[Java知识库]SpringStudy

SpringStudy01-HelloSpring

这里本人使用的是maven，所以必须导入maven依赖
下面图是该例子包的结构

创建一个HelloSpring类

public class Hello {
    private String str;

    public String getStr() {
        return str;
    }

    public void setStr(String str) {
        this.str = str;
    }

    @Override
    public String toString() {
        return "Hello{" +
                "str='" + str + '\'' +
                '}';
    }
}

编写beans.xml文件

<?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就是java对象 , 由Spring创建和管理,id随便取，class是指注册的类的路径-->
    <bean id="hello" class="com.wang.pojo.Hello">
    <!-- property是给类中的属性赋值用的，name必须与所赋值属性的名字一样，value是指所赋的值-->
        <property name="str" value="Spring"/>
    </bean>

</beans>

编写测试类

public class MyTest {

    public static void main(String[] args){
//
      //获取spring上下文对象
        ApplicationContext context=new ClassPathXmlApplicationContext("beans.xml");
        Hello hello=(Hello)context.getBean("hello");//获取bean对象
        System.out.println(hello.toString());//输出
    }

}

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SpringStudy02-ioc01(引用ref)

包的结构

dao层

• UserDao接口

public interface UserDao {
    void getuser();
}

• UserDaoImpl类

public class UserDaoImpl implements UserDao {
    public void getuser() {
        System.out.println("该我表演了！");
    }
}

• UserDaoMysqlImpl类

  public void getuser() {
        System.out.println("改你表演了！");
    }
}

service层

• UserService接口

public interface UserService {
    void getuser();
}

• UserServiceImpl类

public class UserServiceImpl implements UserService{
    private UserDao userdao;

    public void setUserdao(UserDao userdao) {
        this.userdao = userdao;
    }

    public void getuser() {
        userdao.getuser();
    }
}

beans.xml文件

<?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就是java对象 , 由Spring创建和管理-->
    <bean id="DaoIml" class="com.wang.dao.UserDaoImpl"/>
    <bean id="MysqlIml" class="com.wang.dao.UserDaoMysqlImpl"/>
    
    <bean id="ServiceIml" class="com.wang.service.UserServiceImpl">
    <!-- 将DaoIml赋值给ServiceIml中的userdao-->
        <property name="userdao" ref="DaoIml"></property>
    </bean>
<!--    ref:引用spring容器中创建好的对象-->
<!--    value:值，   基本的数据类型-->
    <bean id="ServiceIml02" class="com.wang.service.UserServiceImpl">
        <property name="userdao" ref="MysqlIml"></property>
    </bean>
</beans>

测试类

public class MyTest {

    public static void main(String[] args){

//测试是否赋值成功
        ApplicationContext context=new ClassPathXmlApplicationContext("beans.xml");
        UserServiceImpl userService=(UserServiceImpl)context.getBean("ServiceIml02");
        userService.getuser();


        UserService userService1=new UserServiceImpl();
        ((UserServiceImpl)userService1).setUserdao(new UserDaoImpl());
        userService1.getuser();
    }

}

注意点
UserServiceImpl类中的userdao类型是UserDao接口，否则类型不一致会导致赋值失败

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SpringStudy03-构造器注入(有参构造)

• 编写User1类

public class User1 {
    private String name1;
    private int age;
    private String sex;

    public User1() {
    }//无参构造

    public User1(String name1, int age, String sex) {
        this.name1 = name1;
        this.age = age;
        this.sex = sex;
    }//此处就是有参构造，本例就是通过有参构造进行赋值

    public String getName1() {
        return name1;
    }

    public void setName1(String name1) {
        this.name1 = name1;
    }

    public int getAge() {
        return age;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    @Override
    public String toString() {
        return "User1{" +
                "name1='" + name1 + '\'' +
                ", age=" + age +
                ", sex='" + sex + '\'' +
                '}';
    }
}

