Spring通过注解装配Bean

通过注解实现ServiceImpl业务

一、使用@Component装配Bean

1、 定义类：User

在类上面加@Component注解，在属性上面加@Value值

package com.wbg.springxmlbean.entity;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component(value = "user")
public class User {
    @Value("2")
    private int id;
    @Value("韦邦杠")
    private String name;
    @Value("18")
    private int age;
    private Role role;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", role=" + role +
                ", name='" + name + '\'' +
                ", age=" + age +
                '}';
    }

    public Role getRole() {
        return role;
    }

    public void setRole(Role role) {
        this.role = role;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

}

2、使用@ComponentScan注解进行扫描包的路径

创建一个类，类上面加@CompontScan注解

测试：

 ApplicationContext context=new AnnotationConfigApplicationContext(PojoConfig.class);
      User user=context.getBean(User.class);
        System.out.println(user);

3、创建UserService接口

public interface UserService {
    User getUser();
    void setUser(User user);
}

4、创建实现类UserServiceImpl，在该类上面使用@Component注解

package com.wbg.springxmlbean.service.impl;

import com.wbg.springxmlbean.entity.User;
import com.wbg.springxmlbean.service.UserService;
import org.springframework.stereotype.Component;

/**
 * 这里的@Component 表名它是一个Spring所需要的 Bean
 * 而且也实现了对于的UserService接口所定义的方法getUser、setUser
 */
@Component
public class UserServiceImpl implements UserService {

    private User user;
    @Override
    public User getUser() {
        return user;
    }
    @Override
    public void setUser(User user){
        System.out.println("进入了UserServiceImpl.setUser");
        System.out.println(user);
    }
}

5、配置@ComponentScan制定包扫描

创建一个ApplicationConfig类，该类上面使用@ComponentScan注解

package com.wbg.springxmlbean.service.impl;

import com.wbg.springxmlbean.entity.User;
import org.springframework.context.annotation.ComponentScan;

/**
 * basePackageClasses直接扫描指定类
 */
@ComponentScan(basePackageClasses = {User.class,UserServiceImpl.class})
/**
 * basePackages可读性好，但不建议使用，因为修改包名没有提示
 */
//@ComponentScan(basePackages = {"com.wbg.springxmlbean.entity","com.wbg.springxmlbean.service"})

public class ApplicationConfig {
}

测试：

 ApplicationContext context=new AnnotationConfigApplicationContext(ApplicationConfig.class);
      User user=context.getBean(User.class);
      UserService userService=context.getBean(UserService.class);
      userService.setUser(user)

二、自动装配-@Autowired

eneity的Role类：

package com.wbg.springxmlbean.entity;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Role {
    @Value("1")
    private int id;
    @Value("roleName_1")
    private String roleName;
    @Value("note_1")
    private String note;

    @Override
    public String toString() {
        return "Role{" +
                "id=" + id +
                ", roleName='" + roleName + '\'' +
                ", note='" + note + '\'' +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getRoleName() {
        return roleName;
    }

    public void setRoleName(String roleName) {
        this.roleName = roleName;
    }

    public String getNote() {
        return note;
    }

    public void setNote(String note) {
        this.note = note;
    }
}

service创建接口：RoleService

package com.wbg.springxmlbean.service;

public interface RoleService {
    void printRoleInfo();
}

impl实现类：RoleServiceImpl

@Component
public class RoleServiceImpl implements RoleService {

    @Autowired
    private Role role;
    @Override
    public void printRoleInfo() {
        System.out.println(role);
    }
}

创建xml扫描:

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-4.3.xsd">
    <!--指定要扫描的包，如果有多个可以用逗号隔开-->
    <context:component-scan base-package="com.wbg.springxmlbean.service,com.wbg.springxmlbean.entity"/>
</beans>

测试：

 ApplicationContext context=new ClassPathXmlApplicationContext("Role12.xml");
        RoleService userService=context.getBean(RoleService.class);
        userService.printRoleInfo();

当有注解的时候

当没有的时候

三、注解@Primary

上面类：RoleServiceImpl实现了RoleService接口

再创建一个类RoleServiceImpl2进行实现RoleService接口

则RoleService接口就有两个实现类，但Spring ioc不知道采用哪个注入，然后就会出错

@Component
public class RoleServiceImpl2 implements RoleService {

    @Autowired
    private Role role;

    @Override
    public void printRoleInfo() {
        System.out.println("进入了RoleServiceImpl22");
        System.out.println(role);
    }
}

在启动的时候报错

org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.wbg.springxmlbean.service.RoleService' available: expected single matching bean but found 2: roleServiceImpl,roleServiceImpl2

