对于初学者,可以将本文视为在IDEA中重构Java文件的快速gif 。
小心,有很多沉重的GIF。
“任何傻瓜都可以编写计算机可以理解的代码。优秀的程序员可以编写人类可以理解的代码。” -M. Fowler(1999)
内容
- Find and Replace Code Duplicate
- Use Interface Where Possible
- Replace Inheritance with Delegation
- Replace Constructor with Factory Method
- Replace Constructor with Builder
, , IDEA, , . , , Refator:
, , idea
, . , , Refactoring: Improving the Design of Existing Code (Martin Fowler). gif-, . Windows/LInux .
«Refator»
.
«Refactor This» (Ctrl+Alt+Shift+T)
. , , . , .
«Rename» (Shift+F6)
, . , , . ( 2 - “Rename Field” “Rename Variable”)
public class Main {
public static void main(String[] args) {
System.out.print("Hello");
invo<caret/>ke(", World");
}
private static void invoke(String text) {
//text
System.out.println(text);
}
}
public class Main {
public static void main(String[] args) {
System.out.print("Hello");
newFunctionName(", World");
}
private static void newFunctionName(String text) {
//text
System.out.println(text);
}
}
public class Main {
public static void main(String[] args) {
System.out.print("Hello");
invoke(", World");
}
private static void invoke(String te<caret>xt) {
//text
System.out.println(text);
}
}
public class Main {
public static void main(String[] args) {
System.out.print("Hello");
invoke(", World");
}
private static void invoke(String newText) {
//newText
System.out.println(newText);
}
}
public class Main {
public static void main(String[] args) {
System.out.print("Hello");
invoke(", World");
}
private static void invoke(String text) {
//text
System.out.println(text);
throw new MyExc<caret>eption();
}
public static class MyException extends RuntimeException {
}
}
public class Main {
public static void main(String[] args) {
System.out.print("Hello");
invoke(", World");
}
private static void invoke(String text) {
//text
System.out.println(text);
throw new NewMyException ();
}
public static class NewMyException extends RuntimeException {
}
}
public class Main {
public static void main(String[] args) {
MyS<caret>ervice service = new MyService();
service.service();
}
}
public class Main {
public static void main(String[] args) {
NewMyService myService = new NewMyService ();
myService.service();
}
}
package gen<caret>eral;
public class Main {
public static void main(String[] args) {
NewMyService service = new NewMyService();
service.service();
}
}
package org.test.java.src;
public class Main {
public static void main(String[] args) {
NewMyService service = new NewMyService();
service.service();
}
}
«Rename File»
. Shift+F6 . (Scope),
public class Main {
public static void main(String[] args) throws IOException {
Path path = Paths.get("src/general/TestFile.txt");
String read = Files.readAllLines(path).get(0);
System.out.println(read);
}
}
public class Main {
public static void main(String[] args) throws IOException {
Path path = Paths.get("src/general/TestFile2.txt");
String read = Files.readAllLines(path).get(0);
System.out.println(read);
}
}
«Change Signature» (Ctrl+F6)
“Change Function Declaration”. IDEA «Change Signature» . :
- - ,
- .
( )
. "R" "Update usages to reflect signature change", .
public class ChangeSignature {
public static void main(String[] args) {
invokeMethod("Hello");
invokeMethod("World");
}
private static void invokeMethod(String text) {
System.out.println(text);
}
}
public class ChangeSignature {
public static void main(String[] args) {
invokeMethod("Hello", null);
invokeMethod("World", null);
}
private static void invokeMethod(String text, String newType) {
System.out.println(text);
}
}
( )
, exception, .
public class ChangeSignature {
public static void main(String[] args) {
invokeMethod("Hello");
invokeMethod("World");
}
private static void invokeMethod(String<caret> text) {
System.out.println(text);
}
}
public class ChangeSignature {
public static void main(String[] args) {
invokeMethod("Hello");
invokeMethod("World");
}
private static void invokeMethod(String text) {
invokeMethod(text, null);
}
private static void invokeMethod(String text, String newName) {
System.out.println(text);
}
}
«Edit Property Value» (Alt + F6)
(Idea 2020.2) . property.value.inplace.editing=true .
