Spring的基本使用方法

最开始的基础:

Dao层如下:

package com.zzx.dao;
public interface UserDao {
    void adds();
}

Dao实现类:

package com.zzx.dao.impl;
import com.zzx.dao.UserDao;
public class UserDaoImpl implements UserDao {
    @Override
    public void adds() {
        System.out.println("Spring学习的第一天.对于Dao层的调用");
    }
}

Service层:

package com.zzx.service;
public interface UserService {
    void add();
}

Service实现类:

package com.zzx.service.impl;
import com.zzx.service.UserService;
public class UserServiceImpl implements UserService{
    @Override
    public void add() {
        System.out.println("这是Spring第一天对于UserService的调用");
    }
}

配置application.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"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

    <!-- IOC 控制符反转,将创建对象的动作交给Spring容器 -->
    <!-- 配置文件就是spring的容器 -->
    <!-- 在此处配置需要由Spring创建对象的类
        id 创建后的对象名,后续需要使用该id从容器获得对象
        class 要创建对象的类路径
    -->
    <bean id="userService" class="com.zzx.service.impl.UserServiceImpl"></bean>
    <bean id="userDao" class="com.zzx.dao.impl.UserDaoImpl"></bean>


</beans>

最后写一个实现类,来测试代码是否正确:

package com.zzx.test;

import com.zzx.dao.UserDao;
import com.zzx.model.User;
import com.zzx.service.DiService;
import com.zzx.service.UserService;
import org.junit.Test;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserTest {
    @Test
    public void 从容器获得对象(){
        //1.获得对象
        String path = "application.xml";        //此处的路径以src为根
        ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext(path);

        //2.从容器获得对象,参数是xml中的id
        UserService userService =(UserService) app.getBean("userService");

        //3.使用对象
        userService.add();
    }
}

但是我们在日常开发中,不会这么写,那么就再次加大一个难度点:
dao层:

package com.zzx.dao;

public interface DI {
    void add();
}

dao的实现类:

package com.zzx.dao.impl;


import com.zzx.dao.DI;

public class DiDaoImpl implements DI {
    @Override
    public void add() {
        System.out.println("Spring第一天,注入实现");
    }
}

Service层:

package com.zzx.service;

public interface DiService {
    void add();
}

Service的实现类:

package com.zzx.service.impl;

import com.zzx.dao.DI;
import com.zzx.service.DiService;

public class DiServiceImpl implements DiService {
     private DI di;

    //提供属性的set方法
    public void setDi(DI di) {
        this.di = di;
    }

    @Override
    public void add() {
        System.out.println("暗黑三等奖爱啥啥");
        di.add();
    }
}

xml配置如下:

<?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">

    <!-- IOC 控制符反转,将创建对象的动作交给Spring容器 -->
    <!-- 配置文件就是spring的容器 -->
    <!-- 在此处配置需要由Spring创建对象的类
        id 创建后的对象名,后续需要使用该id从容器获得对象
        class 要创建对象的类路径
    -->
    <bean id="diService" class="com.zzx.service.impl.DiServiceImpl">
        <property name="di" ref="diDao"></property>
    </bean>

    <bean id="diDao" class="com.zzx.dao.impl.DiDaoImpl"></bean>


</beans>

测试类如下:

  @Test
    public void Di注入(){
        //1.获得对象
        String path = "application1.xml";
        ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext(path);

        //2.从容器获得对象,参数是xml中的id
        DiService diService = (DiService) app.getBean("diService");
        System.out.println(diService);
        //3.使用对象
        diService.add();
    }

如果我们想给各种类型的属性赋值(model代码如下):

package com.zzx.model;

public class User {
    private int id;
    private Integer age;
    private String name;

    public User(int id) {
        this.id = id;
    }

    public User(Integer age) {
        this.age = age;
    }

    public User(String name) {
        this.name = name;
    }

    public User(int id, Integer age) {
        this.id = id;
        this.age = age;
    }

    public User(int id, String name) {
        this.id = id;
        this.name = name;
    }

    public User(Integer age, String name) {
        this.age = age;
        this.name = name;
    }

    public User(int id, Integer age, String name) {
        this.id = id;
        this.age = age;
        this.name = name;
    }

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

xml赋值写法如下:

<?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">

    <!--<property> 标签专用于 set方法注入-->
    <!--<constructor-arg>标签专用于 构造方法注入
        type : 构造方法中参数的类型
        index : 构造方法中参数的下标 , 从0开始
        name : 构造方法中参数的变量名
        value : 参数值 - 基本类型 - 特殊的,给String赋值使用value
        ref  : 参数值  - 引用类型
     ps: 当类中属性类型是int等基本类型时,type直接写基本类型
         当类中属性类型是包装类类型时,type需要写包装类全路径
    -->
    <bean id="user" class="com.zzx.model.User">
        <constructor-arg type="int" index="0" value="18"></constructor-arg>
        <constructor-arg type="java.lang.Integer" index="1" value="28"></constructor-arg>
        <constructor-arg index="2" name="name" value="张三"></constructor-arg>
    </bean>

