**In html file add script tag**
<head>
<script type="text/javascript" src="https://raw.github.com/mozilla/pdf.js/gh-pages/build/pdf.js"></script>
</head>
<body>
<button id="prev" onclick="goPrevious()">Previous</button>
<button id="next" onclick="goNext()">Next</button>
<span>Page: <span id="page_num"></span>
<span id="page_count"></span></span>
</div>
<div>
<canvas id="the-canvas" width="700" style="border:1px solid black"></canvas>
</div>
</body>
and in client side (pdf.java) call a java script funcion using JSNI alse paste pdf.js file in public folder and call .gwt.xml like
**I am just follow this link http://jsbin.com/pdfjs-prevnext-v2/1/edit**
public void onModuleLoad() {
alert1();
}
private native void alert1 ()
/*-{
var url = 'http://cdn.mozilla.net/pdfjs/tracemonkey.pdf';
PDFJS.disableWorker = true;
var pdfDoc = null,
pageNum = 1,
scale = 0.8,
canvas = document.getElementById('the-canvas'),
ctx = canvas.getContext('2d');
function renderPage(num) {
// Using promise to fetch the page
pdfDoc.getPage(num).then(function(page) {
var viewport = page.getViewport(canvas.width / page.getViewport(1.0).width);
canvas.height = viewport.height;
// Render PDF page into canvas context
var renderContext = {
canvasContext: ctx,
viewport: viewport
};
page.render(renderContext);
});
document.getElementById('page_num').textContent = pageNum;
document.getElementById('page_count').textContent = pdfDoc.numPages;
}
function goPrevious() {
if (pageNum <= 1) return;
pageNum--;
renderPage(pageNum);
}
function goNext() {
if (pageNum >= pdfDoc.numPages) return;
pageNum++;
renderPage(pageNum);
}
PDFJS.getDocument(url).then(function getPdfHelloWorld(_pdfDoc) {
pdfDoc = _pdfDoc;
renderPage(pageNum);
});
}-*/;
11:27:17.679 [ERROR] [pdf] Unable to load module entry point class com.ruchi.client.Pdf (see associated exception for details) com.google.gwt.core.client.JavaScriptException: (ReferenceError): PDFJS is not defined at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:248) at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:136) at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561) at com.google.gwt.dev.shell.ModuleSpace.invokeNativeVoid(ModuleSpace.java:289) at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeVoid(JavaScriptHost.java:107) at com.ruchi.client.Pdf.alert1(Pdf.java) at com.ruchi.client.Pdf.onModuleLoad(Pdf.java:27) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at com.google.gwt.dev.shell.ModuleSpace.onLoad(ModuleSpace.java:396) at com.google.gwt.dev.shell.OophmSessionHandler.loadModule(OophmSessionHandler.java:200) at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:525) at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:363) at java.lang.Thread.run(Unknown Source)
plz suggest me what i do....
You are just blindly copy pasting javascript code into JSNI block.
Example if in your html js block you have
function test() {
alert('hello');
}
In your JSNI
private static native int test() /*-{
var v = $wnd.test();
return v;
}-*/;
Do you notice the use of $wnd
1) HTML should have
<span>Page: <span id="page_num"></span> of <span id="page_count"></span></span>
<div>
<canvas id="the-canvas" width="700" style="border: 1px solid black"></canvas>
</div>
2) Move pdf.js to local folder ( aovid script tag in html file requesting over internet )
3) Instead add <script src="PDF.js" /> in your module.gwt.xml file. Copy https://raw.github.com/mozilla/pdf.js/gh-pages/build/pdf.js into your GWT's public folder.
4) Modify your JSNI code
/*-{
var url = 'http://cdn.mozilla.net/pdfjs/tracemonkey.pdf';
$wnd.PDFJS.disableWorker = true;
var pdfDoc = null,
pageNum = 1,
scale = 0.8,
canvas = $wnd.document.getElementById('the-canvas'),
ctx = canvas.getContext('2d');
function renderPage(num) {
// Using promise to fetch the page
pdfDoc.getPage(num).then(function(page) {
var viewport = page.getViewport(canvas.width / page.getViewport(1.0).width);
canvas.height = viewport.height;
// Render PDF page into canvas context
var renderContext = {
canvasContext: ctx,
viewport: viewport
};
page.render(renderContext);
});
$wnd.document.getElementById('page_num').textContent = pageNum;
$wnd.document.getElementById('page_count').textContent = pdfDoc.numPages;
}
function goPrevious() {
if (pageNum <= 1) return;
pageNum--;
renderPage(pageNum);
}
function goNext() {
if (pageNum >= pdfDoc.numPages) return;
pageNum++;
renderPage(pageNum);
}
$wnd.PDFJS.getDocument(url).then(function getPdfHelloWorld(_pdfDoc) {
pdfDoc = _pdfDoc;
renderPage(pageNum);
});
}-*/;
5) You should be able to solve Next/Prev similarly. Avoid raising one more question to solve that. You should try doing some "HOMEWork"
JSNI 101: you have to use $wnd.PDFJS instead of PDFJS.
来源：https://stackoverflow.com/questions/14152131/using-pdf-js-exception-occur-javascriptexception-referenceerror-pdfjs-is-not