blocks|key|635449|text|我发现这个例子很有帮助：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635450|https://github.com/visionmedia/express/blob/master/examples/error-pages/index.js|offset|length|635451|所以，它实际上是这一部分：|635452|//+"app.router"+positions+our+routes
//+above+the+middleware+defined+below,
//+this+means+that+Express+will+attempt
//+to+match+&+call+routes+_before_+continuing
//+on,+at+which+point+we+assume+it's+a+404+because
//+no+route+has+handled+the+request.

app.use(app.router);

//+Since+this+is+the+last+non-error-handling
//+middleware+use()d,+we+assume+404,+as+nothing+else
//+responded.

//+$+curl+http://localhost:3000/notfound
//+$+curl+http://localhost:3000/notfound+-H+"Accept:+application/json"
//+$+curl+http://localhost:3000/notfound+-H+"Accept:+text/plain"

app.use(function(req,+res,+next)+{
++res.status(404);

++//+respond+with+html+page
++if+(req.accepts('html'))+{
++++res.render('404',+{+url:+req.url+});
++++return;
++}

++//+respond+with+json
++if+(req.accepts('json'))+{
++++res.json({+error:+'Not+found'+});
++++return;
++}

++//+default+to+plain-text.+send()
++res.type('txt').send('Not+found');
});|code-block|syntax|javascript|635453|entityMap|0|LINK|mutability|MUTABLE|url^0|0|0|28|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@$D|V|E|W|1|X]]|A|$]]|$1|F|3|G|5|6|7|Y|8|@]|9|@]|A|$]]|$1|H|3|I|5|J|7|Z|8|@]|9|@]|A|$K|L]]|$1|M|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|C]]]]

I found this example quite helpful:
<a href="https://github.com/visionmedia/express/blob/master/examples/error-pages/index.js" rel="noreferrer">https://github.com/visionmedia/express/blob/master/examples/error-pages/index.js</a>
So, it is actually this part:
<pre><code>// &quot;app.router&quot; positions our routes
// above the middleware defined below,
// this means that Express will attempt
// to match &amp; call routes _before_ continuing
// on, at which point we assume it's a 404 because
// no route has handled the request.

app.use(app.router);

// Since this is the last non-error-handling
// middleware use()d, we assume 404, as nothing else
// responded.

// $ curl http://localhost:3000/notfound
// $ curl http://localhost:3000/notfound -H &quot;Accept: application/json&quot;
// $ curl http://localhost:3000/notfound -H &quot;Accept: text/plain&quot;

app.use(function(req, res, next) {
 res.status(404);

 // respond with html page
 if (req.accepts('html')) {
 res.render('404', { url: req.url });
 return;
 }

 // respond with json
 if (req.accepts('json')) {
 res.json({ error: 'Not found' });
 return;
 }

 // default to plain-text. send()
 res.type('txt').send('Not found');
});
</code></pre>

blocks|key|635397|text|您可以将中间件放在抛出NotFound错误的最后位置，|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|635398|或者甚至直接呈现404页面：|635399|app.use(function(req,res){
++++res.status(404).render('404.jade');
});|code-block|syntax|javascript|635400|entityMap^0|B|8|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|R|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|S|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|N|$]]

You can put a middleware at the last position that throws a <code>NotFound</code> error, 
or even renders the 404 page directly:

<pre><code>app.use(function(req,res){
 res.status(404).render('404.jade');
});
</code></pre>

blocks|key|635623|text|以上答案都很好，但其中一半不会返回404作为HTTP状态码，而另一半则不能进行自定义模板呈现。在Expressjs中创建自定义错误页面(404)的最好方法是|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635624|app.use(function(req,+res,+next){
++++res.status(404).render('404_error_template',+{title:+"Sorry,+page+not+found"});
});|code-block|syntax|javascript|635625|将此代码放在所有URL映射的末尾。|635626|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

The above answers are good, but in half of these you won't be getting 404 as your HTTP status code returned and in other half, you won't be able to have a custom template render. The best way to have a custom error page (404's) in Expressjs is

