Portable web browser embedded in java app?_问答_开发者

Question: embed a portable web browser without cache into a java app? Using Java SE. Can this be done? Are there any JNI supports for e.g. Chrome or Firefox?

Maybe Qt? QtJambi w开发者_Go百科ould allow interfacing with the Webbrowser? From what I understand QtJambi is now maintained by the community and LPGL, is QtWebbrowser embeddable for this purpose in the same licence?

Examining the available documentation and over the past few days this is what has emerged:

The open source browsers are Webkit (which is used for e.g. Safari), and the Mozilla flavoured Firefox. There is also Chromium which is the open source version of the Google flavoured Chrome which uses a lesser javascript engine (squirrel as opposed to v8) and does not have the multi-separate-thread modularisation of Google Chrome.

Additional information on Firefox: Mozilla Firefox is based on an application called xulrunner which uses xml and javascript to provide the additional functionality of firefox (other than the 'not so basic' browser - such things as the html parser, css renderer and javascript parser). Xulrunner is the implementation of the browser.

Firefox implements its own private xulrunner, however additionally there is xulrunner as a standalone install.

Xulrunner can be used to create standalone applications, that are based on a web-browser, and has support for javascript. Xulrunner is also used to create the plugins for firefox providing additional functionality.

In order to connect the front end to something a bit more sustained and powerful than javascript (which has improved in leaps and bounds in recent years), but is still not the strongest sustained engine, there is a C-library called xpcom.

Xulrunner uses xpcom (written in C) to expose the javascript variables and parse the dom, and link javascript variables, and do other 'browsery' things like read headers etc. More on Xulrunner and xpcom in a moment.

If you want a browser that is recent and functional (html 4 or 5, good support for css2 at least, and some css3, and solid rendering of javascript), your best bet other than compiling and embedding one of these open source browsers is to use SWT.

SWT is a gui interface, similar to swing, except that it implements a webbrowser type interface, and can be used to implement a browser. SWT also has some developed interfaces to interact both with the dom and the like. SWT was developed by IBM and is actively maintained.

What SWT does is implement the OS system browser, and has support for every major os. On the upside, this means that there is no need to embed your own browser, on the downside you are stuck with whatever browser / parsers exist on the operating systems, at whichever version. The default behaviour on a windows os for SWT is to use Internet Explorer.

It is also possible to implement non-os linked browsers like firefox by installing xulrunner, but this is an additional 20mb (not extensive but something to note), as the more recent versions of firefox are not recognised.

It is a requirement to have javaxpcom support and xulrunner to implement a firefox style browser in SWT. The easiest way to go about getting the last version supported by Firefox (xulrunner 1.9.) for javaxpcom is to download an application called prism. Prism uses xulrunner as its base to create browsers that are standalone to specific urls. There is a known hacked xulrunner 1.9. which has some issues - see wikipedia for information on this, if you aim to download xulrunner 1.9.* compiled already from source.

Xulrunner is developed alongside each and every new edition of the Firefox browser. Until v 1.9.* (firefox 3.* if I am not mistaken), there was additional support for a function called javaxpcom which was an interface written to link the c library Xpcom's functions to java.

Firefox's initial announcement of how easy and simple it was to embed and style your own flavour of xulrunner, and that it was easy to port to many different languages (support for C, initially support for Java, Python amongst others), but obviously there is some overhead to accessing and adding libraries.

Xulrunner is being promoted as a potential software solution to compete in the same playing field as java, but suffers the same limitations of javascript / html applications. Within those parameters it functions.

Since version 2 of xulrunner, support for javaxpcom has withered, as there is no active maintainer of that code. It is open source solution so presumably interest from someone with requisite skills might pick that up. Xulrunner is now recently in version 6 at the time of writing this answer. Xpcom however is still going strong. Presumably there was insufficient interest / activity in the community, amongst other potential issues.

Since javaxpcom has been reported to have broken, and requires someone to maintain an interest in the code; that work would have to come from someone who has a vested understanding of Xulrunners xpcom, or at least a collaboration from someone who has an understanding of changes made in xpcom. Comments from what I have read suggest that documentation on xulrunner may not be a detailed as it could be, nor on javaxpcom, but I am not in a position to evaluate these comments.

I had hoped that the basic core functionality could simply have been maintained, keeping the hard work involved in recent browser improvements in functionality 'embeddable'. Firefox's amendments have resulted in extensions breaking in newer versions, a function of keeping up with the times.

A non-open source solution that embeds a web-browser and the like is called webrenderer.com. It is maintained, but there is a price tag attached, which is not insignificant.

Another possible route to implement a web-browser in a java application is to go the route of a cross platform development platform called Qt. QtJambi is a LPGL licensed (previously commercial) webbrowser that has extensive documentation and support for Java implementation. There is obviously learning curve attached to using any new platform. Reasons for the move from commercial to LPGL? Presumably viability and commercial demand for java supported browsers has .... waned? A function of the times we live in no doubt.

GWT is the java / webbrowser google solution. GWT works by allowing developers to write java solutions, and then ports and converts this solution into a stable javascript that can be obfuscated. However GWT is not suited to developing a desktop type application, in the sense that it requires a 'server' implementation for the backend. In this sense it is most suited or similar to a PHP or ASP style client / server solution.

Whilst it is not impossible to write GWT as a desktop application, presumably you would have to implement Apache Derby, or Jetty or similar as an in-house server to do all the to-ing and fro-ing. Its not neat, elegant or specifically designed for this, but madder solutions have been tried. There have been php style desktop applications.

For a number of political and financially motivated reasons it appears that support for porting / embedding java and open source browsers is not on the up and up, a trend which began with apple's lack of interest in supporting java applications. Mind you, the browsers are open source and presumably with enough time and energy, javaxpcom etc. could be sustained, but who is going to do this for free, I do not know.

Java promised a java browser implementation but this was not released with the Java 7, and requires like most other things, an amount of work. Perhaps in 8? It is unclear even there if it will be ready by then, I can't quite work out if its currently on the roadmap or not, and doesn't appear to be their highest priority include.

SWT requires some additional libraries and installation to work on various platforms.

Some other open source solutions which do at least in part appear to work, but the maintenance, support and current interest in appears mixed to none, include JRex, MozSwing. Rhino is a javascript engine, flying saucer an html4 renderer.

If you are talking about Java SE based application I would highly recommend swt 'Browser' component. I have used it myself within Eclipse RCP based app and it works like a charm (flash, javascript support)