«Type Migration» (Ctrl + Shift + F6)
, , .
public class ChangeSignature {
public static void main(String[] args) {
Inte<caret>ger hello = 1;
print(hello);
}
private static void print(Integer text) {
System.out.println(text);
}
}
public class ChangeSignature {
public static void main(String[] args) {
Number hello = 1;
print(hello);
}
private static void print(Number text) {
System.out.println(text);
}
}
«Make Static» (Ctrl + Shift + F6)
. ( Convert To Instance Method)
public class MakeStatic {
public static void main(String[] args) {
MakeStatic makeStatic = new MakeStatic();
makeStatic.sayHello();
}
public void say<caret>Hello() {
System.out.println("Hello, World");
}
}
public class MakeStatic {
public static void main(String[] args) {
MakeStatic makeStatic = new MakeStatic();
MakeStatic.sayHello();
}
public static void sayHello() {
System.out.println("Hello, World");
}
}
«Convert To Instance Method»
( ”Make Static”). .
public class MakeStatic {
public static void main(String[] args) {
sayHello();
}
public static void sa<caret>yHello() {
System.out.println("Hello, World");
}
}
public class MakeStatic {
public static void main(String[] args) {
new MakeStatic().sayHello();
}
public void sayHello() {
System.out.println("Hello, World");
}
}
«Move Classes» (F6)
, , .
package org.example.test.service;
public class TestService {
<caret>
}
package org.example.test;
public class TestService {
}
«Copy Classes» (F5)
, . F5. e, .
«Safe Delete» (Alt+Delete)
, (Alt + Enter), . , , - F2( ) Alt + Enter Alt + Delete. , , . IDEA , IDEA , - Usages Detected. - “Remove Dead Code”
package org.example.test;
public class MainClass {
public static void main(String[] args) {
start();
}
private static void start() {
String unUsedVariable;
System.out.println("Hello, World!");
}
private static void unUsedMethod() {
}
}
<empty>
«Extract/Introduce»
- Extract/Introduce. , . .
«Variable» (Ctrl+Alt+V)
. ( “Extract Variable”).
public class ExtractVariable {
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
System.out.println("He<caret>llo, World!");
}
}
public class ExtractVariable {
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
String text = "Hello, World!";
System.out.println(text);
}
}
«Constant» (Ctrl+Alt+C)
.
public class ExtractVariable {
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
System.out.println("He<caret>llo, World!");
}
}
public class ExtractVariable {
public static final String HELLO_WORLD = "Hello, World!";
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
System.out.println(HELLO_WORLD);
}
}
«Field» (Ctrl+Alt+F)
.
public class ExtractVariable {
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
System.out.println("He<caret>llo, World!");
}
}
public class ExtractVariable {
private static String x;
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
x = "Hello, World!";
System.out.println(x);
}
}
«Parameter» (Ctrl+Alt+P)
() .
public class ExtractVariable {
public static void main(String[] args) {
sayHello();
}
private static void sayHello() {
System.out.println("He<caret>llo, World!");
}
}
public class ExtractVariable {
public static void main(String[] args) {
sayHello("Hello, World!");
}
private static void sayHello(String x) {
System.out.println(x);
}
}
«Functional Parameter»
«Parameter», java.util.function.Supplier, javafx.util.Builder. , .
public class ExtractParameter {
public static void main(String[] args) {
System.out.println(generateText());
}
private static String generateText() {
return "Hello, Wor<caret>ld!".toUpperCase();
}
}
public class ExtractParameter {
public static void main(String[] args) {
System.out.println(generateText(() -> "Hello, World!"));
}
private static String generateText(final Supplier<string> getText) {
return getText.get().toUpperCase();
}
}
«Functional Variable»
«Variable», java.util.function.Supplier javafx.util.Builder.
public class ExtractParameter {
public static void main(String[] args) {
System.out.println(generateText());
}
private static String generateText() {
return "Hello, W<caret>orld!".toUpperCase();
}
}
public class ExtractParameter {
public static void main(String[] args) {
System.out.println(generateText());
}
private static String generateText() {
Supplier<string> getText = () -> "Hello, World!";
return getText.get().toUpperCase();
}
}
«Parameter Object»
, . ( “Introduce Parameter Object”).
