Spring 学习（一）-----装配Bean

#装配Bean
### 一 自动装配Bean
####1) 用@componet+@Autowired+Spring 配置类名（指定 Spring 配置信息的来源）
<p>Printer.class
<pre><code>
package xuejun.printer;
public interface Printer {
    public void print();
}
</code></pre>




<p>JSONPrinter.class <font color="#DC143C">@Componet表示JSONPrinter类可以进行组装</font>
<pre><code>
package xuejun.printer;
import org.springframework.stereotype.Component;


@Component("jSONPrinter")
public class JSONPrinter implements Printer {
    public void print(){
        System.out.println("Json Output Printer");
    }
}
</code></pre>


<p>OutPutHelper.class <font color="#DC143C">@Componet表示OutPutHelper类可以进行组装,@Autowired声明要装载进来的类JSONPrinter</font>
<pre><code>
package xuejun.printer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component("outPutHelper")
public class OutPutHelper {
    Printer printer;
    @Autowired
    public OutPutHelper(Printer SONPrinter){
        this.printer = SONPrinter;
    }
    public void print(){
        printer.print();
    }
}
</code></pre>
<p>OutPutHelperConfig.class <font color="#DC143C">声明spring配置类</font>
<pre><code>
package xuejun.printer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@ComponentScan
public class OutPutHelperConfig {
      Printer printer;
      @Autowired
      public void OutPutHelper(Printer SONPrinter){
            this.printer = SONPrinter;
      }
      public void print(){
            printer.print();
      }
}
</code></pre>


<p>测试类
<pre><code>
package xuejun.output;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import xuejun.printer.OutPutHelper;
import xuejun.printer.OutPutHelperConfig;
import javax.annotation.Resource;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes=OutPutHelperConfig.class)
public class Output {
    @Resource OutPutHelper outPutHelper;
    @Test
    public  void test( )
    {
        outPutHelper.print();
    }
}</code></pre>
<p><font color="#DC143C">输出“Json Output Printer”</font>
####2) 用@componet+@Autowired+xml配置（指定 Spring 配置信息的来源）
#####第一步，将OutPutHelperConfig.class去掉；
#####第二步，新增xml配置；
#####第三步，更改测试类。
<p> <font color="#DC143C">在/resource/ApplicationContext/ 路径下新增spring-component.xml配置</font>
<p>测试类
<pre>
package xuejun.output;


import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import xuejun.printer.OutPutHelper;
import xuejun.printer.OutPutHelperConfig;
import javax.annotation.Resource;
@RunWith(SpringJUnit4ClassRunner.class)
<font color="#DC143C">@ContextConfiguration("/ApplicationContext/spring-component.xml")</font>
public class Output {
    @Resource OutPutHelper outPutHelper;
    @Test
    public  void test( )
        outPutHelper.print();     
    }
}
</pre>
<p><font color="#DC143C">输出“Json Output Printer”</font>
### 二 通过Java代码装配Bean


####用@bean+javaConfig,@Bean注解会告诉spring这个方法将返回一个对象，该对象注册为spring应用上下文中的bean。
#####1）OutPutHelper.class，<font color="#DC143C">支持构造函数</font>
<font color="#DC143C">把所有类的@componet和@Autowired都去掉</font>




<pre>
package xuejun.printer
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
public class OutPutHelper {
    Printer printer;
    private JSONPrinter outPutHelper;
    public <font color="#DC143C">OutPutHelper</font>(Printer SONPrinter){
        this.printer = SONPrinter;
    }
    public void print(){
        printer.print();
    }
}
</pre>
<p> OutPutHelperConfig.class
<pre>
package xuejun.printer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
@Configuration
public class OutPutHelperConfig {
      @Bean
      public JSONPrinter JSONPrinter(){
           return new JSONPrinter();
      }
      @Bean
      public OutPutHelper OutPutHelper(Printer jSONPrinter){
            return new OutPutHelper(jSONPrinter);
      }
}
</pre>
<p>测试类
<pre>
package xuejun.output;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import xuejun.printer.OutPutHelper;
import xuejun.printer.OutPutHelperConfig;
import javax.annotation.Resource;
@RunWith(SpringJUnit4ClassRunner.class)
<font color="#DC143C">@ContextConfiguration(classes = OutPutHelperConfig.class)</font>
public class Output {
    @Resource OutPutHelper outPutHelper;
    @Test
    public  void test( )
        outPutHelper.print();     
    }
}
</pre>
<p><font color="#DC143C">输出“Json Output Printer”</font>






### 二 通过xml装配Bean
<font color="#DC143C">把所有类的@componet和@Autowired都去掉</font>
#####1）OutPutHelper.class，<font color="#DC143C">支持setter与getter</font>
<pre>
package xuejun.printer
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
public class OutPutHelper {
    Printer printer;
    private JSONPrinter outPutHelper;
    public void <font color="#DC143C">setOutPutHelper</font>(Printer SONPrinter){
        this.printer = SONPrinter;
    }
    public void print(){
        printer.print();
    }
}
</pre>
<p> <font color="#DC143C">在/resource/ApplicationContext/ 路径下新增xml配置</font>
<p>测试类
<pre>
package xuejun.output;


import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import xuejun.printer.OutPutHelper;
import xuejun.printer.OutPutHelperConfig;
import javax.annotation.Resource;
@RunWith(SpringJUnit4ClassRunner.class)
<font color="#DC143C">@ContextConfiguration("/ApplicationContext/Spring-common.xml")</font>
public class Output {
    @Resource OutPutHelper outPutHelper;
    @Test
    public  void test( )
        outPutHelper.print();     
    }
}
</pre>
<p><font color="#DC143C">输出“Json Output Printer”</font>
<font color="#DC143C">把所有类的@componet和@Autowired都去掉</font>
#####2）OutPutHelper.class，<font color="#DC143C">支持构造函数</font>
<pre>
package xuejun.printer
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
public class OutPutHelper {
    Printer printer;
    private JSONPrinter outPutHelper;
    public <font color="#DC143C">OutPutHelper</font>(Printer SONPrinter){
        this.printer = SONPrinter;
    }
    public void print(){
        printer.print();
    }
}
</pre>
<p> <font color="#DC143C">在/resource/ApplicationContext/ 路径下新增xml配置，不同的是“property”换成了“constructor-arg”</font>
<p>测试类
<pre>
package xuejun.output;


import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import xuejun.printer.OutPutHelper;
import xuejun.printer.OutPutHelperConfig;
import javax.annotation.Resource;
@RunWith(SpringJUnit4ClassRunner.class)
<font color="#DC143C">@ContextConfiguration("/ApplicationContext/Spring-common.xml")</font>
public class Output {
    @Resource OutPutHelper outPutHelper;
    @Test
    public  void test( )
        outPutHelper.print();     
    }
}
</pre>
<p><font color="#DC143C">输出“Json Output Printer”</font>