• 在beans.xml注册bean
  1.通过属性类型赋值

<bean id="user1" class="com.wang.pojo.User1">
    <constructor-arg type="java.lang.String" value="wdawd"></constructor-arg>
    <constructor-arg type="int" value="34"></constructor-arg>
    <constructor-arg type="java.lang.String" value="男"></constructor-arg>
</bean>

2. 通过下标进行赋值（从0开始）

<bean id="user1" class="com.wang.pojo.User1">
        <constructor-arg index="0" value="wdwda"></constructor-arg>
        <constructor-arg index="1" value="34"></constructor-arg>
        <constructor-arg index="2" value="nan"></constructor-arg>
    </bean>

3. 通过参数名赋值

 <bean id="user1" class="com.wang.pojo.User1">
        <constructor-arg name="name1" value="adawd"></constructor-arg>
        <constructor-arg name="age" value="34"></constructor-arg>
        <constructor-arg name="sex" value="nan"></constructor-arg>
    </bean>

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

SpringStudy04-di注入

首先创建一个Student类，该类中包含各种属性，让我们看看各种属性注入的方法

public class Student {
//属性
    private String name;
    private Address address;
    private String[] books;
    private List<String> hobbys;
    private Map<String,String> card;
    private Set<String> games;
    private String wife;
    private Properties info;




    public String getName() {
        return name;
    }

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

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }

    public String[] getBooks() {
        return books;
    }

    public void setBooks(String[] books) {
        this.books = books;
    }

    public List<String> getHobbys() {
        return hobbys;
    }

    public void setHobbys(List<String> hobbys) {
        this.hobbys = hobbys;
    }

    public Map<String, String> getCard() {
        return card;
    }

    public void setCard(Map<String, String> card) {
        this.card = card;
    }

    public Set<String> getGames() {
        return games;
    }

    public void setGames(Set<String> games) {
        this.games = games;
    }

    public String getWife() {
        return wife;
    }

    public void setWife(String wife) {
        this.wife = wife;
    }

    public Properties getInfo() {
        return info;
    }

    public void setInfo(Properties info) {
        this.info = info;
    }


    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", address=" + address.toString() +
                ", books=" + Arrays.toString(books) +
                ", hobbys=" + hobbys +
                ", card=" + card +
                ", games=" + games +
                ", wife='" + wife + '\'' +
                ", info=" + info +
                '}';
    }
}

其中的Address类

public class Address {
    private String address;

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    @Override
    public String toString() {
        return "Address{" +
                "address='" + address + '\'' +
                '}';
    }
}

下面进行bean注册

• 首先将Adress类注册

<bean id="address" class="com.wang.pojo.Address">
    </bean>

• 注册Student类

<bean id="student" class="com.wang.pojo.Student">
        <!--    第一种：普通值注入 value-->
        <property name="name" value="we"></property>
        <!--  第二种：bean注入 ref引用      -->
        <property name="address" ref="address"></property>
        <!--   数组注入     -->
        <property name="books">
           <array>
               <value>红楼梦</value>
               <value>西游记</value>
               <value>三国演义</value>
               <value>水浒传</value>
           </array>
        </property>
        <!--   List注入     -->
        <property name="hobbys">
            <list>
                <value>打游戏</value>
                <value>学习</value>
                <value>看书</value>
            </list>
        </property>
        <!--  Map注入      -->
        <property name="card">
            <map>
                <entry key="身份证" value="4141414141414141414"></entry>
                <entry key="学号" value="20210903"></entry>
            </map>
        </property>
        <!--  Set注入      -->
        <property name="games">
            <set>
                <value>王者荣耀</value>
                <value>和平精英</value>
            </set>
        </property>
        <!--  null值注入 如果为空值注入则value为空      -->
        <property name="wife">
            <null></null>
        </property>
        <!--  properties值注入      -->
        <property name="info">
            <props>
                <prop key="学号">20210903</prop>
                <prop key="性别">男</prop>
                <prop key="姓名">we</prop>
            </props>
        </property>
    </bean>