public class ExtractParameter {
public static void main(String[] args) {
System.out.println(generateText("Hello", "World!"));
}
private static String generateText(Str<caret>ing hello, String world) {
return hello.toUpperCase() + world.toUpperCase();
}
}
public class ExtractParameter {
public static void main(String[] args) {
System.out.println(generateText(new HelloWorld("Hello", "World!")));
}
private static String generateText(HelloWorld helloWorld) {
return helloWorld.getHello().toUpperCase() + helloWorld.getWorld().toUpperCase();
}
private static class HelloWorld {
private final String hello;
private final String world;
private HelloWorld(String hello, String world) {
this.hello = hello;
this.world = world;
}
public String getHello() {
return hello;
}
public String getWorld() {
return world;
}
}
}
«Method» (Ctrl+Alt+M)
. ( - “Extract Function”).
public class ExtractMethod {
public static void main(String[] args) {
String text = "Hello, World!";
System.out.prin<caret>tln(text);
}
}
public class ExtractMethod {
public static void main(String[] args) {
String text = "Hello, World!";
print(text);
}
private static void print(String text) {
System.out.println(text);
}
}
«Type Parameter»
Kotlin, Java ( , - ).
«Replace Method With Method Object»
. , ( -).
public class ExtractMethod {
public static void main(String[] args) {
String text = "Hello, World!";
print(text);
}
private static void print(String text) {
System.out.p<caret>rintln(text);
}
}
public class ExtractMethod {
public static void main(String[] args) {
String text = "Hello, World!";
print(text);
}
private static void print(String text) {
new Printer(text).invoke();
}
private static class Printer {
private String text;
public Printer(String text) {
this.text = text;
}
public void invoke() {
System.out.println(text);
}
}
}
«Delegate»
.
public class Delegate {
public static void main(String[] args) {
new Delegate().print();
}
private void print() {
System.ou<caret>t.println("Hello, World!");
}
}
public class Delegate {
private final Printer printer = new Printer();
public static void main(String[] args) {
new Delegate().print();
}
private void print() {
printer.print();
}
public static class Printer {
public Printer() {
}
private void print() {
System.out.println("Hello, World!");
}
}
}
«Interface»
. ( , Spring, - )
public class ExtractImpl {
public static void main(String[] args) {
new ExtractImpl().print();
}
public void print() {
System.out.println("Hello, World!");
}
}
public class ExtractImpl implements ExtractInterface {
public static void main(String[] args) {
new ExtractImpl().print();
}
@Override
public void print() {
System.out.println("Hello, World!");
}
}
public interface ExtractInterface {
void print();
}
«Superclass»
«Interface», - (Superclass). “Extract Superclass”.
public class ExtractImpl {
public static void main(String[] args) {
new ExtractImpl().print();
}
public void print() {
System.out.println("Hello, World!");
}
}
public class ExtractImpl extends ExtractAbstr {
public static void main(String[] args) {
new ExtractImpl().print();
}
}
public class ExtractAbstr {
public void print() {
System.out.println("Hello, World!");
}
}
«Subquery as CTE»
Sql, . - , - .
«RSpec 'let'»
Ruby, - , - .
«Inline»
, . “Inline Class”, “Inline Function”, “Inline Variable”.
public class Inline {
public static void main(String[] args) {
print();
}
private static void print() {
new Printer().print();
}
private static class Printer {
public void print() {
String text = "Hello, World!";
System.out.println(t<caret>ext);
}
}
}
public class Inline {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
«Find and Replace code duplicate»
, , .
public class Replace {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
public void print() {
System.out.println("Hello, World!");
}
public void print2() {
System.out.prin<caret>tln("Hello, World!");
}
}
public class Replace {
public static void main(String[] args) {
print2();
}
public void print() {
print2();
}
public static void print2() {
System.out.println("Hello, World!");
}
}
«Invert Boolean»
.
public class Invert {
public static void main(String[] args) {
boolean co<caret>ndition = true;
if (condition) {
System.out.println("Hello, World!");
}
}
}
public class Invert {
public static void main(String[] args) {
boolean condition = false;
if (!condition) {
System.out.println("Hello, World!");
}
}
}
«Pull Member Up»
. “Pull Up Field” “Pull Up Method”. «Pull Member Down».