<pre><code>app.use(function(req, res, next){
 res.status(404).render('404_error_template', {title: "Sorry, page not found"});
});
</code></pre>

Place this code at the end of all your URL mappings.

blocks|key|635559|text|在app.js的最后一行，只需放入此函数。这将覆盖默认的页面找不到错误页面：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635560|app.use(function+(req,+res)+{
++++res.status(404).render('error');
});|code-block|syntax|javascript|635561|它将覆盖所有没有有效处理程序的请求，并呈现您自己的错误页面。|635562|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

At the last line of app.js just put this function. This will override the default page-not-found error page:

<pre><code>app.use(function (req, res) {
 res.status(404).render('error');
});
</code></pre>

It will override all the requests that don't have a valid handler and render your own error page.

blocks|key|852054|text|你的问题的答案是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852055|app.use(function(req,+res)+{
++++res.status(404).end('error');
});|code-block|syntax|javascript|852056|有一篇很棒的文章解释了为什么它是最好的here方式。|offset|length|852057|entityMap|0|LINK|mutability|MUTABLE|url|http://www.hacksparrow.com/express-js-custom-error-pages-404-and-500.html^0|0|0|J|4|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

The answer to your question is:

<pre><code>app.use(function(req, res) {
 res.status(404).end('error');
});
</code></pre>

And there is a great article about why it is the best way <a href="http://www.hacksparrow.com/express-js-custom-error-pages-404-and-500.html" rel="noreferrer">here</a>.

blocks|key|852109|text|express-error-handler允许您为错误指定自定义模板、静态页面或错误处理程序。它还做了其他有用的错误处理，这是每个应用程序都应该实现的，比如防止4xx错误DOS攻击，以及在不可恢复的错误上正常关闭。下面是你是如何做到你所要求的：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|852110|var+errorHandler+=+require('express-error-handler'),
++handler+=+errorHandler({
++++static:+{
++++++'404':+'path/to/static/404.html'
++++}
++});

//+After+all+your+routes...
//+Pass+a+404+into+next(err)
app.use(+errorHandler.httpError(404)+);

//+Handle+all+unhandled+errors:
app.use(+handler+);|code-block|syntax|javascript|852111|或者对于自定义处理程序：|852112|handler+=+errorHandler({
++handlers:+{
++++'404':+function+err404()+{
++++++//+do+some+custom+thing+here...
++++}
++}
});+|852113|或者用于自定义视图：|852114|handler+=+errorHandler({
++views:+{
++++'404':+'404.jade'
++}
});|852115|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/dilvie/express-error-handler^0|0|L|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@$A|Z|B|10|1|11]]|C|$]]|$1|D|3|E|5|F|7|12|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|13|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|15|8|@]|9|@]|C|$]]|$1|O|3|P|5|F|7|16|8|@]|9|@]|C|$G|H]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]]]

<a href="https://github.com/dilvie/express-error-handler" rel="nofollow">express-error-handler</a> lets you specify custom templates, static pages, or error handlers for your errors. It also does other useful error-handling things that every app should implement, like protect against 4xx error DOS attacks, and graceful shutdown on unrecoverable errors. Here's how you do what you're asking for:

<pre><code>var errorHandler = require('express-error-handler'),
 handler = errorHandler({
 static: {
 '404': 'path/to/static/404.html'
 }
 });

// After all your routes...
// Pass a 404 into next(err)
app.use( errorHandler.httpError(404) );

// Handle all unhandled errors:
app.use( handler );
</code></pre>

Or for a custom handler:

<pre><code>handler = errorHandler({
 handlers: {
 '404': function err404() {
 // do some custom thing here...
 }
 }
}); 
</code></pre>

Or for a custom view:

