Spring讲解（三）

依赖注入Bean属性，使用xml配置

1、构造方法注入

案例代码演示

public class User {

    private String username;

    private String password;

    private Integer age;

    public User() {}

    public User(String username, String password, Integer age) {

        this.username = username;

        this.password = password;

        this.age = age;

    }

    public String getUsername() {

        return username;

    }

    public void setUsername(String username) {

        this.username = username;

    }

    public String getPassword() {

        return password;

    }

    public void setPassword(String password) {

        this.password = password;

    }

    public Integer getAge() {

        return age;

    }

    public void setAge(Integer age) {

        this.age = age;

    }

    @Override

    public String toString() {

        return "User{" +

                "username='" + username + '\'' +

                ", password='" + password + '\'' +

                ", age=" + age +

                '}';

    }

}

========================================================================================

通过构造方法注入参数

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<!---->

    <bean id="user" class="com.example.demo.testservice.User">

        <!--相当于调用了有参构造

        	public User(String username, String password, Integer age) {...}

		-->

        <constructor-arg name="username" value="zhangsan"/>

        <constructor-arg name="password" value="123456"/>

        <constructor-arg name="age" value="99"/>

    </bean>

</beans>

========================================================================================

测试函数

public class ServiceTest {

    public static void main(String[] args) {

        ApplicationContext context1 = new ClassPathXmlApplicationContext("beans.xml");

        User user = (User) context1.getBean("user");

        System.out.println(user);

    }

}

执行测试函数得到如下结果：

User{username='zhangsan', password='123456', age=99}

上面的bean.xml还可以通过索引注入参数，其他不变，修改 bean.xml 如下

通过索引注入参数

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.example.demo.testservice.User">

        <!--相当于调用了有参构造

        	public User(String username, String password, Integer age) {...}

		-->

        <constructor-arg index="0" value="李四" type="java.lang.String"/>

        <constructor-arg index="1" value="112233" type="java.lang.String"/>

        <constructor-arg index="2" value="44" type="java.lang.Integer"/>

    </bean>

</beans>

执行测试函数得到如下结果：

User{username='李四', password='112233', age=44}

2、属性setter方法注入（有两种）

上面的 User 和测试函数 ServiceTest 不变，只需要修改 bean.xml即可

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.example.demo.testservice.User">

        <property name="age" value="11"/>

        <property name="password" value="666"/>

        <property name="username" value="王麻子"/>

    </bean>

</beans>

=========================================================================================

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="

http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.example.demo.testservice.User">

        <property name="age">

            <value>11</value>

        </property>

        <property name="password">

            <value>666</value>

        </property>

        <property name="username">

            <value>王麻子</value>

        </property>

    </bean>

</beans>

上面两种配置 bean.xml 都可以，采用第一种配置的比较只管方便。

测试结果都如下：

User{username='王麻子', password='666', age=11}

3、p命名空间注入

上面的 User 和测试函数 ServiceTest 不变，只需要修改 bean.xml即可。

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

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

       xsi:schemaLocation="

        http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="user" class="com.example.demo.testservice.User" p:age="111" p:password="888" p:username="秦始皇" />

</beans>

这种方法不常用，有兴趣的朋友可以对比下 p 命名空间的 bean.xml 和构造方法注入、setter 方法注入的 bean.xml 区别就是加了一个===》xmlns:p ="http://www.springframework.org/schema/p"，就可以使用 p 命名空间了。

运行结果如下：

User{username='秦始皇', password='888', age=111}

4、集合注入

List、Set、Map、Properties

public class Coder {

    private List<String> cars;  // 车

    private Set<String> pats;   // 宠物

    private Map<String,String> information; // 信息

    private Properties mysqlInfo;   // Mysql 连接信息

    public Properties getMysqlInfo() {

        return mysqlInfo;

    }

    public void setMysqlInfo(Properties mysqlInfo) {

        this.mysqlInfo = mysqlInfo;

    }

    public Map<String, String> getInformation() {

        return information;

    }

    public void setInformation(Map<String, String> information) {

        this.information = information;

    }

    public Set<String> getPats() {

        return pats;

    }

    public void setPats(Set<String> pats) {

        this.pats = pats;

    }

    public List<String> getCars() {

        return cars;

    }

    public void setCars(List<String> cars) {

        this.cars = cars;

    }

    @Override

    public String toString() {

        return "Coder{" +

                "cars=" + cars +

                ", pats=" + pats +

                ", information=" + information +

                ", mysqlInfo=" + mysqlInfo +

                '}';

    }

}

=========================================================================================

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://www.springframework.org/schema/beans"

       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

       xsi:schemaLocation="

        http://www.springframework.org/schema/beans

        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="coder" class="com.example.demo.testservice.Coder">

        <!--List 数据注入-->

        <property name="cars">

            <list>

                <value>ofo</value>

                <value>宝马</value>

                <value>奔驰</value>

            </list>

        </property>

        <!--Set数据注入-->

        <property name="pats">

            <set>

                <value>猪</value>

                <value>马</value>

                <value>牛</value>

            </set>

        </property>

        <!--Map 数据注入-->

        <property name="information">

            <map>

                <entry key="name" value="王八蛋"/>

                <entry key="age" value="99"/>

                <entry key="password" value="8888"/>

            </map>

        </property>

        <!--Properties 数据注入-->

        <property name="mysqlInfo">

            <props>

                <prop key="url">mysql:jdbc://localhost:3306/sample</prop>

                <prop key="username">root</prop>

                <prop key="password">root</prop>

            </props>

        </property>

    </bean>

</beans>

=========================================================================================测试函数

public class ServiceTest {

    public static void main(String[] args) {

        ApplicationContext context1 = new ClassPathXmlApplicationContext("beans.xml");

        Coder coder = (Coder) context1.getBean("coder");

        System.out.println("车："+coder.getCars());

        System.out.println("宠物："+coder.getPats());

        System.out.println("个人信息："+coder.getInformation());

        System.out.println("数据库信息信息："+coder.getMysqlInfo());

    }

}

运行结果如下:

车：[ofo, 宝马, 奔驰]

宠物：[猪, 马, 牛]

个人信息：{name=王八蛋, age=99, password=8888}

数据库信息信息：{password=root, url=mysql:jdbc://localhost:3306/sample, username=root}

巴特西

Spring讲解（三）

依赖注入Bean属性，使用xml配置

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