Detailed introduction to Spring

Detailed introduction to Spring (1) https://www.cnblogs.com/jichi/p/10165538.html

1. set method injection

<bean name="user" > <property name="name" value="Xiao Ming"></property> <property name="age" value="18"></property> </bean>

2. Construction method injection

<bean name="user" > <constructor-arg name="name" value="Xiaohong" ></constructor-arg> <constructor-arg name="age" value="50"></constructor-arg> </bean>

3. p namespace injection

xmlns:p="http://www.springframework.org/schema/p"

<bean name="user" p:name="Xiao Bai" p:age="10"></bean>

4. spel expression injection

<bean name="user"> <property name="name" value="Xiaohong"></property> <property name="age" value="18"></property> </bean> <bean name="user1"> <property name="name" value="#"></property> <property name="age" value="#"></property> </bean>

public class Collection { public String[] arr; public List<String> list; public Map<String,Object> map; public Properties props; public String[] getArr() { return arr; } public void setArr(String[] arr) { this.arr = arr; } public List<String> getList() { return list; } public void setList(List<String> list) { this.list = list; } public Map<String, Object> getMap() { return map; } public void setMap(Map<String, Object> map) { this.map = map; } public Properties getProps() { return props; } public void setProps(Properties props) { this.props = props; } @Override public String toString() { return "Collection [arr=" + Arrays.toString(arr) + ", list=" + list + ", map=" + map + ", props=" + props + "]"; } }

1. Array type injection

<bean name="collect"> <property name="arr"> <array> <value>xiaohei</value> <value>xiaobai</value> </array> </property> </bean>

2. list type injection

<bean name="collect"> <property name="list"> <list> <value>xiaohei</value> <value>xiaobai</value> </list> </property> </bean>

3. map type injection

<bean name="collect"> <property name="map"> <map> <entry key="name" value="xiaohei"></entry> <entry key="age" value="18"></entry> </map> </property> </bean>

4. properties type injection

<bean name="collect"> <property name="props"> <props> <prop key="name">xiaohei</prop> <prop key="age">18</prop> </props> </property> </bean>

Configure in web.xml.

<listener> <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class> </listener>

<context-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:applicationContext.xml</param-value> </context-param>

Method 1:

ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext1.xml","applicationContext2.xml")

Mode two:

<import resource="applicationContext.xml"></import>

1. Enable annotation scanning

<context:component-scan base-package="com.jichi.entity"></context:component-scan>

Scan for annotations in all classes under com.jichi.entity.

2. Add notes to the class

@Component public class User { }

1, @ composet, @ Controller, @ Service, @ Repository are four component annotations that act on the class. There is no difference between the four notes, just for convenience.

2. The @ Scope annotation works on the class.

@Scope(scopeName="singleton") //Singleton mode public class User { }

@Scope(scopeName="prototype") //manyExample mode public class User { }

3, @ Value is used to inject common type Value

The first way is to break the encapsulation of objects by reflecting the value of filed on attributes.

@Value("xiaohei") private String name;

The second way is to assign a value through the set method without destroying the encapsulation of the object.

@Value("xiaobai") public void setName(String name) { this.name = name; }

4 @ Autowired, @ Resource, @ Qualifier comments

Please refer to the previous blog for details on the assembly method of reference type.

@Autowired private Car car;

@Resource private Car car;

5, @ PostConstruct and @ PreDestroy

@PostConstruct //Call before creating object public void init(){ System.out.println("initial"); } @PreDestroy //Call before object destruction public void destory(){ System.out.println("Destruction"); }

2 December 2019, 02:41 | Views: 1341