<pre><code>handler = errorHandler({
 views: {
 '404': '404.jade'
 }
});
</code></pre>

blocks|key|852153|text|在某些情况下，404页面不能作为最后一个路由执行，特别是如果您有一个异步路由功能，它会在聚会中引入一个较晚的/route。在这些情况下，可以采用下面的模式。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852154|var+express+=+require("express.io"),
++++app+=+express(),
++++router+=+express.Router();

router.get("/hello",+function+(req,+res)+{
++++res.send("Hello+World");
});

//+Router+is+up+here.
app.use(router);

app.use(function(req,+res)+{
++++res.send("Crime+Scene+404.+Do+not+repeat");
});

router.get("/late",+function+(req,+res)+{
++++res.send("Its+OK+to+come+late");
});

app.listen(8080,+function+(){
++++console.log("Ready");
});|code-block|syntax|javascript|852155|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

There are some cases where 404 page cannot be written to be executed as the last route, especially if you have an asynchronous routing function that brings in a /route late to the party. The pattern below might be adopted in those cases. 

<pre><code>var express = require("express.io"),
 app = express(),
 router = express.Router();

router.get("/hello", function (req, res) {
 res.send("Hello World");
});

// Router is up here.
app.use(router);

app.use(function(req, res) {
 res.send("Crime Scene 404. Do not repeat");
});

router.get("/late", function (req, res) {
 res.send("Its OK to come late");
});

app.listen(8080, function (){
 console.log("Ready");
});
</code></pre>

blocks|key|851691|text|https://github.com/robrighter/node-boilerplate/blob/master/templates/app/server.js|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|851692|这就是node-boilerplate所做的。|851693|entityMap|0|LINK|mutability|MUTABLE|url^0|0|2A|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@$A|N|B|O|1|P]]|C|$]]|$1|D|3|E|5|6|7|Q|8|@]|9|@]|C|$]]|$1|F|3|-4|5|6|7|R|8|@]|9|@]|C|$]]]|G|$H|$5|I|J|K|C|$L|4]]]]

<a href="https://github.com/robrighter/node-boilerplate/blob/master/templates/app/server.js" rel="nofollow">https://github.com/robrighter/node-boilerplate/blob/master/templates/app/server.js</a>

This is what node-boilerplate does.

blocks|key|635966|text|嗨，请找出答案|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635967|const+express+=+require('express');
const+app+=+express();
const+port+=+8080;

app.get('/',+(req,+res)+=>+res.send('Hello+home!'));
app.get('/about-us',+(req,+res)+=>+res.send('Hello+about+us!'));
app.post('/user/set-profile',+(req,+res)+=>+res.send('Hello+profile!'));
//last+404+page+
app.get('*',+(req,+res)+=>+res.send('Page+Not+found+404'));
app.listen(port,+()+=>+console.log(`Example+app+listening+on+port+${port}!`));|code-block|syntax|javascript|635968|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Hi please find the answer

<pre><code>const express = require('express');
const app = express();
const port = 8080;

app.get('/', (req, res) =&gt; res.send('Hello home!'));
app.get('/about-us', (req, res) =&gt; res.send('Hello about us!'));
app.post('/user/set-profile', (req, res) =&gt; res.send('Hello profile!'));
//last 404 page 
app.get('*', (req, res) =&gt; res.send('Page Not found 404'));
app.listen(port, () =&gt; console.log(`Example app listening on port ${port}!`));
</code></pre>

blocks|key|635811|text|//+Add+this+middleware
//+error+handler
app.use(function(err,+req,+res,+next)+{
+//+set+locals,+only+providing+error+in+development
+++res.locals.message+=+err.message;
+++res.locals.error+=+req.app.get('env')+===+'development'+?+err+:+{};

+//+render+the+error+page
+++res.status(err.status+%7C%7C+500);
+++res.render('error');
++});|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|635812|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>// Add this middleware
// error handler
app.use(function(err, req, res, next) {
 // set locals, only providing error in development
 res.locals.message = err.message;
 res.locals.error = req.app.get('env') === 'development' ? err : {};

