Spring assembly Bean (explicitly configured in Java)

1. Brief Introduction

Spring provides three kinds of assembly mechanisms:

1. Explicit configuration in xml;

2. Explicit configuration in java;

3. Implicit bean discovery Mechanism and auto-assembly.

of these, 1 and 3 items are used frequently in projects, and display configuration in Java is rarely used. This article focuses on the 2nd Approach.

If in the project we need to assemble a third-party library into spring, We cannot use implicit assembly (annotations that cannot be added to the Third-party library @component, etc.),

You need to select the method configuration in both explicit configurations.

The way in which it is explicitly configured in Java is a better solution because it is more powerful, Type-safe and refactoring-friendly. And when you need to assemble a bean very much, put it in an XML configuration file

Inconvenient to manage, using Java configuration just put all the javaconfig under one package and scan this Package.

2. Code Implementation

1.applicationcontext-service.xml Scan Javaconfig Pack

1 <  base-package= "com.taozhiye.JavaConfig"></Context:component-scan  >

　　

2.cdplayer.java

1  package com.taozhiye.JavaConfigTemp; 2 3  public Interface CDPlayer {4     5      public void Get (); 6 7 }

3.sgtpeppers.java

1  package com.taozhiye.JavaConfigTemp; 2 3  public class Implements CDPlayer {4    @Override5public     void  Get () {6         System.out.println ("sgtpeppers"); 7     }89 }

4.whitealbum.java

  1  package   com.taozhiye.JavaConfigTemp;   2   3  public  class  whitealbum implements   cdplayer {  4   5   @Override   6  public  void   get () {  7  System.out.println ("whitealbum"   8  }   9  10 } 

5.javaconfig.java need to scan the package of this file

1  packagecom.taozhiye.JavaConfig;2 3 Importorg.springframework.context.annotation.Bean;4 Importorg.springframework.context.annotation.Configuration;5 6 Importcom.taozhiye.JavaConfigTemp.CDPlayer;7 Importcom.taozhiye.JavaConfigTemp.SgtPeppers;8 Importcom.taozhiye.JavaConfigTemp.WhiteAlbum;9 Ten @Configuration one  public classJavaconfig { a      -@Bean (name = "cdplayer") -      publicCDPlayer get () { the         intChoice = (int) Math.floor (math.random ()); -System.out.println ("choice:" +choice); -         if(choice = = 0){ -             return Newsgtpeppers (); +}Else{ -             return Newwhitealbum (); +         } a     } at}

6.javaconfigaction.java

1  packagecom.taozhiye.controller;2 3 Importorg.springframework.beans.factory.annotation.Autowired;4 Importorg.springframework.stereotype.Controller;5 Importorg.springframework.web.bind.annotation.RequestMapping;6 Importorg.springframework.web.bind.annotation.ResponseBody;7 8 Importcom.taozhiye.JavaConfigTemp.CDPlayer;9 Ten  one @Controller a  public classjavaconfigaction { -      -@Autowired (required =false) the      publicCDPlayer cdplayer; -      -@RequestMapping ("getcdplayer") -      public@ResponseBody String getcdplayer () { + System.out.println (cdplayer); -         if(cdplayer!=NULL){ + Cdplayer.get (); a         } at         return"cdplayer"; -     } -}

This completes the explicit configuration in simple Java.

Spring assembly Bean (explicitly configured in Java)