba(100, 100, 100, 0.1),
    0px 10px 7px rgba(100, 100, 100, 0.15),
    0px 11px 9px rgba(100, 100, 100, 0.2),
    0px 12px 11px rgba(100, 100, 100, 0.25),
    0px 13px 15px rgba(100, 100, 100, 0.3);
  -webkit-transition: all .1s linear;
  transition: all .1s linear;
}
.demo p:first-child span:hover {
  text-shadow: 0px 0px 2px #686868,
    0px 1px 1px #fff,
    0px 2px 1px #fff,
    0px 3px 1px #fff,
    0px 4px 1px #fff,
    0px 5px 1px #fff,
    0px 6px 1px #fff,
    0px 7px 1px #777,
    0px 8px 3px #fff,
    0px 9px 5px #fff,
    0px 10px 7px #fff,
    0px 11px 9px #fff,
    0px 12px 11px #fff,
    0px 13px 15px #fff;
  -webkit-transition: all .1s linear;
  transition: all .1s linear;
}
.demo p:not(:first-child) {
  text-align: center;
  color: #666;
  font-family: cursive;
  font-size: 20px;
  text-shadow: 0 1px 0 #fff;
  letter-spacing: 1px;
  line-height: 2em;
  margin-top: -50px;
}
</style>
<script type="text/javascript">    
function countDown(secs,surl){    
    var jumpTo = document.getElementById('jumpTo');
    jumpTo.innerHTML=secs; 
    if(--secs>0){    
        setTimeout("countDown("+secs+",'"+surl+"')",1000);    
     }    
    else{      
        location.href=surl;    
    }    
}    
</script>
</head>
<body>
<div class="demo">
    <p><span>4</span><span>0</span><span>4</span></p>
    <p>该页面不存在(′?ω?`)<span id="jumpTo">5</span>秒后跳转到首页</p>
</div>
<script type="text/javascript">
    countDown(5,'/');
</script>
</body>
</html>
这样就完成了,至于状态码当然是 404了,因为thinkphp默认不存在的页面返回404,大功告成