注意map注入！！！！！！！！

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SpringStudy05-p命名注入和c命名注入

首先编写User类

public class User {
    private String name;
    private String age;

    public User() {
    }

    public User(String name, String age) {
        this.name = name;
        this.age = 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 "User{" +
                "name='" + name + '\'' +
                ", age='" + age + '\'' +
                '}';
    }
}

进行p和c命名注入需要在xml文件中beans标签加入
xmlns:p=“http://www.springframework.org/schema/p”
xmlns:c="http://www.springframework.org/schema/c"
如下所示

<?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"
       xmlns:c="http://www.springframework.org/schema/c"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans.xsd">
                       
    <!--  p命名注入   必须引入xmlns:p="http://www.springframework.org/schema/p -->
    <bean id="user" class="com.wang.pojo.User" p:age="20" p:name="we">
    </bean>
    <!--  c命名注入 必须引用 xmlns:c="http://www.springframework.org/schema/c
    c命名注入实际运用构造器注入:constructor-arg
    -->
    <bean id="user2" class="com.wang.pojo.User" c:name="20" c:age="we1"></bean>

</beans>

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

SpringStudy06-自动装配(Autowired)

创建Cat4，Dog4，People这三个类

• Cat4.java

public class Cat4 {
    public void shout(){
        System.out.println("喵~");
    }
}

• Dog4.java

public class Dog4 {
    public void shout(){
        System.out.println("汪~");
    }
}

• People4.java

public class People4 {
    private Dog4 dog4;
    private Cat4 cat4;
    private String name;

    public Dog4 getDog4() {
        return dog4;
    }

    public void setDog4(Dog4 dog4) {
        this.dog4 = dog4;
    }

    public Cat4 getCat4() {
        return cat4;
    }

    public void setCat4(Cat4 cat4) {
        this.cat4 = cat4;
    }

    public String getName() {
        return name;
    }

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

    @Override
    public String toString() {
        return "People4{" +
                "dog4=" + dog4 +
                ", cat4=" + cat4 +
                ", name='" + name + '\'' +
                '}';
    }
}

• beans.xml文件

<?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.xsd">


    <bean id="cat4" class="com.wang.pojo4.Cat4"></bean>
    <bean id="dog4" class="com.wang.pojo4.Dog4"></bean>

    <!--  使用byName自动装配
    byName:会自动在容器上下文中查找和自己对象set方法后面的值所对应的bean id!
    即本例中People4类中的set方法参数名的匹配 => 例：setCat4(Cat4 cat4)中的cat与bean中id的匹配
    如果<bean id="cat4" class="com.wang.pojo.Cat4"></bean>改为<bean id="cat22" class="com.wang.pojo.Cat4"></bean>
    则会出现异常 即名字不重复就不会报错
    -->
  <bean id="people4" class="com.wang.pojo.People4" autowire="byName">
               <property name="name" value="we"></property>
          </bean>



    <!--  使用byType自动装配
    byType:会自动在容器上下文中查找和自己对象属性类型相同的beanid!
    如果<bean id="cat4" class="com.wang.pojo.Cat4"></bean>改为<bean id="cat22" class="com.wang.pojo.Cat4"></bean>
    则不会出现异常
    但是属性类型必须唯一，否则会报错 =>上例增加一个<bean id="cat11" class="com.wang.pojo.Cat4"></bean>，就会报错(多了一个类型相同的)
    使用byType自动装配可以不用命名id 即<bean class="com.wang.pojo.Cat4"></bean>
    -->
    <bean id="people4" class="com.wang.pojo.People4" autowire="byType">
        <property name="name" value="we"></property>
    </bean>


</beans>

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

SpringStudy07-使用注解进行自动装配(@Autowired @Resource)

@Autowire通过byType方式实现
@Resource默认通过byname方式实现，如果找不到则通过byType，都找不到就报错

1. @Autowire

• 首先xml文件有变化

<?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.xsd">

<!--  @Autowired  通过bytype方式自动装配-->
                              <!-- 使用注解@Autowired自动装配  -->
<!--    开启注解支持     这一步必须有-->
    <context:annotation-config></context:annotation-config>


