Spring学习总结四——SpringIOC容器四

一：spring容器给bean对象注入属性值

1：注入基本属性值

a. 创建MessageBean类：

 /**
  *
  */
 package com.hlcui.dao;

 /**
  * @author Administrator
  *
  */
 public class MessageBean {
     private String name;

     private int age;

     private double salary;

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public double getSalary() {
         return salary;
     }

     public void setSalary(double salary) {
         this.salary = salary;
     }

     public String execute() {
         System.out.println("name=" + name + "\nage=" + age
                 + "\nsalary=" + salary);
         return "success";
     }

 }

b. 在spring容器配置文件中配置MessageBean对象核心代码：

 <!-- 配置MessageBean对象 -->
     <bean id="messageBean" class="com.hlcui.dao.MessageBean">
         <property name="name" value="Jack"></property>
         <property name="age" value="27"></property>
         <property name="salary" value="12000"></property>
     </bean>

或者将value元素作为property元素的子元素，效果是一样的

 <bean id="messageBean" class="com.hlcui.dao.MessageBean">
         <property name="name">
             <value>Tom</value>
         </property>
         <property name="age">
             <value>27</value>
         </property>
         <property name="salary">
             <value>12000</value>
         </property>
     </bean>

c. 运行测试方法

 @Test
     public void testBaseInject(){
         ApplicationContext ac = getApplicationContext();
         MessageBean mb = ac.getBean("messageBean", MessageBean.class);
         mb.execute();
     }

通过运行结果可知属性值已经注入到对象中，这种方式在前面已经总结过，就是setter注入。

2：注入集合属性值(List、Set、Map、Properties)

修改MessageBean类：

 /**
  *
  */
 package com.hlcui.dao;

 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
 import java.util.Map.Entry;

 /**
  * @author Administrator
  *
  */
 public class MessageBean {
     private List<String> someList;
 19     private Set<Integer> someSet;
 20     private Map<String,Object> someMap;
 21     private Properties props;

     private String name;

     private int age;

     private double salary;

     public List<String> getSomeList() {
 31         return someList;
 32     }
 33
 34     public void setSomeList(List<String> someList) {
 35         this.someList = someList;
 36     }
 37
 38     public Set<Integer> getSomeSet() {
 39         return someSet;
 40     }
 41
 42     public void setSomeSet(Set<Integer> someSet) {
 43         this.someSet = someSet;
 44     }
 45
 46     public Map<String, Object> getSomeMap() {
 47         return someMap;
 48     }
 49
 50     public void setSomeMap(Map<String, Object> someMap) {
 51         this.someMap = someMap;
 52     }
 53
 54     public Properties getProps() {
 55         return props;
 56     }
 57
 58     public void setProps(Properties props) {
 59         this.props = props;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public int getAge() {
         return age;
     }

     public void setAge(int age) {
         this.age = age;
     }

     public double getSalary() {
         return salary;
     }

     public void setSalary(double salary) {
         this.salary = salary;
     }

     public String execute() {
         System.out.println("name=" + name + "\nage=" + age
                 + "\nsalary=" + salary);
         System.out.println("--------List集合结果--------");
 90         for(String str:someList){
 91             System.out.println(str);
 92         }
 93         System.out.println("--------Set集合结果--------");
 94         for(Iterator<Integer> it = someSet.iterator();it.hasNext();){
 95             System.out.println(it.next());
 96         }
 97         System.out.println("-------Map集合结果--------");
 98         for(Entry<String, Object> entry:someMap.entrySet()){
 99             String key = entry.getKey();
100             String value = (String) entry.getValue();
101             System.out.println(key+"=="+value);
102         }
103         System.out.println("-------Properties结果------");
104         for(Object obj : props.keySet()){
105             String value = props.getProperty((String) obj);
106             System.out.println(obj+"=="+value);
107         }
         return "success";
     }

 }

配置文件修改如下：

 <bean id="messageBean" class="com.hlcui.dao.MessageBean">
         <property name="name">
             <value>Tom</value>
         </property>
         <property name="age">
             <value>27</value>
         </property>
         <property name="salary">
             <value>12000</value>
         </property>
         <property name="someList">
             <list>
                 <value>aaaaList</value>
                 <value>bbbbList</value>
                 <value>ccccList</value>
             </list>
         </property>
         <property name="someSet">
             <set>
                 <value>111</value>
                 <value>222</value>
                 <value>333</value>
             </set>
         </property>
         <property name="someMap">
             <map>
                 <entry key="1" value="java"></entry>
                 <entry key="2" value="c++"></entry>
                 <entry key="3" value="c#"></entry>
             </map>
         </property>
         <property name="props">
             <props>
                 <prop key="username">root</prop>
                 <prop key="password">root</prop>
             </props>
         </property>
     </bean>
     

运行测试方法：

从结果可以看出，参数注入成功！！！

3：引用方式注入集合属性

修改配置文件内容如下：

 <util:list id="someList">
         <value>aaaaList</value>
         <value>bbbbList</value>
         <value>ccccList</value>
     </util:list>
     <util:set id="someSet">
         <value>111</value>
         <value>222</value>
         <value>333</value>
     </util:set>
     <util:map id="someMap">
         <entry key="1" value="java"></entry>
         <entry key="2" value="c++"></entry>
         <entry key="3" value="c#"></entry>
     </util:map>
     <util:properties id="props">
         <prop key="username">root</prop>
         <prop key="password">root</prop>
     </util:properties>
     <bean id="messageBean" class="com.hlcui.dao.MessageBean">
         <property name="name">
             <value>Tom</value>
         </property>
         <property name="age">
             <value>27</value>
         </property>
         <property name="salary">
             <value>12000</value>
         </property>
         <property name="someList" ref="someList"></property>
         <property name="someSet" ref="someSet"></property>
         <property name="someMap" ref="someMap"></property>
         <property name="props" ref="props"></property>
 </beans>

运行测试方法：

和之前的效果是一样的，只不过这样配置更加明了！

二：利用spring表达式注入属性值

1：在src下添加文件user.properties,内容如下：

 name=Jack
 age=30
 salary=15000

2：在spring容器配置文件中加载配置文件

 <!-- 加载配置文件user.properties -->
     <util:properties id="user" location="classpath:user.properties"/>
     

 <!-- 配置MessageBean对象 -->
     <bean id="messageBean" class="com.hlcui.dao.MessageBean">
         <property name="name" value="#{user.name}"></property>
         <property name="age" value="#{user.age}"></property>
         <property name="salary" value="#{user.salary}"></property>
     </bean>

3：运行测试方法

通过结果可知spring表达式注入成功！

三：spring注入空值

1：修改配置文件

 <!-- 配置MessageBean对象 -->
     <bean id="messageBean" class="com.hlcui.dao.MessageBean">
         <property name="name">
             <null/>
         </property>
         <property name="age" value="#{user.age}"></property>
         <property name="salary" value="#{user.salary}"></property>
     </bean>

2：运行测试方法

空值注入成功，只有引用数据类型才可以注入空值！