Spring 5 中文解析核心篇 -IoC 容器之依赖关系

 public class SimpleMovieLister {
  
      // the SimpleMovieLister has a dependency on a MovieFinder
      private MovieFinder movieFinder;
  
      //构造函数注入MovieFinder对象
      public SimpleMovieLister(MovieFinder movieFinder) {
          this.movieFinder = movieFinder;
      }
  
      // business logic that actually uses the injected MovieFinder is omitted...
  }

  package x.y;
  
  public class ThingOne {
  
      public ThingOne(ThingTwo thingTwo, ThingThree thingThree) {
          // ...
      }
  }

  <beans>
      <bean id="beanOne" class="x.y.ThingOne">
          <constructor-arg ref="beanTwo"/>
          <constructor-arg ref="beanThree"/>
      </bean>
  
      <bean id="beanTwo" class="x.y.ThingTwo"/>
  
      <bean id="beanThree" class="x.y.ThingThree"/>
  </beans>

 package examples;
  
  public class ExampleBean {
  
      // Number of years to calculate the Ultimate Answer
      private int years;
  
      // The Answer to Life, the Universe, and Everything
      private String ultimateAnswer;
  
      public ExampleBean(int years, String ultimateAnswer) {
          this.years = years;
          this.ultimateAnswer = ultimateAnswer;
      }
  }

  <bean id="exampleBean" class="examples.ExampleBean">
      <constructor-arg type="int" value="7500000"/>
      <constructor-arg type="java.lang.String" value="42"/>
  </bean>

  <bean id="exampleBean" class="examples.ExampleBean">
      <!--指定第一个参数-->
      <constructor-arg index="0" value="7500000"/>
      <!--指定第二个参数-->
      <constructor-arg index="1" value="42"/>
  </bean>

  <bean id="exampleBean" class="examples.ExampleBean">
       <!--指定构造函数参数-->
      <constructor-arg name="years" value="7500000"/>
      <constructor-arg name="ultimateAnswer" value="42"/>
  </bean>

package examples;
  
  public class ExampleBean {
  
      // Fields omitted
      @ConstructorProperties({"years", "ultimateAnswer"})
      public ExampleBean(int years, String ultimateAnswer) {
          this.years = years;
          this.ultimateAnswer = ultimateAnswer;
      }
  }

 public class SimpleMovieLister {
  
      // the SimpleMovieLister has a dependency on the MovieFinder
      private MovieFinder movieFinder;
  
      // 通过Setter进行注入
      public void setMovieFinder(MovieFinder movieFinder) {
          this.movieFinder = movieFinder;
      }
  
      // business logic that actually uses the injected MovieFinder is omitted...
  }

<bean id="exampleBean" class="examples.ExampleBean">
      <!-- 属性注入：依赖一个bean -->
      <property name="beanOne">
          <ref bean="anotherExampleBean"/>
      </property>
      <!-- 属性注入：依赖一个bean-->
      <property name="beanTwo" ref="yetAnotherBean"/>
      <!-- 属性值填充-->
      <property name="integerProperty" value="1"/>
  </bean>
  <bean id="anotherExampleBean" class="examples.AnotherBean"/>
  <bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

 public class ExampleBean {
  
      private AnotherBean beanOne;
  
      private YetAnotherBean beanTwo;
  
      private int i;
  
      // 指定属性需要注入bean类型
      public void setBeanOne(AnotherBean beanOne) {
          this.beanOne = beanOne;
      }
  
     // 指定属性需要注入bean类型
      public void setBeanTwo(YetAnotherBean beanTwo) {
          this.beanTwo = beanTwo;
      }
  
      public void setIntegerProperty(int i) {
          this.i = i;
      }
  }

  <bean id="exampleBean" class="examples.ExampleBean">
      <!-- 构造函数注入bean  anotherExampleBean-->
      <constructor-arg>
          <ref bean="anotherExampleBean"/>
      </constructor-arg>
      <!-- 构造函数注入bean yetAnotherBean-->
      <constructor-arg ref="yetAnotherBean"/>
      <constructor-arg type="int" value="1"/>
  </bean>
  <bean id="anotherExampleBean" class="examples.AnotherBean"/>
  <bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

public class ExampleBean {
  
      private AnotherBean beanOne;
  
      private YetAnotherBean beanTwo;
  
      private int i;
  