 // render the error page
 res.status(err.status || 500);
 res.render('error');
 });
</code></pre>

blocks|key|852354|text|要做到这一点，最简单的方法是创建一个catch+all+for+Error页面|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852355|//+Step+1:+calling+express
const+express+=+require("express");
const+app+=+express();|code-block|syntax|javascript|852356|然后|852357|//+require+Path+to+get+file+locations
const+path+=+require("path");|852358|现在，您可以将所有的"html“页面(包括错误的"html”页面)存储在一个变量中|852359|//+Storing+file+locations+in+a+variable
var+indexPg+=+path.join(__dirname,+"./htmlPages/index.html");
var+aboutPg+=+path.join(__dirname,+"./htmlPages/about.html");
var+contactPg+=+path.join(__dirname,+"./htmlPages/contact.html");
var+errorPg+=+path.join(__dirname,+"./htmlPages/404.html");+//this+is+your+error+page|852360|现在，您只需使用Get方法调用页面，并使用app.get("*")将所有不可用的路由捕获到错误页面。|852361|//Step+2:+Defining+Routes
//default+page+will+be+your+index.html
app.get("/",+function(req,res){
++res.sendFile(indexPg);
});
//about+page
app.get("/about",+function(req,res){
++res.sendFile(aboutPg);
});
//contact+page
app.get("/contact",+function(req,res){
++res.sendFile(contactPg);
});
//catch+all+endpoint+will+be+Error+Page
app.get("*",+function(req,res){
++res.sendFile(errorPg);
});|852362|别忘了设置一个端口并监听服务器：|852363|//+Setting+port+to+listen+on
const+port+=+process.env.PORT+%7C%7C+8000;
//+Listening+on+port
app.listen(port,+function(){
++console.log(`http://localhost:${port}`);
})|852364|现在应该会为所有无法识别的端点显示错误页面！|852365|entityMap^0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|11|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|12|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|13|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|14|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|15|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|16|8|@]|9|@]|A|$]]|$1|Q|3|R|5|D|7|17|8|@]|9|@]|A|$E|F]]|$1|S|3|T|5|6|7|18|8|@]|9|@]|A|$]]|$1|U|3|V|5|D|7|19|8|@]|9|@]|A|$E|F]]|$1|W|3|X|5|6|7|1A|8|@]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]]|Z|$]]

The easiest way to do it is to have a catch all for Error Page

<pre><code>// Step 1: calling express
const express = require("express");
const app = express();
</code></pre>

Then

<pre><code>// require Path to get file locations
const path = require("path");
</code></pre>

Now you can store all your "html" pages (including an error "html" page) in a variable

<pre><code>// Storing file locations in a variable
var indexPg = path.join(__dirname, "./htmlPages/index.html");
var aboutPg = path.join(__dirname, "./htmlPages/about.html");
var contactPg = path.join(__dirname, "./htmlPages/contact.html");
var errorPg = path.join(__dirname, "./htmlPages/404.html"); //this is your error page
</code></pre>

Now you simply call the pages using the Get Method and have a catch all for any routes not available to direct to your error page using app.get("*")

<pre><code>//Step 2: Defining Routes
//default page will be your index.html
app.get("/", function(req,res){
 res.sendFile(indexPg);
});
//about page
app.get("/about", function(req,res){
 res.sendFile(aboutPg);
});
//contact page
app.get("/contact", function(req,res){
 res.sendFile(contactPg);
});
//catch all endpoint will be Error Page
app.get("*", function(req,res){
 res.sendFile(errorPg);
});
</code></pre>

Don't forget to set up a Port and Listen for server:

<pre><code>// Setting port to listen on
const port = process.env.PORT || 8000;
// Listening on port
app.listen(port, function(){
 console.log(`http://localhost:${port}`);
})
</code></pre>

This should now show your error page for all unrecognized endpoints!

