Spring的基本使用方法
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2022-03-30 11:21:00
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.printl...
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