通过@Primary注解告诉Sring ioc

测试：

1、RoleServiceImpl2

去掉RoleServiceImpl2上面的@primary注解

测试RoleServiceImpl

四、注解@Qualifier

把上面的@Primary注解去掉，然后在Controller进行使用

现在接口AdminService有两个实现类

AdminServiceImpl

AdminServiceImpl2

然后在Controller进行实现

五、使用@Bean装配Bean

@Bean的配置项中包含4个配置

name:是一个字符中数组，允许多个

autowire:标识是否是一个引用Bean对象，默认值：Autowire.NO

initMethd:自定义初始化方法

destroyMethod:自定义销毁方法

代码：

package com.wbg.springxmlbean.spring;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.sql.DataSource;
import java.beans.PropertyVetoException;
@Configuration
public class ConfigDataSource {
    @Bean(name = "dataSource")
    public DataSource getDataSource() throws PropertyVetoException {
        ComboPooledDataSource dataSource=new ComboPooledDataSource();
        dataSource.setDriverClass("org.mariadb.jdbc.Driver");
        dataSource.setJdbcUrl("jdbc:mariadb://localhost:3306/wbg_logistics");
        dataSource.setUser("root");
        dataSource.setPassword("123456");
        dataSource.setMaxPoolSize(30);
        return dataSource;
    }
}

实现：

接口：

public interface RoleDataSourceService {
    Role getRole(int id);
}

实现接口

package com.wbg.springxmlbean.service.impl;

import com.wbg.springxmlbean.entity.Role;
import com.wbg.springxmlbean.service.RoleDataSourceService;
import com.wbg.springxmlbean.spring.ConfigDataSource;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

@Component
public class RoleDataSourceServiceImpl implements RoleDataSourceService {

    @Autowired
    ConfigDataSource dataSource=null;

    @Override
    public Role getRole(int id) {
        Connection con=null;
        ResultSet rs=null;
        PreparedStatement ps=null;
        Role role=null;
        try {
            con=dataSource.getDataSource().getConnection();
            ps=con.prepareStatement("select * from role where id = ?");
            ps.setInt(1,id);
            rs=ps.executeQuery();
            while (rs.next()){
                role=new Role();
                role.setId(rs.getInt(1));
                role.setNote(rs.getString(2));
                role.setNote(rs.getString(3));
            }
        } catch (PropertyVetoException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return role;
    }

}

这里Role12.xml需要扫描:

测试：

 ApplicationContext context=new ClassPathXmlApplicationContext("Role12.xml");
        RoleDataSourceService roleDataSourceService=context.getBean(RoleDataSourceService.class);
        System.out.println(roleDataSourceService.getRole(1));

六、装配的混合使用

创建一个配置类：

@ComponentScan(basePackages = "com.wbg.springxmlbean.service")
@ImportResource({"classpath:spring-dataSource.xml"})
public class ApplicationConfig {
}

创建xml文件：

spring-dataSource.xml

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
       ">
    <!--创建数据源-->
    <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
        <property name="driverClass" value="org.mariadb.jdbc.Driver" />
        <property name="jdbcUrl" value="jdbc:mariadb://localhost:3306/wbg_logistics" />
        <property name="user" value="root" />
        <property name="password" value="123456" />

        <property name="maxPoolSize" value="30" />
        <property name="minPoolSize" value="10" />
        <property name="autoCommitOnClose" value="false" />
        <property name="checkoutTimeout" value="10000" />
        <property name="acquireRetryAttempts" value="2" />
    </bean>

</beans>

创建接口：RoleDataSourceService2

创建实现类：

使用注解@Autowired

package com.wbg.springxmlbean.service;

import com.wbg.springxmlbean.entity.Role;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.sql.DataSource;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

@Service
public class RoleDataSourceService2Impl implements RoleDataSourceService2 {

    @Autowired
    DataSource dataSource;
    @Override
    public Role getRole(int id) {
        Connection con=null;
        ResultSet rs=null;
        PreparedStatement ps=null;
        Role role=null;
        try {
            con= dataSource.getConnection();
            ps=con.prepareStatement("select * from role where id = ?");
            ps.setInt(1,id);
            rs=ps.executeQuery();
            while (rs.next()){
                role=new Role();
                role.setId(rs.getInt(1));
                role.setRoleName(rs.getString(2));
                role.setNote(rs.getString(3));
            }
        }  catch (SQLException e) {
            e.printStackTrace();
        }
        return role;
    }
}

测试：

ApplicationContext context=new AnnotationConfigApplicationContext(ApplicationConfig.class);
        RoleDataSourceService2 roleDataSourceService=context.getBean(RoleDataSourceService2.class);
        System.out.println(roleDataSourceService.getRole(2));

demo:https://github.com/weibanggang/springAnnotation.git