public class PullMethod {
public static void main(String[] args) {
new InnerClass().print();
}
private static class InnerClass extends AbstClass {
public void print() {
System.out.pri<caret>ntln("Hello, World");
}
}
private static abstract class AbstClass {
}
}
public class PullMethod {
public static void main(String[] args) {
new InnerClass().print();
}
private static class InnerClass extends AbstClass {
}
private static abstract class AbstClass {
public void print() {
System.out.println("Hello, World");
}
}
}
«Pull Member Down»
«Pull Member Up». . ( - “Push Down Method”)
public class PullMethod {
public static void main(String[] args) {
new InnerClass().print();
}
private static class InnerClass extends AbstClass {
}
private static abstract class AbstClass {
public void print() {
System.out.prin<caret>tln("Hello, World");
}
}
}
public class PullMethod {
public static void main(String[] args) {
new InnerClass().print();
}
private static class InnerClass extends AbstClass {
@Override
public void print() {
System.out.println("Hello, World");
}
}
private static abstract class AbstClass {
public abstract void print();
}
}
«Push ITds In»
AsperctJ.
aspect myAspect {
boolean Account.closed = <caret>false;
void Account.close() {
closed = true;
}
}
class Account {
}
aspect myAspect {
boolean Account.closed = false;
}
class Account {
void close() {
closed = true;
}
}
«Use Interface Where Possible»
IDEA , , .
public class ExtractInterface {
public static void main(String[] args) {
InnerClass innerClass = new InnerClass();
print(innerClass);
}
private static void print(InnerClass innerClass) {
innerClass.print();
}
private static class InnerClass implements InnerInterface{
@Override
public void print() {
System.out.println("Hello, World!");
}
}
private static interface InnerInterface{
void print();
}
}
public class ExtractInterface {
public static void main(String[] args) {
InnerInterface innerClass = new InnerClass();
print(innerClass);
}
private static void print(InnerInterface innerClass) {
innerClass.print();
}
private static class InnerClass implements InnerInterface{
@Override
public void print() {
System.out.println("Hello, World!");
}
}
private static interface InnerInterface{
void print();
}
}
«Replace Inheritance with Delegation»
. “Replace Subclass with Delegate” “Replace Superclass with Delegate”.
public class InheritanceDelegation {
public static void main(String[] args) {
InnerClass innerClass = new InnerClass();
print(innerClass);
}
private static void print(InnerClass innerClass) {
innerClass.print();
}
private static class In<caret>nerClass extends AbstractClass {
}
private static class AbstractClass {
public void print() {
System.out.println("Hello, World!");
}
}
}
public class InheritanceDelegation {
public static void main(String[] args) {
InnerClass innerClass = new InnerClass();
print(innerClass);
}
private static void print(InnerClass innerClass) {
innerClass.print();
}
private static class InnerClass {
private final AbstractClass abstractClass = new AbstractClass();
public void print() {
abstractClass.print();
}
}
private static class AbstractClass {
public void print() {
System.out.println("Hello, World!");
}
}
}
«Remove Middleman»
. ( - “Remove Middle Man”).
public class Middleman {
public static void main(String[] args) {
InnerClass innerClass = new InnerClass();
innerClass.print();
}
private static class InnerClass {
private final NextClass next<caret>Class = new NextClass();
public void print() {
nextClass.print();
}
}
private static class NextClass {
public void print() {
System.out.println("Hello, World!");
}
}
}
public class Middleman {
public static void main(String[] args) {
InnerClass innerClass = new InnerClass();
innerClass.getNextClass().print();
}
private static class InnerClass {
private final NextClass nextClass = new NextClass();
public NextClass getNextClass() {
return nextClass;
}
}
private static class NextClass {
public void print() {
System.out.println("Hello, World!");
}
}
}
«Wrap Method Return Value»
-. , .
