Hidden features of Eclipse [closed]

问题:

Alright it can be a lame question, but everybody uses these things differently. What\'s some of the best time savers out there for this IDE.

Tom

回答1:

Don\'t forget Ctrl+Shift+L, which displays a list of all the keyboard shortcut combinations (just in case you forget any of those listed here).

回答2:

Ctrl-2 something

Seems that nobody mentioned Ctrl-2 L (assign to new local variable) and Ctrl-2 F (assign to a new field), these ones have changed how I write code.

Previously, I was typing, say (| is cursor location):

Display display = new |

and then I pushed Ctrl-Space to complete the constructor call. Now I type:

new Display()|

and press Ctrl-2 L, which results in:

Display display = new Display()|

This really speeds things up. (Ctrl-2 F does the same, but assigns to a new field rather than a new variable.)

Another good shortcut is Ctrl-2 R: rename in file. It is much faster than rename refactoring (Alt-Shift-R) when renaming things like local variables.

Actually I went to Keys customization preference page and assigned all sorts of additional quick fixes to Ctrl-2-something. For example I now press Ctrl-2 J to split/join variable declaration, Ctrl-2 C to extract an inner class into top-level, Ctrl-2 T to add throws declaration to the function, etc. There are tons of assignable quick fixes, go pick your favourite ones and assign them to Ctrl-2 shortcuts.

Templates

Another favourite of mine in my “npe” template, defined as:

if (${arg:localVar} == null)
    throw new ${exception:link(NullPointerException,IllegalArgumentException)}(\"${arg:localVar} is null\");

This allows me to quickly add null argument checks at the start of every function (especially ones that merely save the argument into a field or add it into a collection, especially constructors), which is great for detecting bugs early.

See more useful templates at www.tarantsov.com/eclipse/templates/. I won\'t list them all here because there are many, and because I often add new ones.

Completion

A few code completion tricks:

• camel case support mentioned in another answer: type cTM, get currentTimeMillis
• default constructor: in the class declaration with no default constructor push Ctrl-Space, the first choice will be to create one
• overloading: in the class declaration start typing name of a method you can overload, Ctrl-Space, pick one
• getter/setter creation: type “get”, Ctrl-Space, choose a getter to create; same with “is” and “set”

Assign To A New Field

This is how I add fields.

1. If you have no constructors yet, add one. (Ctrl-Space anywhere in a class declaration, pick the first proposal.)

2. Add an argument (| is cursor position):

   public class MyClass {
       public MyClass(int something|) {
       }
   }
   

3. Press Ctrl-1, choose “assign to a new field”. You get:

   public class MyClass {
       private final Object something;
       public MyClass(Object something) {
           this.something = something;
       }
   }
   

4. Add a null-pointer check if appropriate (see “npe” template above):

   public class MyClass {
       private final Object something;
       public MyClass(Object something) {
           npe|
           this.something = something;
       }
   }
   

   Hit Ctrl-Space, get:

   public class MyClass {
       private final Object something;
       public MyClass(Object something) {
           if (something == null)
               throw new NullPointerException(\"something is null\");
           this.something = something;
       }
   }
   

A great time saver!

回答3:

ctrl-shift-r and its buddy, ctrl-shift-t, to open a resource or type, respectively. Resources includes all files in your open projects (including non-java files), and types includes java types either in your projects, or in a library included in the projects.

回答4:

Crtl+1 is my favorite. The quick fixes for the red-squiggles.

It is also located in the Edit Menu -> Quick Fix.

回答5:

Ctrl+Shift+O to organize imports, which will format them nicely, remove unneeded imports, and add missing imports.

回答6:

Ctrl-J starts an incremental find.

Hit Ctrl-J, then start typing. Use up/down to find previous/next instances of what you typed.

Ctrl-Shift-J searches backwards.

回答7:

Type \'syso\' then press Ctrl+Space to expand it to System.out.println().

Tres handy.

回答8:

CTRL+3 brings up a type-ahead list of any menu command.

回答9:

• CTRL-SHIFT-g : finds usages of the method or field under the cursor, absolutely necessary for understanding code
• CTRL-F6 : navigate between the list of open editor windows, if you just type it once and let go you toggle back to the previous editor window, doing this successively is a nice way to jump back and forth
• CTRL-t : on a class or method will show you the type hierarchy, very useful for finding implementations of an interface method for example

回答10:

Clicking on the return type in a method\'s declaration highlights all exit points of the method.

for instance:

1: public void foo()
2: {
3:   somecode();
4:    if ( blah ) return;
5:
6:    bar();
7: }

clicking on void will highlight the return on line 4 and the close } on line 7.

Update: It even works for try{} catch blocks. If you put cursor on exception in the catch block and eclipse will highlight the probable methods which may throw that exception.

回答11:

Code completion supports CamelCase, e.g., typing CWAR will show a result for ClassWithAReallyLongName. Start using this feature and you\'ll never type another long classname again.