blocks|key|636119|text|express中所有超文本传输协议动词的覆盖|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|636120|为了涵盖all+HTTP+verbs和所有剩余路径，您可以使用：|636121|app.all('*',+cb)|code-block|syntax|javascript|636122|636123|最终解决方案将如下所示：|636124|app.all('*',+(req,+res)+=>{
++++res.status(404).json({
++++++++success:+false,
++++++++data:+'404'
++++})
})|636125|你不应该忘记把路由器放在最后。因为路由器的顺序很重要。|636126|entityMap|0|LINK|mutability|MUTABLE|url|https://expressjs.com/ru/api.html#app.all^0|0|7|0|4|E|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@]|D|@$9|15|A|16|1|17]]|E|$]]|$1|H|3|I|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|19|8|@]|D|@]|E|$]]|$1|N|3|O|5|6|7|1A|8|@]|D|@]|E|$]]|$1|P|3|Q|5|J|7|1B|8|@]|D|@]|E|$K|L]]|$1|R|3|S|5|6|7|1C|8|@]|D|@]|E|$]]|$1|T|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|U|$V|$5|W|X|Y|E|$Z|10]]]]

<h2>Covering of all HTTP verbs in <code>express</code></h2>
In order to cover <a href="https://expressjs.com/ru/api.html#app.all" rel="nofollow noreferrer">all HTTP verbs</a> and all remaining paths you could use:
<pre><code>app.all('*', cb)
</code></pre>
<hr />
Final solution would look like so:
<pre><code>app.all('*', (req, res) =&gt;{
 res.status(404).json({
 success: false,
 data: '404'
 })
})
</code></pre>
You shouldn't forget to put the router in the end.
Because order of routers matter.

blocks|key|635502|text|虽然上面的答案是正确的，但是对于那些想要在IISNODE中使用它的人，您还需要指定|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635503|<configuration>
++++<system.webServer>
++++++++<httpErrors+existingResponse="PassThrough"/>
++++</system.webServer>
<configuration>|code-block|syntax|javascript|635504|在你的web.config中(否则IIS会吃掉你的输出)。|635505|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

While the answers above are correct, for those who want to get this working in IISNODE you also need to specify 

<pre><code>&lt;configuration&gt;
 &lt;system.webServer&gt;
 &lt;httpErrors existingResponse="PassThrough"/&gt;
 &lt;/system.webServer&gt;
&lt;configuration&gt;
</code></pre>

in your web.config (otherwise IIS will eat your output).

blocks|key|635861|text|您可以根据内容类型进行错误处理|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635862|另外，根据状态码进行处理。|635863|app.js|offset|length|style|CODE|635864|import+express+from+'express';

//+catch+404+and+forward+to+error+handler
app.use(function(req,+res,+next)+{
++var+err+=+new+Error('Not+Found');
++err.status+=+404;
++next(err);
});

//+when+status+is+404,+error+handler
app.use(function(err,+req,+res,+next)+{
++++//+set+locals,+only+providing+error+in+development
++++res.locals.message+=+err.message;
++++res.locals.error+=+req.app.get('env')+===+'development'+?+err+:+{};

++++//+render+the+error+page
++++res.status(err.status+%7C%7C+500);
++++if(+404+===+err.status++){
++++++++res.format({
++++++++++++'text/plain':+()+=>+{
++++++++++++++++res.send({message:+'not+found+Data'});
++++++++++++},
++++++++++++'text/html':+()+=>+{
++++++++++++++++res.render('404.jade');
++++++++++++},
++++++++++++'application/json':+()+=>+{
++++++++++++++++res.send({message:+'not+found+Data'});
++++++++++++},
++++++++++++'default':+()+=>+{
++++++++++++++++res.status(406).send('Not+Acceptable');
++++++++++++}
++++++++})
++++}

++++//+when+status+is+500,+error+handler
++++if(500+===+err.status)+{
++++++++return+res.send({message:+'error+occur'});
++++}
});|code-block|syntax|javascript|635865|404.jade|635866|doctype+html

html
++head
++++title+404+Not+Found

++++meta(http-equiv="Content-Type"+content="text/html;+charset=utf-8")
++++meta(name+=+"viewport"+content="width=device-width,+initial-scale=1.0+user-scalable=no")

