我自己的1024开发工具之1024都没软件

在一个生命周期长的对象里面定义一个scope为request，或session的对象#

1. xml配置方式

proxy-target-class default=true使用CGlib进行代理; default=false 时使用JDK动态代理;

<!-- DefaultUserPreferences implements the UserPreferences interface --> <bean id="userPreferences" class="com.stuff.DefaultUserPreferences" scope="session"> <aop:scoped-proxy proxy-target-class="false"/> </bean> <bean id="userManager" class="com.stuff.UserManager"> <property name="userPreferences" ref="userPreferences"/> </bean> 

2. 注解方式

CGLIB 方式：@Scope(value="request", proxyMode= ScopedProxyMode.TARGET_CLASS)

JDK动态代理 方式：@Scope(value="request", proxyMode= ScopedProxyMode.INTERFACES)

util 标签#

未使用util标签时 注入 constant isolation

<bean id="..." class="..."> <property name="isolation"> <bean id="java.sql.Connection.TRANSACTION_SERIALIZABLE" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean" /> </property> </bean> 

使用util标签可以更加简洁

<bean id="..." class="..."> <property name="isolation"> <util:constant static-field="java.sql.Connection.TRANSACTION_SERIALIZABLE"/> </property> </bean> 

如果一个单例bean引用了原型bean，如何保证每次单例bean中的原型bean每次都是不一样的？#

方法一：lookup,通过lookup会自动去查找类型一样的bean进行注入；注意使用lookup的方法必须为抽象方法；

@Component @Scope(value = "prototype") public class AAA {} 
@Component
 public abstract class ControllerManager {
 
<span class="hljs-keyword">private AAA aaa;

<span class="hljs-meta">@Lookup
<span class="hljs-function"><span class="hljs-keyword">public <span class="hljs-keyword">abstract AAA <span class="hljs-title">createAAA<span class="hljs-params">() ;

<span class="hljs-function"><span class="hljs-keyword">public <span class="hljs-keyword">void <span class="hljs-title">test<span class="hljs-params">() {
    <span class="hljs-keyword">this.aaa = createAAA();
    System.err.println(<span class="hljs-keyword">this.getClass()+<span class="hljs-string">" "+<span class="hljs-keyword">this);
}
 
}
 

方法二：实现ApplicationContextAware拿到beanFactory对象，每次方法调用的时候都会获取到一个新的单例bean

<span class="hljs-meta">@Autowired field 注入为什么不用setter,getter方法？

  
  
  
 