(parts copied from another answer because i think answers w/ just one hint/tip are best for polling)

回答12:

Alt-Up Arrow moves the current selection up a line, Alt-Down Arrow moves it down. I also use Alt-Shift-Up/Down Arrow all the time. Ctrl-K and Ctrl-Shift-K is quite handy, finding next/previous occurrence of the current selection (or the last Find, if nothing is selected).

回答13:

There\'s an option to place the opening curly brace and a semicolon automagically in the \"correct\" position. You\'ll have to enable this - Choose Window/Preferences and type \"brace\" in the searchbox - should be easily findable (no eclipse on this computer). The effect:

• Typing a semicolon anywhere on the line will place it at this lines end (as in word/openoffice: Backspace if you\'d like to have it in the original place)
• Typing an opening curly brace when you\'re just inside another pair of braces will place it at the end of this line - as in this example

(\"|\" is the cursor):

if(i==0|)

typing \"{\" now will result in

if(i==0) {|

回答14:

Hippie expand/Word Complete, afaik inspired by Emacs: will autocomplete any word in any editor based on other words in that file. Autocomplete inside String literals in Java code, in xml files, everywhere.

Alt + /

回答15:

Alt-Shift-R stands for rename, not refactor. Refactoring is a more general term (as defined by the book).

Nevertheless, it is one of my favorite refactorings. Others include:

• Alt-Shift-M: Extract Method (when a code block or an expression is selected)

• Alt-Shift-L: Extract Local Variable (when an expression is selected)

Extract Local Variable is especially useful when I don\'t remember (or bother to type) the result type of a method. Assuming you have a method JdbcTemplate createJdbcTemplate() in your class, write some code such as this:

void someQuery() {
    createJdbcTemplate()
}

Select the expression createJdbcTemplate(), click Alt-Shift-L, type the name of variable and press enter.

void someQuery() {
    JdbcTemplate myTemplate = createJdbcTemplate();
}

回答16:

CTRL + D - to delete current line

回答17:

Absolutely, Ctrl+Q to go to last edit location. It is very useful just after being interrupted by phone, boss or others.

回答18:

Ctrl + Shift + M: changes a static method or static attribute reference of a class to a static import.

Before

import X;

...
X.callSomething();

After

import static X.callSomething;

...
callSomething();

回答19:

Alt+Shift+Up Arrow does escalating selection. Alt+Shift+Down does the opposite.

回答20:

Alt+Up or Alt+Down to move lines

回答21:

Nobody\'s mentioned the best one yet. Click on a class or method name and press Ctrl+T.

You get a quick type hierarchy. For a class name you see the entire class hierarchy. For a method name you get the hierarchy showing superclasses and subclasses, with implementations of that method distinguished from abstract mentions, or classes that don\'t mention the method.

This is huge when you are at an abstract method declaration and quickly want to see where it is implemented.

回答22:

F3 has been my favorite, opens the definition for the selected item.

Ctrl+Shift+R has an interesting feature, you can use just the uppercase camel letters from a class when searching (such as typing CWAR will show a result for ClassWithAReallyLongName).

Alt+Shift+W > Package Explorer makes life easier when browsing large projects.

回答23:

A non-keyboard shortcut trick is to use commit sets in your Team->Synchronise view to organise your changes before committing.

Set a change set to be the default, and all changes you make on files will be put in that set, making it easy to see what you have changed while working on a specific defect/feature, and other changes you had while testing etc.

回答24:

CTRL+SPACE, for anything, anywhere.

Generate getters and setters.

Create Constructors using Fields

Extract Method...

Refactor->Rename

CTRL+O for the quick outline. CTRL+O+CTRL+O for the inherited outline.

F4 to display a type hierarchy

Open Call Hierarchy to display where a method is called from.

CTRL+SHIFT+T to open a Java Type

CTRL+SHIFT+R to open any resource.

ALT + left or right to go forward or backwards through edit places in your documents (easy navigation)

Override/Implement methods if you know you\'re going to do a lot of methods (otherwise, CTRL+SPACE is better for one at a time selection.

Refactor->Extract Interface

Refactor->Pull up

Refactor->Push down

CTRL+SHIFT+O for organize imports (when typing the general class name such as Map, pressing CTRL+SPACE and then selecting the appropriate class will import it directly for you).

CTRL+SHIFT+F for formatting (although Eclipse\'s built in formatter can be a little braindead for long lines of code)

EDIT: Oh yeah, some debugging:

F5: Step into (show me the details!)

F6: Step over (I believe you, on to the next part...)

F7: Step out (I thought I cared about this method, but it turns out I don\'t, get me out of here!)

F8: Resume (go until the next breakpoint is reached)

CTRL+SHIFT+I: inspect an expression. CTRL+SHIFT+I+CTRL+SHIFT+I: create a watch expression on the inspected expression.

Conditional breakpoints: Right click a breakpoint and you may set a condition that occurs which triggers its breaking the execution of the program (context assist, with Ctrl+Space, is available here!)

