Spring学习笔记

Spring学习笔记_IOC

Spring简介

1, 只用IOC

spring.jar , jarkata-commons/commons-loggin.jar

2,IOC容器

实例化具体bean

动态装配

3,AOP支持

安全检查

管理transaction

Spring配置

1,注入类型

　　setter（重要）
构造方法（可以忘记）
　　 接口注入（可以忘记）

<bean id="u" class="com.bjsxt.dao.impl.UserDAOImpl"><!-- new UserDAOImpl()-->
  </bean>
    
  <bean id="userService" class="com.bjsxt.service.UserService">
      <!-- 
      <property name="userDAO" ref="u" />  setter注入 ，调用setxxx方法
       -->
       <constructor-arg>  <!-- 构造方法注入，需要在UserService里面写构造方法，相当于调用了构造方法-->
           <ref bean="u"/>   <!-- 参考了另外一个已经new 的bean-->
       </constructor-arg>
  </bean>

public class UserService {
    
    private UserDAO userDAO;  
    public void add(User user) {
        userDAO.save(user);
    }
    public UserDAO getUserDAO() {
        return userDAO;
    }
    public void setUserDAO(UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    
    public UserService(UserDAO userDAO) {//用于构造方法注入
        super();
        this.userDAO = userDAO;
    }
}

2,id vs. name

　　name可以用特殊字符

<bean name="u" class="com.bjsxt.dao.impl.UserDAOImpl">
  </bean>
    
  <bean id="userService" class="com.bjsxt.service.UserService">
      <!-- 
      <property name="userDAO" ref="u" />
       -->
       <constructor-arg>
           <ref bean="u"/>
       </constructor-arg>
  </bean>

3,简单属性的注入

bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl">
      <property name="daoId" value="8"></property>
      <property name="daoStatus" value="good"></property>
  </bean>

public class UserDAOImpl implements UserDAO {
    private int daoId;
    private String daoStatus;
    
    public int getDaoId() {
        return daoId;
    }

    public void setDaoId(int daoId) {
        this.daoId = daoId;
    }

    public String getDaoStatus() {
        return daoStatus;
    }

    public void setDaoStatus(String daoStatus) {
        this.daoStatus = daoStatus;
    }

    public void save(User user) {
        System.out.println("user saved!");
    }
    
    @Override
    public String toString() {
        return this.daoId + ":" + this.daoStatus;
    }
}

4,bean 中的scope属性

　　singleton:只有一个

　　prototype:每一个都不同

5,集合注入

　　很少用，不重要！

public class UserDAOImpl implements UserDAO {
    /* (non-Javadoc)
     * @see com.bjsxt.dao.UserDAO#save(com.bjsxt.model.User)
     */
    private Set<String> sets;
    private List<String> lists;
    private Map<String , String> maps;
    
    
    public Set<String> getSets() {
        return sets;
    }



    public void setSets(Set<String> sets) {
        this.sets = sets;
    }



    public List<String> getLists() {
        return lists;
    }



    public void setLists(List<String> lists) {
        this.lists = lists;
    }



    public Map<String, String> getMaps() {
        return maps;
    }



    public void setMaps(Map<String, String> maps) {
        this.maps = maps;
    }



    public UserDAOImpl() {
    }
    
    

    public void save(User user) {
        System.out.println("user saved!");
    }
    
    @Override
    public String toString() {
        return "sets size:" + sets.size() + "| lists size:" + lists.size() + "| maps size:" + maps.size() ; 
    }

}

<bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl">
      <property name="sets">
          <set>
              <value>1</value>
              <value>2</value>
          </set>
      </property>
      <property name="lists">
          <list>
              <value>1</value>
              <value>2</value>
              <value>3</value>
          </list>
      </property>
      <property name="maps">
          <map>
              <entry key="1" value="1"></entry>
              <entry key="2" value="2"></entry>
              <entry key="3" value="3"></entry>
              <entry key="4" value="4"></entry>
          </map>
      </property>
  </bean>

  <bean id="userService" class="com.bjsxt.service.UserService">
  <!-- 
      <property name="userDAO">
          <ref bean="userDAO"/>
      </property>
       -->
       <constructor-arg>
           <ref bean="userDAO"/>
       </constructor-arg>
  </bean>

6,自动装配

byName
byType
如果所有的bean都用同一种，可以使用beans的属性：default-autowire

 <bean name="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl">
      <property name="daoId" value="1"></property>
  </bean>
   
  <bean name="userDAO2" class="com.bjsxt.dao.impl.UserDAOImpl">
      <property name="daoId" value="2"></property>
  </bean>
    
  <bean id="userService" class="com.bjsxt.service.UserService" scope="prototype" autowire="byName">
 <!-- 未指定property， 若是byname则自动匹配name等于userDAO的bean,
 若是bytype则匹配类型为userDAO的bean-->