   
<span class="hljs-meta">@Autowired先会按类型注入，如果有多个类型，则按照名字注入；
 
  
在源码中设置值是通过反射实现org.springframework.beans.DirectFieldAccessor.FieldPropertyHandler#setValue
<span class="hljs-meta">@Override
<span class="hljs-function"><span class="hljs-keyword">public <span class="hljs-keyword">void <span class="hljs-title">setValue<span class="hljs-params">(<span class="hljs-meta">@Nullable Object value) <span class="hljs-keyword">throws Exception {
	<span class="hljs-keyword">try {
		ReflectionUtils.makeAccessible(<span class="hljs-keyword">this.field);
		<span class="hljs-keyword">this.field.set(getWrappedInstance(), value);
	}
	<span class="hljs-keyword">catch (IllegalAccessException ex) {
		<span class="hljs-keyword">throw <span class="hljs-keyword">new InvalidPropertyException(getWrappedClass(), <span class="hljs-keyword">this.field.getName(),
				<span class="hljs-string">"Field is not accessible", ex);
	}
}
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></code></pre>
<h2 id="如果autowired接口有多个子实现类如何指定为特定的一个呢">如果<code>@Autowired</code>接口有多个子实现类，如何指定为特定的一个呢？<a class="esa-anchor" href="https://www.cnblogs.com/whalefall541/p/15640468.html#%E5%A6%82%E6%9E%9Cautowired%E6%8E%A5%E5%8F%A3%E6%9C%89%E5%A4%9A%E4%B8%AA%E5%AD%90%E5%AE%9E%E7%8E%B0%E7%B1%BB%E5%A6%82%E4%BD%95%E6%8C%87%E5%AE%9A%E4%B8%BA%E7%89%B9%E5%AE%9A%E7%9A%84%E4%B8%80%E4%B8%AA%E5%91%A2">#</a></h2>
<ol>
<li>在某一个子实现类上使用<code>@Primary</code>指定要注入的Bean为当前的bean</li>
</ol>
<pre><code class="language-java hljs hljsln ln-hide"><span class="hljs-meta">@Primary 
<span class="hljs-keyword">public <span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">ProtoBeanImpl <span class="hljs-keyword">implements <span class="hljs-title">ProtoBean{
}
</span></span></span></span></span></span></span></code></pre>
<pre><code class="language-java hljs hljsln ln-hide"><span class="hljs-meta">@Primary
<span class="hljs-meta">@Bean
<span class="hljs-function"><span class="hljs-keyword">public ProtoBeanImpl <span class="hljs-title">protoBean<span class="hljs-params">(){
    <span class="hljs-keyword">return <span class="hljs-keyword">new ProtoBeanImpl();
}
</span></span></span></span></span></span></span></span></code></pre>
<ol start="2">
<li>使用<code>@Qulifier("xxx")</code>注解 指定要注入的bean的类型</li>
</ol>
<pre><code class="language-java hljs hljsln ln-hide">	<span class="hljs-meta">@Qualifier("protoBeanImpl2")
    <span class="hljs-meta">@Autowired
    <span class="hljs-keyword">private ProtoBean bean;
</span></span></span></code></pre>
<pre><code class="language-java hljs hljsln ln-hide"><span class="hljs-meta">@Autowired
<span class="hljs-function"><span class="hljs-keyword">public <span class="hljs-title">SingleBean<span class="hljs-params">(<span class="hljs-meta">@Qualifier("protoBeanImpl2") ProtoBean proto) {
    <span class="hljs-keyword">this.protoBeanImpl2 = (ProtoBeanImpl2) proto;
}
</span></span></span></span></span></span></span></code></pre>
<ol start="3">
<li>使用@Bean上的<code>autowireCandidate = false</code>&nbsp;指定该bean 不会被其他类自动注入</li>
</ol>
<pre><code class="language-java hljs hljsln ln-hide"><span class="hljs-meta">@Bean(autowireCandidate = false)
<span class="hljs-function"><span class="hljs-keyword">public ProtoBeanImpl <span class="hljs-title">protoBean<span class="hljs-params">(){
    <span class="hljs-keyword">return <span class="hljs-keyword">new ProtoBeanImpl();
}
</span></span></span></span></span></span></span></code></pre>
<h2 id="构造器注入">构造器注入<a class="esa-anchor" href="https://www.cnblogs.com/whalefall541/p/15640468.html#%E6%9E%84%E9%80%A0%E5%99%A8%E6%B3%A8%E5%85%A5">#</a></h2>
<p>using constructor inject,do not need other annotation if all the properties is base type ,using<br />@ConstrutorProperties({"xxx","xxx",...}) to inject the value</p>
<ol>
<li>
<p>if just one constructor here ,need not&nbsp;<code>@Autowired</code></p>


</li>
<li>
<p>only one multi-argument constructor can be set&nbsp;<code>@Autowired(required = true)</code></p>


</li>
<li>
<p>if one more constructor are annotationed with&nbsp;<code>@Autowired(required = false)</code><br />The constructor with the greatest number of dependencies that can be satisfied<br />by matching beans in the Spring container will be chose</p>


</li>
<li>
<p>The @Autowired, @Inject, @Value, and @Resource annotations are handled by Spring<br />BeanPostProcessor implementations</p>


</li>


</ol>
<h2 id="使用aspectj注解进行aop配置好还是xml">使用AspectJ注解进行AOP配置好还是xml？<a class="esa-anchor" href="https://www.cnblogs.com/whalefall541/p/15640468.html#%E4%BD%BF%E7%94%A8aspectj%E6%B3%A8%E8%A7%A3%E8%BF%9B%E8%A1%8Caop%E9%85%8D%E7%BD%AE%E5%A5%BD%E8%BF%98%E6%98%AFxml"><br /></a></h2>
<p>使用xml配置时，将AOP配置分散了，一部分在xml中，一部分在后台的class类中。不符合DRY原则。</p>
<p>然而使用<code>@AspectJ</code>，则将整个AOP的配置放在一个配置类中，@AspectJ支持额外的实例模型更丰富的组合，是每个切面成为一个模型单元。<br />同时，@AspectJ 能被 Spring AOP 和AspectJ 解析，你可以使用AspectJ的语法去实现更加复杂的切面逻辑</p>
<h2 id="闭包-和-回调">闭包 和 回调<a class="esa-anchor" href="https://www.cnblogs.com/whalefall541/p/15640468.html#%E9%97%AD%E5%8C%85-%E5%92%8C-%E5%9B%9E%E8%B0%83"><br /></a></h2>
<div class="cnblogs_code">
<pre><span style="color: #000000;">
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</span></pre>
</div>
<p>闭包:闭包和匿名函数经常被用作同义词。但严格来说，匿名函数就是字面意义上没有被赋予名称的函数，而闭包则实际上是一个函数的实例，也就是说它是存在于内存里的某个结构体。如果从实现上来看的话，匿名函数如果没有捕捉自由变量，那么它其实可以被实现为一个函数指针，或者直接内联到调用点，如果它捕捉了自由变量那么它将是一个闭包；而闭包则意味着同时包括函数指针和环境两个关键元素。<br />[Closure Sample][Closure Sample]</p>