    <bean id="dog2" class="com.wang.pojo2.Dog2"></bean>
    <bean id="=cat2" class="com.wang.pojo2.Cat2"></bean>
    <bean id="dog22" class="com.wang.pojo2.Dog2"></bean>
    <bean id="cat22" class="com.wang.pojo2.Cat2"></bean>
    <bean id="people2" class="com.wang.pojo2.People2">
        <property name="name2" value="we2"></property>
    </bean>
<!-- 使用注解@Autowired自动装配可以将People2中的set方法去掉,也可以运行成功-->
<!--如果增加<bean id="dog22" class="com.wang.pojo2.Dog2"></bean>
          <bean id="=cat22" class="com.wang.pojo2.Cat2"></bean>
    可以使用@Qualifier(value="dog22")进行特定自动装配


    @Autowired  //注释自动装配
    @Qualifier(value = "dog22")
    private Dog2 dog2;
    @Autowired  //注释自动装配
    @Qualifier(value = "cat22")//指定特定的
    private Cat2 cat2;
    -->


<!--    注解自动装配@Resource 它本身先进行id查找 有相同则正常运行 否则报错
                                      其次可以进行类型查找 相同则运行
                                      由此可看出即使查找id不相同 类型相同的话也可以进行自动装配
        <bean id="dog2231" class="com.wang.pojo2.Dog2"></bean>
        <bean id="=cat21314" class="com.wang.pojo2.Cat2"></bean>
        自行进行测试
        @Resource(name="")也可以指定特定的id

        @Resource相比前两种更加高级
        在beans3.xml进行测试
-->
</beans>

• Cat2类

public class Cat2 {
    public void shout(){
        System.out.println("喵~");
    }
}

• Dog2类

public class Dog2 {
    public void shout(){
        System.out.println("汪~");
    }
}

• People2类

public class People2 {
    @Autowired  //注释自动装配
    @Qualifier(value = "dog22")//指定特定的bean对象进行自动装配
    private Dog2 dog2;
    @Autowired  //注释自动装配
    @Qualifier(value = "cat22")//指定特定的
    private Cat2 cat2;
    private String name2;


    public Dog2 getDog2() {
        return dog2;
    }

//    public void setDog2(Dog2 dog2) {
//        this.dog2 = dog2;
//    }

    public Cat2 getCat2() {
        return cat2;
    }

//    public void setCat2(Cat2 cat2) {
//        this.cat2 = cat2;
//    }

    public String getName2() {
        return name2;
    }

    public void setName2(String name2) {
        this.name2 = name2;
    }


    @Override
    public String toString() {
        return "People2{" +
                "dog2=" + dog2 +
                ", cat2=" + cat2 +
                ", name2='" + name2 + '\'' +
                '}';
    }
}

2.@Resource

• xml文件

<?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.xsd">
<!--    @Resource 自动装配    默认通过byname方式实现，如果找不到则通过byType，都找不到就报错-->
    <context:annotation-config></context:annotation-config>

    <bean id="dog3" class="com.wang.pojo3.Dog3"></bean>
    <bean id="cat3" class="com.wang.pojo3.Cat3"></bean>
    <bean id="people3" class="com.wang.pojo3.People3"></bean>
</beans>

重点是People3类

public class People3 {
    @Resource//注解自动装配
    private Dog3 dog3;
    @Resource
    private Cat3 cat3;
    private String name3;

    public Dog3 getDog3() {
        return dog3;
    }

    public void setDog3(Dog3 dog3) {
        this.dog3 = dog3;
    }

    public Cat3 getCat3() {
        return cat3;
    }

    public void setCat3(Cat3 cat3) {
        this.cat3 = cat3;
    }

    public String getName3() {
        return name3;
    }

    public void setName3(String name3) {
        this.name3 = name3;
    }


    @Override
    public String toString() {
        return "People3{" +
                "dog3=" + dog3 +
                ", cat3=" + cat3 +
                ", name3='" + name3 + '\'' +
                '}';
    }
}

注意：@Resource(name="")进行特定指定bean对象

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