    //需要在构造函数中声明需要依赖的类型定义
      public ExampleBean(
          AnotherBean anotherBean, YetAnotherBean yetAnotherBean, int i) {
          this.beanOne = anotherBean;
          this.beanTwo = yetAnotherBean;
          this.i = i;
      }
  }

  <bean id="exampleBean" class="examples.ExampleBean" factory-method="createInstance">    <constructor-arg ref="anotherExampleBean"/>      <constructor-arg ref="yetAnotherBean"/>    <constructor-arg value="1"/>  </bean>    <bean id="anotherExampleBean" class="examples.AnotherBean"/>  <bean id="yetAnotherBean" class="examples.YetAnotherBean"/>

public class ExampleBean {
      // a private constructor
    private ExampleBean(...) {
          ...
      }
  
      //静态工厂方法
      public static ExampleBean createInstance (
          AnotherBean anotherBean, YetAnotherBean yetAnotherBean, int i) {
  
          ExampleBean eb = new ExampleBean (...);
          // some other operations...
          return eb;
      }
  }

 <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
      <!-- results in a setDriverClassName(String) call -->
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url" value="jdbc:mysql://localhost:3306/mydb"/>
      <property name="username" value="root"/>
      <property name="password" value="masterkaoli"/>
  </bean> <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
      <!-- results in a setDriverClassName(String) call -->
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url" value="jdbc:mysql://localhost:3306/mydb"/>
      <property name="username" value="root"/>
      <property name="password" value="masterkaoli"/>
  </bean>

 <beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:p="http://www.springframework.org/schema/p"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
      https://www.springframework.org/schema/beans/spring-beans.xsd">
  
     <!--使用p命名空间 注意： xmlns:p="http://www.springframework.org/schema/p -->
      <bean id="myDataSource" class="org.apache.commons.dbcp.BasicDataSource"
          destroy-method="close"
          p:driverClassName="com.mysql.jdbc.Driver"
          p:url="jdbc:mysql://localhost:3306/mydb"
          p:username="root"
          p:password="masterkaoli"/>
  
  </beans>

<bean id="mappings"
      class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
      <!-- java.util.Properties类型配置 -->
      <property name="properties">
          <value>
              jdbc.driver.className=com.mysql.jdbc.Driver
              jdbc.url=jdbc:mysql://localhost:3306/mydb
          </value>
      </property>
  </bean>

 <bean id="theTargetBean" class="..."/>
  <bean id="theClientBean" class="...">
      <property name="targetName">
          <idref bean="theTargetBean"/>
      </property>
  </bean>

  <bean id="theTargetBean" class="..." />  <bean id="client" class="...">      <property name="targetName" value="theTargetBean"/>  </bean>

 <bean id="userService" class="com.liyong.ioccontainer.service.UserService"> 
          <!--属性注入 保存一种方式就可以-->
          <property name="bookService">
              <ref bean="bookService"/>
          </property>
      </bean>

   <!--在父容器上下文-->
  <bean id="accountService" class="com.something.SimpleAccountService">
      <!-- insert dependencies as required as here -->
  </bean>

<!-- 在子容器上下文 -->
   <!-- 产生一个代理bean，bean name is the same as the parent bean -->
  <bean id="accountService"
      class="org.springframework.aop.framework.ProxyFactoryBean">
      <property name="target">
          <ref parent="accountService"/> 
        <!-- notice how we refer to the parent bean -->
      </property>
      <!-- insert other configuration and dependencies as required here -->
  </bean>

 <!-- 外部bean定义 -->
  <bean id="outer" class="...">
      <!-- instead of using a reference to a target bean, simply define the target bean inline -->
      <property name="target">
        <!-- 内部bean定义 -->
          <bean class="com.example.Person"> 
              <property name="name" value="Fiona Apple"/>
              <property name="age" value="25"/>
          </bean>
      </property>
  </bean>

