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：
1 /** 2 * 3 */ 4 package com.hlcui.dao; 5 6 /** 7 * @author Administrator 8 * 9 */ 10 public class MessageBean { 11 private String name; 12 13 private int age; 14 15 private double salary; 16 17 public String getName() { 18 return name; 19 } 20 21 public void setName(String name) { 22 this.name = name; 23 } 24 25 public int getAge() { 26 return age; 27 } 28 29 public void setAge(int age) { 30 this.age = age; 31 } 32 33 public double getSalary() { 34 return salary; 35 } 36 37 public void setSalary(double salary) { 38 this.salary = salary; 39 } 40 41 public String execute() { 42 System.out.println("name=" + name + "\nage=" + age 43 + "\nsalary=" + salary); 44 return "success"; 45 } 46 47 }
b. 在spring容器配置文件中配置MessageBean对象核心代码：
1 <!-- 配置MessageBean对象 --> 2 <bean id="messageBean" class="com.hlcui.dao.MessageBean"> 3 <property name="name" value="Jack"></property> 4 <property name="age" value="27"></property> 5 <property name="salary" value="12000"></property> 6 </bean>
或者将value元素作为property元素的子元素，效果是一样的
1 <bean id="messageBean" class="com.hlcui.dao.MessageBean"> 2 <property name="name"> 3 <value>Tom</value> 4 </property> 5 <property name="age"> 6 <value>27</value> 7 </property> 8 <property name="salary"> 9 <value>12000</value> 10 </property> 11 </bean>
c. 运行测试方法
1 @Test 2 public void testBaseInject(){ 3 ApplicationContext ac = getApplicationContext(); 4 MessageBean mb = ac.getBean("messageBean", MessageBean.class); 5 mb.execute(); 6 }
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：
1 /** 2 * 3 */ 4 package com.hlcui.dao; 5 6 import java.util.Iterator; 7 import java.util.List; 8 import java.util.Map; 9 import java.util.Properties; 10 import java.util.Set; 11 import java.util.Map.Entry; 12 13 /** 14 * @author Administrator 15 * 16 */ 17 public class MessageBean { 18 private List<String> someList; 19 private Set<Integer> someSet; 20 private Map<String,Object> someMap; 21 private Properties props; 22 23 private String name; 24 25 private int age; 26 27 private double salary; 28 29 30 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; 60 } 61 62 public String getName() { 63 return name; 64 } 65 66 public void setName(String name) { 67 this.name = name; 68 } 69 70 public int getAge() { 71 return age; 72 } 73 74 public void setAge(int age) { 75 this.age = age; 76 } 77 78 public double getSalary() { 79 return salary; 80 } 81 82 public void setSalary(double salary) { 83 this.salary = salary; 84 } 85 86 public String execute() { 87 System.out.println("name=" + name + "\nage=" + age 88 + "\nsalary=" + salary); 89 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 } 108 return "success"; 109 } 110 111 }
配置文件修改如下：
1 <bean id="messageBean" class="com.hlcui.dao.MessageBean"> 2 <property name="name"> 3 <value>Tom</value> 4 </property> 5 <property name="age"> 6 <value>27</value> 7 </property> 8 <property name="salary"> 9 <value>12000</value> 10 </property> 11 <property name="someList"> 12 <list> 13 <value>aaaaList</value> 14 <value>bbbbList</value> 15 <value>ccccList</value> 16 </list> 17 </property> 18 <property name="someSet"> 19 <set> 20 <value>111</value> 21 <value>222</value> 22 <value>333</value> 23 </set> 24 </property> 25 <property name="someMap"> 26 <map> 27 <entry key="1" value="java"></entry> 28 <entry key="2" value="c++"></entry> 29 <entry key="3" value="c#"></entry> 30 </map> 31 </property> 32 <property name="props"> 33 <props> 34 <prop key="username">root</prop> 35 <prop key="password">root</prop> 36 </props> 37 </property> 38 </bean> 39
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：
1 <util:list id="someList"> 2 <value>aaaaList</value> 3 <value>bbbbList</value> 4 <value>ccccList</value> 5 </util:list> 6 <util:set id="someSet"> 7 <value>111</value> 8 <value>222</value> 9 <value>333</value> 10 </util:set> 11 <util:map id="someMap"> 12 <entry key="1" value="java"></entry> 13 <entry key="2" value="c++"></entry> 14 <entry key="3" value="c#"></entry> 15 </util:map> 16 <util:properties id="props"> 17 <prop key="username">root</prop> 18 <prop key="password">root</prop> 19 </util:properties> 20 <bean id="messageBean" class="com.hlcui.dao.MessageBean"> 21 <property name="name"> 22 <value>Tom</value> 23 </property> 24 <property name="age"> 25 <value>27</value> 26 </property> 27 <property name="salary"> 28 <value>12000</value> 29 </property> 30 <property name="someList" ref="someList"></property> 31 <property name="someSet" ref="someSet"></property> 32 <property name="someMap" ref="someMap"></property> 33 <property name="props" ref="props"></property> 34 </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：
1 name=Jack 2 age=30 3 salary=15000
2：在spring容器配置文件中加载配置文件
1 <!-- 加载配置文件user.properties --> 2 <util:properties id="user" location="classpath:user.properties"/> 3
1 <!-- 配置MessageBean对象 --> 2 <bean id="messageBean" class="com.hlcui.dao.MessageBean"> 3 <property name="name" value="#{user.name}"></property> 4 <property name="age" value="#{user.age}"></property> 5 <property name="salary" value="#{user.salary}"></property> 6 </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
1 <!-- 配置MessageBean对象 --> 2 <bean id="messageBean" class="com.hlcui.dao.MessageBean"> 3 <property name="name"> 4 <null/> 5 </property> 6 <property name="age" value="#{user.age}"></property> 7 <property name="salary" value="#{user.salary}"></property> 8 </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！