  </bean>

public class UserDAOImpl implements UserDAO {
    
    private int daoId;
    
    public int getDaoId() {
        return daoId;
    }

    public void setDaoId(int daoId) {
        this.daoId = daoId;
    }

    public void save(User user) {
    
        System.out.println("user saved!");
    }
    
    @Override
    public String toString() {
        return "daoId=" + daoId;
    }

}

7,生命周期

lazy-init (不重要) 容器初始化时（ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml")），不初始化，只有用到时才初始化

<bean id="lazy" class="com.foo.ExpensiveToCreateBean" lazy-init="true"/>

init-method destroy-methd 不要和prototype一起用（了解）

<bean id="userService" class="com.bjsxt.service.UserService" init-method="init" destroy-method="destroy" scope="singleton">
      <!-- 
      <property name="userDAO" ref="u" />
       -->
       <constructor-arg>
           <ref bean="u"/>
       </constructor-arg>
  </bean>

public class UserService {
    
    private UserDAO userDAO;  
    
    public void init() {
        System.out.println("init");
    }
    
    public void add(User user) {
        userDAO.save(user);
    }
    public UserDAO getUserDAO() {
        return userDAO;
    }
    public void setUserDAO(UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    
    public UserService(UserDAO userDAO) {
        super();
        this.userDAO = userDAO;
    }
    
    public void destroy() {
        System.out.println("destroy");
    }
}

8,Annotation第一步：

修改xml文件，参考文档<context:annotation-config />

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd">
    <context:annotation-config />
<bean id="u" class="com.bjsxt.dao.impl.UserDAOImpl">
  </bean>
  <bean id="u2" class="com.bjsxt.dao.impl.UserDAOImpl">
  </bean>
    
  <bean id="userService" class="com.bjsxt.service.UserService" >
      
  </bean>
  

</beans>

9,@Autowired(自动装配)

默认按类型by type
如果想用byName，使用@Qulifier
写在private field（第三种注入形式）（不建议，破坏封装）
如果写在set上，@qualifier需要写在参数上

public class UserService {
    
    private UserDAO userDAO;  
    
    public void init() {
        System.out.println("init");
    }

    public void add(User user) {
        userDAO.save(user);
    }
    public UserDAO getUserDAO() {
        return userDAO;
    }
    
    @Autowired
    public void setUserDAO(@Qualifier("u") UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    
    
    public void destroy() {
        System.out.println("destroy");
    }
}

10,@Resource（重要）

加入：j2ee/common-annotations.jar
默认按名称，名称找不到，按类型 @Resource
可以指定特定名称 @Resource(name="u2")
推荐使用
不足：如果没有源码，就无法运用annotation，只能使用xml

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd">
    <context:annotation-config />
  <bean id="userDAO" class="com.bjsxt.dao.impl.UserDAOImpl">
  </bean>
  <bean id="u2" class="com.bjsxt.dao.impl.UserDAOImpl">
  </bean>
    
  <bean id="userService" class="com.bjsxt.service.UserService" >
      
  </bean>
  

</beans>

public class UserService {
    
    private UserDAO userDAO;  
    
    public void init() {
        System.out.println("init");
    }
    
    public void add(User user) {
        userDAO.save(user);
    }
    public UserDAO getUserDAO() {
        return userDAO;
    }
    @Resource(name="u2")
    //@Resource
    public void setUserDAO( UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    

    
    public void destroy() {
        System.out.println("destroy");
    }
}

11,@Component @Service @Controller @Repository 在spring2.5.6中这四个目前没有区别

初始化的名字默认为类名首字母小写
可以指定初始化bean的名字 @Component("u")

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd">
    <context:annotation-config />
    <context:component-scan base-package="com.bjsxt"/>
</beans>

@Component("u") //u=new UserDAO()
public class UserDAOImpl implements UserDAO {

    public void save(User user) {
    
        System.out.println("user saved!");
    }

}

@Component("userService")
public class UserService {
    
    private UserDAO userDAO;  
    
    public void init() {
        System.out.println("init");
    }
    
    public void add(User user) {
        userDAO.save(user);
    }
    public UserDAO getUserDAO() {
        return userDAO;
    }
    
    @Resource(name="u") //把name=u的UserDAO注入
    public void setUserDAO( UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    

    
    public void destroy() {
        System.out.println("destroy");
    }
}

12,@Scope

13,@PostConstruct = init-method; @PreDestroy = destroy-method;

@Scope("singleton")
@Component("userService")
public class UserService {
    
    private UserDAO userDAO;  
    
    @PostConstruct
    public void init() {
        System.out.println("init");
    }
    
    public void add(User user) {
        userDAO.save(user);
    }
    public UserDAO getUserDAO() {
        return userDAO;
    }
    
    @Resource(name="u")
    public void setUserDAO( UserDAO userDAO) {
        this.userDAO = userDAO;
    }
    

    @PreDestroy
    public void destroy() {
        System.out.println("destroy");
    }
}