<bean id="moreComplexObject" class="example.ComplexObject">
      <!-- adminEmails属性为Properties类型。 results in a setAdminEmails(java.util.Properties) call -->
      <property name="adminEmails">
          <props>
              <prop key="administrator">administrator@example.org</prop>
              <prop key="support">support@example.org</prop>
              <prop key="development">development@example.org</prop>
          </props>
      </property>
      <!--someList属性为java.util.List类型。 results in a setSomeList(java.util.List) call -->
      <property name="someList">
          <list>
              <value>a list element followed by a reference</value>
              <ref bean="myDataSource" />
          </list>
      </property>
      <!--someMap属性类型为：java.util.Map。 results in a setSomeMap(java.util.Map) call -->
      <property name="someMap">
          <map>
              <entry key="an entry" value="just some string"/>
              <entry key ="a ref" value-ref="myDataSource"/>
          </map>
      </property>
      <!--someSet属性类型为：java.util.Set。 results in a setSomeSet(java.util.Set) call -->
      <property name="someSet">
          <set>
              <value>just some string</value>
              <ref bean="myDataSource" />
          </set>
      </property>
  </bean>

 bean | ref | idref | list | set | map | props | value | null

 <beans>
      <bean id="parent" abstract="true" class="example.ComplexObject">
          <property name="adminEmails">
              <props>
                  <prop key="administrator">administrator@example.com</prop>
                  <prop key="support">support@example.com</prop>
              </props>
          </property>
      </bean>
      <bean id="child" parent="parent">
          <property name="adminEmails">
              <!-- the merge is specified on the child collection definition -->
              <props merge="true">
                  <prop key="sales">sales@example.com</prop>
                  <prop key="support">support@example.co.uk</prop>
              </props>
          </property>
      </bean>
  <beans>

administrator=administrator@example.com
  sales=sales@example.com
  support=support@example.co.uk

 public class SomeClass {
  
      private Map<String, Float> accounts;
  
      public void setAccounts(Map<String, Float> accounts) {
          this.accounts = accounts;
      }
  }

  <beans>
      <bean id="something" class="x.y.SomeClass">
          <property name="accounts">
              <map>
                  <entry key="one" value="9.99"/>
                  <entry key="two" value="2.75"/>
                  <entry key="six" value="3.99"/>
              </map>
          </property>
      </bean>
  </beans>

 <bean class="ExampleBean">
      <property name="email" value=""/>
  </bean>

 exampleBean.setEmail("");

 <bean class="ExampleBean">
      <property name="email">
          <null/>
      </property>
  </bean>

 exampleBean.setEmail(null);

<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:p="http://www.springframework.org/schema/p"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
          https://www.springframework.org/schema/beans/spring-beans.xsd">
  
      <bean name="classic" class="com.example.ExampleBean">
          <property name="email" value="someone@somewhere.com"/>
      </bean>
  
      <bean name="p-namespace" class="com.example.ExampleBean"
          p:email="someone@somewhere.com"/>
  </beans>

 <beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:p="http://www.springframework.org/schema/p"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
          https://www.springframework.org/schema/beans/spring-beans.xsd">
  
      <bean name="john-classic" class="com.example.Person">
          <property name="name" value="John Doe"/>
          <property name="spouse" ref="jane"/>
      </bean>
  
      <bean name="john-modern"
          class="com.example.Person"
          p:name="John Doe"
          p:spouse-ref="jane"/>
  
      <bean name="jane" class="com.example.Person">
          <property name="name" value="Jane Doe"/>
      </bean>
  </beans>

 <beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      xmlns:c="http://www.springframework.org/schema/c"
      xsi:schemaLocation="http://www.springframework.org/schema/beans
          https://www.springframework.org/schema/beans/spring-beans.xsd">
  
      <bean id="beanTwo" class="x.y.ThingTwo"/>
      <bean id="beanThree" class="x.y.ThingThree"/>
  
      <!-- 传统声明可选参数 -->
      <bean id="beanOne" class="x.y.ThingOne">
          <constructor-arg name="thingTwo" ref="beanTwo"/>
          <constructor-arg name="thingThree" ref="beanThree"/>
          <constructor-arg name="email" value="something@somewhere.com"/>
      </bean>
  
      <!-- c-namespace声明参数名称 -->
      <bean id="beanOne" class="x.y.ThingOne" c:thingTwo-ref="beanTwo"
          c:thingThree-ref="beanThree" c:email="something@somewhere.com"/>
  