++body
++++++h2+Not+Found+Page
++++++h2+404+Error+Code|635867|如果可以使用res.format，则可以编写简单的错误处理代码。|635868|建议使用res.format()而不是res.accepts()。|635869|如果前面的代码中出现500错误，则调用if(500+==+err.status){.+.+.+}|635870|entityMap^0|0|0|0|6|0|0|0|8|0|0|0|4|C|J|D|0|J|T|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|12|8|@$F|13|G|14|H|I]]|9|@]|A|$]]|$1|J|3|K|5|L|7|15|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|16|8|@$F|17|G|18|H|I]]|9|@]|A|$]]|$1|Q|3|R|5|L|7|19|8|@]|9|@]|A|$M|N]]|$1|S|3|T|5|6|7|1A|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1B|8|@$F|1C|G|1D|H|I]|$F|1E|G|1F|H|I]]|9|@]|A|$]]|$1|W|3|X|5|6|7|1G|8|@$F|1H|G|1I|H|I]]|9|@]|A|$]]|$1|Y|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|Z|$]]

you can error handling according to content-type 

Additionally, handling according to status code.

<code>app.js</code>

<pre><code>import express from 'express';

// catch 404 and forward to error handler
app.use(function(req, res, next) {
 var err = new Error('Not Found');
 err.status = 404;
 next(err);
});

// when status is 404, error handler
app.use(function(err, req, res, next) {
 // set locals, only providing error in development
 res.locals.message = err.message;
 res.locals.error = req.app.get('env') === 'development' ? err : {};

 // render the error page
 res.status(err.status || 500);
 if( 404 === err.status ){
 res.format({
 'text/plain': () =&gt; {
 res.send({message: 'not found Data'});
 },
 'text/html': () =&gt; {
 res.render('404.jade');
 },
 'application/json': () =&gt; {
 res.send({message: 'not found Data'});
 },
 'default': () =&gt; {
 res.status(406).send('Not Acceptable');
 }
 })
 }

 // when status is 500, error handler
 if(500 === err.status) {
 return res.send({message: 'error occur'});
 }
});
</code></pre>

<code>404.jade</code>

<pre><code>doctype html

html
 head
 title 404 Not Found

 meta(http-equiv="Content-Type" content="text/html; charset=utf-8")
 meta(name = "viewport" content="width=device-width, initial-scale=1.0 user-scalable=no")

 body
 h2 Not Found Page
 h2 404 Error Code
</code></pre>

If you can using res.format, You can write simple error handling code.

Recommendation <code>res.format()</code> instead of <code>res.accepts()</code>.

If the 500 error occurs in the previous code, <code>if(500 == err.status){. . . }</code> is called

blocks|key|636212|text|上面的代码对我不起作用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|636213|所以我找到了一个实际有效的新解决方案！|636214|app.use(function(req,+res,+next)+{
++++res.status(404).send('Unable+to+find+the+requested+resource!');
});|code-block|syntax|javascript|636215|或者，您甚至可以将其呈现为一个404页面。|636216|app.use(function(req,+res,+next)+{
++++res.status(404).render("404page");
});|636217|希望这对你有帮助！|636218|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|V|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

The above code didn't work for me.
So I found a new solution that actually works!
<pre><code>app.use(function(req, res, next) {
 res.status(404).send('Unable to find the requested resource!');
});
</code></pre>
Or you can even render it to a 404 page.
<pre><code>app.use(function(req, res, next) {
 res.status(404).render(&quot;404page&quot;);
});
</code></pre>
Hope this helped you!

blocks|key|852188|text|如果你使用快速生成器包：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852189|next(错误)；|852190|这段代码会将您发送到404中间件。|852191|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

If you use express-generator package: 

next(err);

This code send you to the 404 middleware.

blocks|key|635785|text|要发送到自定义页面，请执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|635786|app.get('*',+function(req,+res){
++if+(req.accepts('html'))+{
+++++res.send('404',+'<script>location.href+=+"/the-404-page.html";</script>');
+++++return;
++}
});|code-block|syntax|javascript|635787|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