    <bean id="users" class="com.zzx.model.User">
        <constructor-arg index="0" name="id" value="18" ></constructor-arg>
        <constructor-arg index="1" name="age" value="28"></constructor-arg>
        <constructor-arg index="2" name="name" value="李四"></constructor-arg>
    </bean>

    <bean id="user1" class="com.zzx.model.User">
        <constructor-arg index="0" name="age" value="89"></constructor-arg>
        <constructor-arg index="1" name="name" value="王五"></constructor-arg>
    </bean>
</beans>

但是.这种赋值方法还不够完美,那我们就需要换一种更加规范的写法来给对象赋值了:
首先model类的代码如下:

package com.zzx.model;

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class CollectBean {
    /**
     * 案例演示中即是使用的set方法注入.
     * set方法注入 – 注入引用类型
     * set方法注入 – 基本数据类型
     * set方法注入 – 数组
     * set方法注入 – List
     * set方法注入 – Set
     * set方法注入 – Map
     */
    private int base;
    private User user;
    private int[] baseArr;
    private User[] refArr[];
    private List<User> list;
    private Set<User> set;
    private Map<String,Integer> map;

    public int getBase() {
        return base;
    }

    public void setBase(int base) {
        this.base = base;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }

    public int[] getBaseArr() {
        return baseArr;
    }

    public void setBaseArr(int[] baseArr) {
        this.baseArr = baseArr;
    }

    public User[][] getRefArr() {
        return refArr;
    }

    public void setRefArr(User[][] refArr) {
        this.refArr = refArr;
    }

    public List<User> getList() {
        return list;
    }

    public void setList(List<User> list) {
        this.list = list;
    }

    public Set<User> getSet() {
        return set;
    }

    public void setSet(Set<User> set) {
        this.set = set;
    }

    public Map<String, Integer> getMap() {
        return map;
    }

    public void setMap(Map<String, Integer> map) {
        this.map = map;
    }

    public CollectBean(int base, User user, int[] baseArr, User[][] refArr, List<User> list, Set<User> set, Map<String, Integer> map) {
        this.base = base;
        this.user = user;
        this.baseArr = baseArr;
        this.refArr = refArr;
        this.list = list;
        this.set = set;
        this.map = map;
    }

    public CollectBean() {}

    @Override
    public String toString() {
        return "CollectBean{" +
                "base=" + base +
                ", user=" + user +
                ", baseArr=" + Arrays.toString(baseArr) +
                ", refArr=" + Arrays.toString(refArr) +
                ", list=" + list +
                ", set=" + set +
                ", map=" + map +
                '}';
    }
}

然后使用xml来给model雷电的各种属性赋值,XML代码如下:

<?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="collectBean" class="com.zzx.model.CollectBean">
      <!--
          set方法注入,使用<property>标签
          name : 属性名
          value: 基本数据类型赋值
          ref :  引用数据类型赋值,引用的是bean的id
          <array>标签,定义数组的值
       -->
<property name="base" value="28"></property>
<property name="user" ref="user"></property>
<property name="baseArr">
      <array>
            <value>130</value>
            <value>131</value>
            <value>132</value>
      </array>
</property>
<property name="refArr">
      <array>
            <ref bean="user"></ref>
            <ref bean="users"></ref>
      </array>
</property>
<property name="list">
      <list>
            <ref bean="user"/>
            <ref bean="users"/>
            <ref bean="user"/>
            <ref bean="users"/>
      </list>
</property>
<property name="set">
      <set>
            <ref bean="user"/>
            <ref bean="user"/>
            <ref bean="users"/>
            <ref bean="users"/>
      </set>
</property>
<property name="map">
      <map>
           <entry key="张三" value="25"></entry>
            <entry key="李四" value="28"></entry>
      </map>
</property>
</bean>
      <bean id="user" class="com.zzx.model.User">
            <constructor-arg name="age" value="56"></constructor-arg>
            <constructor-arg name="name" value="张三"></constructor-arg>
      </bean>
      <bean id="users" class="com.zzx.model.User">
            <constructor-arg name="age" value="66"></constructor-arg>
            <constructor-arg name="name" value="李四"></constructor-arg>
      </bean>
</beans>

本文地址：https://blog.csdn.net/a1422655169/article/details/114274425