  </beans>

 <!-- c-namespace index declaration -->
  <bean id="beanOne" class="x.y.ThingOne" c:0-ref="beanTwo" c:1-ref="beanThree"
      c:_2="something@somewhere.com"/>

 <bean id="something" class="things.ThingOne">
      <property name="fred.bob.sammy" value="123" />
  </bean>

 <!--beanOne依赖manager-->
  <bean id="beanOne" class="ExampleBean" depends-on="manager"/>
  <bean id="manager" class="ManagerBean" />

<!--beanOne依赖manager,accountDao-->
  <bean id="beanOne" class="ExampleBean" depends-on="manager,accountDao">
      <property name="manager" ref="manager" />
  </bean>
  
  <bean id="manager" class="ManagerBean" />
  <bean id="accountDao" class="x.y.jdbc.JdbcAccountDao" />

<!--设置bean延迟初始化 注意：Spring中的bean默认是单例的--><bean id="lazy" class="com.something.ExpensiveToCreateBean" lazy-init="true"/><bean name="not.lazy" class="com.something.AnotherBean"/>

<beans default-lazy-init="true">    <!-- no beans will be pre-instantiated... --></beans>

package fiona.apple;
// Spring-API importsimport org.springframework.beans.BeansException;import org.springframework.context.ApplicationContext;import org.springframework.context.ApplicationContextAware;
public class CommandManager implements ApplicationContextAware {
    private ApplicationContext applicationContext;
    public Object process(Map commandState) {        // grab a new instance of the appropriate Command        Command command = createCommand();        // set the state on the (hopefully brand new) Command instance        command.setState(commandState);        return command.execute();    }
    protected Command createCommand() {        // 通过从容器获取bean        return this.applicationContext.getBean("command", Command.class);    }
    public void setApplicationContext(            ApplicationContext applicationContext) throws BeansException {      //容器注入ApplicationContext        this.applicationContext = applicationContext;    }}

package fiona.apple;
  
  // 没有Spring的依赖!
  public abstract class CommandManager {
  
      public Object process(Object commandState) {
          // grab a new instance of the appropriate Command interface
          Command command = createCommand();
          // set the state on the (hopefully brand new) Command instance
          command.setState(commandState);
          return command.execute();
      }
  
      // okay... but where is the implementation of this method?
      protected abstract Command createCommand();
  }

 <public|protected> [abstract] <return-type> theMethodName(no-arguments);

  <!-- a stateful bean deployed as a prototype (non-singleton) -->
  <bean id="myCommand" class="fiona.apple.AsyncCommand" scope="prototype">
      <!-- inject dependencies here as required -->
  </bean>
  
  <!-- commandProcessor uses statefulCommandHelper -->
  <bean id="commandManager" class="fiona.apple.CommandManager">
      <lookup-method name="createCommand" bean="myCommand"/>
  </bean>

 public abstract class CommandManager {
  
      public Object process(Object commandState) {
          Command command = createCommand();
          command.setState(commandState);
          return command.execute();
      }
  
      //指定名称查找，在容器中查找
      @Lookup("myCommand")
      protected abstract Command createCommand();
  }

 public abstract class CommandManager {
  
      public Object process(Object commandState) {
          MyCommand command = createCommand();
          command.setState(commandState);
          return command.execute();
      }
  
      //没有指定名称查找，通过查找方法的MyCommand类型去容器查找
      @Lookup
      protected abstract MyCommand createCommand();
  }

 public class MyValueCalculator {
  
      public String computeValue(String input) {
          // some real code...
      }
  
      // some other methods...
  }

  public class ReplacementComputeValue implements MethodReplacer {
  
      public Object reimplement(Object o, Method m, Object[] args) throws Throwable {
          // get the input value, work with it, and return a computed result
          String input = (String) args[0];
          ...
          return ...;
      }
  }

  <bean id="myValueCalculator" class="x.y.z.MyValueCalculator">
      <!-- 替换方法 -->
      <replaced-method name="computeValue" replacer="replacementComputeValue">
          <arg-type>String</arg-type>
      </replaced-method>
  </bean>
  
  <bean id="replacementComputeValue" class="a.b.c.ReplacementComputeValue"/>

  java.lang.String
  String
  Str