spring中使用autowire特性时注意

spring中可以只用autowire="byName"或者"byType"来提供自动注入。但是大家有一点还需要注意，那就是它不支持基本数据类型(String，int，long等)的自动注入。例如
JAVA类：

1. publicclassTestBean{
2. privateStringname;
3. privateLongage;
4. privateStringfullName;
5. privateTestBean2testBean2;
7. publicvoidsetTestBean2(TestBean2testBean2){
8. this.testBean2=testBean2;
9. }
10. publicTestBean2getTestBean2(){
11. returntestBean2;
12. }
13. publicvoidsetFullName(StringfullName){
14. this.fullName=fullName;
15. }
16. publicStringgetFullName(){
17. returnfullName;
18. }
20. publicvoidsetAge(Longage){
21. this.age=age;
22. }
24. publicLonggetAge(){
25. returnage;
26. }
28. publicvoidsetName(Stringname){
29. this.name=name;
30. }
32. publicStringgetName(){
33. returnname;
34. }
35. }

JAVA类2：

1. publicclassTestBean2{
2. publicStringgetString(){
3. return"testB";
4. }
5. }

配置文件：

1. <beansdefault-autowire="byName">
2. <!--login-->
3. <beanid="testBean"class="TestBean">
4. <propertyname="fullName">
5. <value>fullName</value>
6. </property>
7. </bean>
8. <beanid="name"class="java.lang.String">
9. <constructor-arg>
10. <value>hell</value>
11. </constructor-arg>
12. </bean>
13. <beanid="age"class="java.lang.Long">
14. <constructor-arg>
15. <value>20</value>
16. </constructor-arg>
17. </bean>
18. <beanid="testBean2"class="TestBean2"/>
19. </beans>

测试类：

1. importorg.springframework.context.support.ClassPathXmlApplicationContext;
3. publicclassTest{
4. publicstaticvoidmain(String[]args){
5. ClassPathXmlApplicationContextt=newClassPathXmlApplicationContext(
6. "test.xml");
7. TestBeanbean=(TestBean)t.getBean("testBean");
8. System.out.println("name:"+bean.getName()+"age:"+bean.getAge()
9. +"fullName:"+bean.getFullName()+"testBean2"
10. +bean.getTestBean2().getString());
11. }
13. }

输出的结果是：
name:null age:null fullName :fullName testBean2:testB


spring源码中排除基本类型的代码（源码来自：org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory类）在：

1. protectedString[]unsatisfiedNonSimpleProperties(AbstractBeanDefinitionmbd,BeanWrapperbw){
2. Setresult=newTreeSet();
3. PropertyValuespvs=mbd.getPropertyValues();
4. PropertyDescriptor[]pds=bw.getPropertyDescriptors();
5. for(inti=0;i<pds.length;i++){
6. if(pds[i].getWriteMethod()!=null&&!isExcludedFromDependencyCheck(pds[i])&&
7. !pvs.contains(pds[i].getName())&&!BeanUtils.isSimpleProperty(pds[i].getPropertyType())){
8. result.add(pds[i].getName());
9. }
10. }
11. returnStringUtils.toStringArray(result);
12. }

请注意以上紫色部分。而这个 unsatisfiedNonSimpleProperties方法都是在自动注入时调用。所以基本类型不会被注入。