F11 - Debug last launched (application)

CTRL+F11 - Run last launched (application)

回答25:

Breakpoint on Exception

Eclipse let you set breakpoints based on where an Exception occurs.
You access the option via the \"j!\" alt text http://help.eclipse.org/stable/topic/org.eclipse.jdt.doc.user/images/org.eclipse.jdt.debug.ui/elcl16/exc_catch.png icon in the debugging window.

alt text http://blogs.bytecode.com.au/glen/2007/04/06/images/2007/AddExceptionWindow.png

The official help topic \"Add Java Exception Breakpoint \" has more on this.

• The Uncaught Exception option is to suspend execution when an exception of the same type as the breakpoint is thrown in an uncaught location.
• The Caught Exception option is to suspend execution when an exception of the same type as the breakpoint is thrown in a caught location.
• do not forget the Exception Breakpoint Suspend on Subclass of this Exception:
  to suspend execution when subclasses of the exception type are encountered.
  For example, if an exception breakpoint for RuntimeException is configured to suspend on subclasses, it will also be triggered by a NullPointerException.

alt text http://help.eclipse.org/stable/topic/org.eclipse.jdt.doc.user/reference/breakpoints/images/ref-breakpoint_suspendsubclass.PNG

回答26:

Ctrl+Alt+H on a method to get the call hierarchy for it. Fast way to see where it is called from.

回答27:

Ctrl+Alt+UP or Ctrl+Alt+DOWN to copy lines

回答28:

Alt + Shift + R to refactor and rename.

回答29:

Here is my collection of the most useful keyboard shortcuts for Eclipse 3:

Eclipse 3 Favorite Keyboard Shortcuts. 
by -=MaGGuS=-

Navigate:

•   Ctrl + Shift + L – Shows useful keyboard shortcuts in popup window 
•   Ctrl + H – Search.
•   Ctrl + K – Goes to next search match in a single file. Shift + Ctrl + K – goes to previous match.
•   F3 - Goes to ‘declaration’ of something. Same as Ctrl + Click.
•   Ctrl + Shift + G - Use this on a method name or variable. It will search for references in the code (all the code) to that item.
•   Ctrl + O – Shows outline view of the current class or interface.
•   Ctrl + T – Shows class hierarchy of the current class or interface. F4 – shows the same in separate tab.
•   Ctrl + Shift + T - Open Type. Search for any type globally in the workspace.
•   Ctrl + Shift + R – Open Resource. Search for any file inside workspace.
•   Ctrl + J – Incremental search. Similar to the search in firefox. It shows you results as you type. Shift + Ctrl +J - Reverse incremental search.
•   Ctrl + Q – Goes to the last edit location.
•   Ctrl + Left|Right – Go Back/Forward in history.
•   Ctrl + L – Go to line number.
•   Ctrl + E – This will give you a list of all the source code windows that are currently open. You can arrow up or down on the items to go to a tab.
•   Ctrl +PgUp|PgDown – Cycles through editor tabs.
•   Ctrl + Shift + Up|Down - Bounces you up and down through the methods in the source code.
•   Ctrl + F7 – Switches between panes (views).
•   Ctrl + ,|. – Go to the previous/next error. Great in combination with Ctrl + 1.
•   Ctrl + 1 on an error – Brings up suggestions for fixing the error. The suggestions can be clicked.
•   Ctrl + F4 – Close one source window.

Edit:

•   Ctrl + Space – Auto-completion.
•   Ctrl + / – Toggle comment selected lines.
•   Ctrl + Shift + /|\\ – Block comment/uncomment selected lines.
•   Ctrl + Shift + F – Quickly ‘formats’ your java code based on your preferences set up under Window –> Preferences.
•   Ctrl + I – Correct indentations.
•   Alt + Up|Down – move the highlighted code up/down one line. If nothing is selected, selects the current line.
•   Ctrl + D – Delete row.
•   Alt + Shift + Up|Down|Left|Right – select increasing semantic units.
•   Ctrl + Shift + O – Organize Imports.
•   Alt + Shift + S – Brings up “Source” menu.
o   Shift + Alt + S, R – Generate getter/setter.
o   Shift + Alt + S, O – Generate constructor using fields.
o   Shift + Alt + S, C – Generate constructor from superclass.
•   Alt + Shift + T – Brings up “Refactor” menu.
•   Alt + Shift + J – Insert javadoc comment.
•   F2 – Display javadoc popup for current item. Shift + F2 – Display javadoc in external browser.

Run/Debug:

•   F11 / Ctrl + F11 – Execute/debug.
•   Ctrl + Shift +B – Toggle breakpoint.
•   When paused: F5 – Step into, F6 – Step over, F7 – Step out, F8 – Resume.
•   Ctrl + F2 – Terminate.

EOF

回答30:

Not so Hidden but IMO the best Trick.

Assuming Default Settings (and you have\'nt added new snippets)

Highlight (or select) a Text (String or Variable)...Press Ctrl+Space. Hit End+Enter. the \"sysout\" snippet is triggered which wraps the selection around as its parameter.

eg.

 \"hello world!\"

becomes
System.out.println(\"hello world!\");

I love it so much that i\'ve implemented a similar snippet for Android\'s Toast and Log.i() HUGE Time saver during Manual Debugging....