从零学Spring -- Spring属性注入

左手的ㄟ右手 2022-05-13 15:00 126阅读 0赞

### 文章目录 ###

*   *   *  1.对于类成员，注入方式三种
         *  2.Spring 支持
         *  当属性中有对象属性注入方式跟上方有一点区别
         *  p名称空间属性注入
         *   *  1.p名称空间属性注入优点
             *  ２．使用格式
         *  SqEL 注入
         *  复杂类型注入

### 1.对于类成员，注入方式三种 ###

*  构造函数注入
 *  属性setting 注入
 *  接口注入

### 2.Spring 支持 ###

*  构造函数注入  
    1.创建实体类

package com.imooc.Demo4;
    
    import org.junit.Test;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class SpringDemo1 { 
        @Test
        public  void  test(){ 
            ApplicationContext applicationContext=new ClassPathXmlApplicationContext("Springconfig.xml");
            Users user = (Users) applicationContext.getBean("User");
            System.out.println(user);
        }
    }

２.Spring xml配置

３．创建测试

４．输出信息

信息: Loading XML bean definitions from class path resource [Springconfig.xml]
    Users{name='gyc', age='13'}
    
    Process finished with exit code 0

*  属性setting 注入  
    1.创建实体类并将属性封装getset方法

package com.imooc.Demo4;
    
    public class Users { 
        private String name;
        private String age;
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public String getAge() { 
            return age;
        }
    
    
        public void setAge(String age) { 
            this.age = age;
        }
    /* public Users(String name, String age) { this.name = name; this.age = age; } */
    
    
        @Override
        public String toString() { 
            return "Users{" +
                    "name='" + name + '\'' +
                    ", age='" + age + '\'' +
                    '}';
        }
    }

２.配置Springxml 方法

３．进行测试

４．输出信息

Users{name='gyc', age='13'}

### 当属性中有对象属性注入方式跟上方有一点区别 ###

１．实体类

package com.imooc.Demo4;
    
    public class Users { 
        private String name;
        private String age;
      
    //对象属性
      private  cat cat;
    
        public com.imooc.Demo4.cat getCat() { 
            return cat;
        }
    
        public void setCat(com.imooc.Demo4.cat cat) { 
            this.cat = cat;
        }
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public String getAge() { 
            return age;
        }
    
    
        public void setAge(String age) { 
            this.age = age;
        }
    /* public Users(String name, String age) { this.name = name; this.age = age; } */
    
    
        @Override
        public String toString() { 
            return "Users{" +
                    "name='" + name + '\'' +
                    ", age='" + age + '\'' +
                    ", cat=" + cat +
                    '}';
        }
    }

cat 类

package com.imooc.Demo4;
    
    public class cat { 
        private  String name;
        private  String age;
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public String getAge() { 
            return age;
        }
    
        public void setAge(String age) { 
            this.age = age;
        }
    
        @Override
        public String toString() { 
            return "cat{" +
                    "name='" + name + '\'' +
                    ", age='" + age + '\'' +
                    '}';
        }
    }

2.SpringXml 注入方式

<bean id="cat" class="com.imooc.Demo4.cat">
            <property name="age" value="3岁"></property>
            <property name="name" value="小黑"></property>
        </bean>
        
        <bean id="User" class="com.imooc.Demo4.Users">
    
            <property name="age" value="13"></property>
            <property name="name" value="gyc"></property>
            
            <property name="cat" ref="cat"></property>
        </bean>
    </beans>

3.输出信息

Users{name='gyc', age='13', cat=cat{name='小黑', age='3岁'}}

### p名称空间属性注入 ###

#### 1.p名称空间属性注入优点 ####

*  为了导入p名称空间
 *  为了简化xml的配置

#### ２．使用格式 ####

*  p:<属性名>=“xxxx”;
 *  p:<属性名> -ref=“xxx”; 引用其他Ｂean对象  
    　还是以上面的例子为例　  
    １．引入ｐ名称空间

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

2.配置xml

### SqEL 注入 ###

SqEL:Spring expeession language 　spring 表达语言

*  语法：\#\{表达式\}
 *

SpEl 表达式语句：　  
＃\{‘hello’\}:使用字符串  
\#\{beanid\}:使用另一个bean  
\#\{beanid.属性\}　使用指定属性  
＃\{beanid.方法\}　使用指定方法　  
还是以上面的为例子,spring XML配置如下：

### 复杂类型注入 ###

１．创建实体类

package com.imooc.demo5;
    
    import java.util.*;
    
    /*复杂属性注入*/
    public class a { 
        private  String[] srt;
        private List list;
        private Map map;
        private Set set;
        private Properties properties;
    
        public String[] getSrt() { 
            return srt;
        }
    
        public void setSrt(String[] srt) { 
            this.srt = srt;
        }
    
        public List getList() { 
            return list;
        }
    
        public void setList(List list) { 
            this.list = list;
        }
    
        public Map getMap() { 
            return map;
        }
    
        public void setMap(Map map) { 
            this.map = map;
        }
    
        public Set getSet() { 
            return set;
        }
    
        public void setSet(Set set) { 
            this.set = set;
        }
    
        public Properties getProperties() { 
            return properties;
        }
    
        public void setProperties(Properties properties) { 
            this.properties = properties;
        }
    
        @Override
        public String toString() { 
            return "a{" +
                    "srt=" + Arrays.toString(srt) +
                    ", list=" + list +
                    ", map=" + map +
                    ", set=" + set +
                    ", properties=" + properties +
                    '}';
        }
    }

2.配置Springxml 将属性注入

<bean id="a" class="com.imooc.demo5.a">
        <property name="list">
            <list>
                <value>a</value>
                <value>b</value>
                <value>c</value>
            </list>
    
        </property>
        
        <property name="srt">
            <list>
                <value>a</value>
                <value>b</value>
                <value>c</value>
            </list>
    
        </property>
        
        <property name="set">
            <set>
                <value>a</value>
                <value>b</value>
            </set>
    
        </property>
        
        <property name="map">
            <map>
                <entry key="a" value="b"></entry>
    
            </map>
    
        </property>
        <property name="properties">
            <props>
                <prop key="user">root</prop>
                <prop key="password">password</prop>
            </props>
    
        </property>
    </bean>

3.创建测试类

package com.imooc.demo5;
    
    import org.junit.Test;
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    public class test { 
        @Test
        public void  test(){ 
            ApplicationContext applicationContext=new ClassPathXmlApplicationContext("Springconfig.xml");
            a a = (a) applicationContext.getBean("a");
            System.out.println(a);
        }
    }

4.输出日志

a{srt=[a, b, c], list=[a, b, c], map={a=b}, set=[a, b], properties={user=root, password=password}}