public class WrapMethodReturnValue {
public static void main(String[] args) {
System.out.println(new MessageFolder().get());
}
private static class MessageFolder {
public String get() {
ret<caret>urn "Hello, World!";
}
}
}
public class WrapMethodReturnValue {
public static void main(String[] args) {
System.out.println(new MessageFolder().get().getValue());
}
private static class MessageFolder {
public Message get() {
return new Message("Hello, World!");
}
public class Message {
private final String value;
public Message(String value) {
this.value = value;
}
public String getValue() {
return value;
}
}
}
}
«Encapsulate Field»
getter, setter.
public class EncapsulateField {
public static void main(String[] args) {
System.out.println(new InnerClass().message);
}
private static class InnerClass {
public String m<caret>essage = "Hello, World!";
}
}
public class EncapsulateField {
public static void main(String[] args) {
System.out.println(new InnerClass().getMessage());
}
private static class InnerClass {
private String message = "Hello, World!";
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
}
}
«Replace Temp with Query»
int size = getActualSize()
size getActualSize(). , . .
public class ReplaceTemp {
public static void main(String[] args) {
String hello = "Hello";
String mes<caret>sage = hello + ", World!";
System.out.println(message);
}
}
public class ReplaceTemp {
public static void main(String[] args) {
String hello = "Hello";
System.out.println(message(hello));
}
private static String message(String hello) {
return hello + ", World!";
}
}
«Replace Constructor with Factory Method»
. , Lombok. ( “Replace Constructor with Factory Function”).
public class ReplaceConstructor {
public static void main(String[] args) {
new InnerClass("Hello", "World").print();
}
private static class InnerClass {
private String message;
public Inner<caret>Class(String hello, String world) {
message = hello + ", " + world;
}
public void print() {
System.out.println(message);
}
}
}
public class ReplaceConstructor {
public static void main(String[] args) {
InnerClass.createInnerClass("Hello", "World").print();
}
private static class InnerClass {
private String message;
private InnerClass(String hello, String world) {
message = hello + ", " + world;
}
public static InnerClass createInnerClass(String hello, String world) {
return new InnerClass(hello, world);
}
public void print() {
System.out.println(message);
}
}
}
«Replace Constructor with Builder»
builder . , Lombok.
public class ReplaceConstructor {
public static void main(String[] args) {
new InnerClass("Hello", "World").print();
}
private static class InnerClass {
private String message;
public InnerC<caret>lass(String hello, String world) {
message = hello + ", " + world;
}
public void print() {
System.out.println(message);
}
}
}
public class ReplaceConstructor {
public static void main(String[] args) {
new InnerClassBuilder().setHello("Hello").setWorld("World").createInnerClass().print();
}
static class InnerClass {
private String message;
public InnerClass(String hello, String world) {
message = hello + ", " + world;
}
public void print() {
System.out.println(message);
}
}
}
public class InnerClassBuilder {
private String hello;
private String world;
public InnerClassBuilder setHello(String hello) {
this.hello = hello;
return this;
}
public InnerClassBuilder setWorld(String world) {
this.world = world;
return this;
}
public ReplaceConstructor.InnerClass createInnerClass() {
return new ReplaceConstructor.InnerClass(hello, world);
}
}
«Generify»
raw- Generic-. java 1.5 .
public class Generify {
public static void main(String[] args) {
List list = getList();
Object message = list.get(0);
System.out.println(message);
}
private static List getList() {
ArrayList arrayList = new ArrayList();
arrayList.add("Hello, World!");
return arrayList;
}
}
public class Generify {
public static void main(String[] args) {
List<string> list = getList();
String message = list.get(0);
System.out.println(message);
}
private static List<string> getList() {
ArrayList<string> arrayList = new ArrayList<>();
arrayList.add("Hello, World!");
return arrayList;
}
}
«Migrate»
:
. , , JUnit(4.x -> 5.0):
«Lombok» «Delombok»
由插件“ Lombok”提供。最近宣布,它将现在包含在标准IDEA软件包中。在使用“ Lombok”代码生成库时使用。
项目“国际化”
用于国际化。不幸的是,我目前没有在帮助中找到任何信息。IDEA现在正在积极地本地化为其他语言,很可能是为此开发了这种方法。
来源清单
优秀的谈话大约从Tagir Valeev原子重构