To send to a custom page:

<pre><code>app.get('*', function(req, res){
 if (req.accepts('html')) {
 res.send('404', '&lt;script&gt;location.href = "/the-404-page.html";&lt;/script&gt;');
 return;
 }
});
</code></pre>

blocks|key|852467|text|应该在对app.listen.Express的调用支持路由路径中的*之前设置404页面。这是一个特殊的字符，可以匹配任何内容。这可用于创建匹配所有请求的路由处理程序。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852468|app.get('*',+(req,+res)+=>+{
++res.render('404',+{
++++title:+'404',
++++name:+'test',
++++errorMessage:+'Page+not+found.'
++})
})|code-block|syntax|javascript|852469|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

The 404 page should be set up just before the call to app.listen.Express has support for * in route paths. This is a special character which matches
anything. This can be used to create a route handler that matches all requests.

<pre><code>app.get('*', (req, res) =&gt; {
 res.render('404', {
 title: '404',
 name: 'test',
 errorMessage: 'Page not found.'
 })
})
</code></pre>

blocks|key|636274|text|定义完所有路由后，我要做的是捕获潜在的404并转发到错误处理程序，如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|636275|++++const+httpError+=+require('http-errors');

++++...

++++//+API+router
++++app.use('/api/',+routes);
++++
++++//+catch+404+and+forward+to+error+handler
++++app.use((req,+res,+next)+=>+{
++++++const+err+=+new+httpError(404)
++++++return+next(err);
++++});

++++module.exports+=+app;|code-block|syntax|javascript|636276|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

What I do after defining all routes is to catch potential 404 and forward to error handler, like this:
<pre><code> const httpError = require('http-errors');

 ...

 // API router
 app.use('/api/', routes);
 
 // catch 404 and forward to error handler
 app.use((req, res, next) =&gt; {
 const err = new httpError(404)
 return next(err);
 });

 module.exports = app;
</code></pre>

blocks|key|852709|text|在Express中，404响应不是错误的结果，因此错误处理中间件不会捕获它们。您需要做的就是在堆栈的最底层(在所有其他函数的下面)添加一个中间件函数来处理404响应：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852710|app.use(function+(req,+res,+next)+{
//+YOU+CAN+CREATE+A+CUSTOM+EJS+FILE+TO+SHOW+CUSTOM+ERROR+MESSAGE
++res.status(404).render("404.ejs")
})|code-block|syntax|javascript|852711|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

In Express, 404 responses are not the result of an error, so the error-handler middleware will not capture them. All you need to do is add a middleware function at the very bottom of the stack (below all other functions) to handle a 404 response:
<pre><code>app.use(function (req, res, next) {
// YOU CAN CREATE A CUSTOM EJS FILE TO SHOW CUSTOM ERROR MESSAGE
 res.status(404).render(&quot;404.ejs&quot;)
})
</code></pre>

blocks|key|852760|text|首先，创建一个route+js文件。接下来，创建一个error.ejs文件(如果您使用的是ejs)。最后，在路由文件中添加以下代码|type|unstyled|depth|inlineStyleRanges|entityRanges|data|852761|router.get('*',+function(req,+res){
++++res.render('error');
});|code-block|syntax|javascript|852762|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

First, create a route js file. Next, create a error.ejs file (if you are using ejs). Finally, add the following code in your route file
<pre><code>router.get('*', function(req, res){
 res.render('error');
});
</code></pre>

blocks|key|635814|text|app.get('*',function(req,res){
+res.redirect('/login');
});|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|635815|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>app.get('*',function(req,res){
 res.redirect('/login');
});
</code></pre>

I don't know a function for doing this, does anyone know of one?

How to redirect 404 errors to a page in ExpressJS?

我不知道做这件事的函数，有人知道吗？

问如何在ExpressJS中将404错误重定向到页面？
EN

回答 22

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