Java之Spring入门到精通【IDEA版】IoC和DI注解开发（二）（一篇文章精通系列

INSERT INTO book VALUES ('5', '11', '11', '11.00', '11');

INSERT INTO book VALUES ('6', '11', '11', '11.00', '11');

INSERT INTO book VALUES ('8', 'JavaScript入门', '刘伟', '55.60', '哈哈');

INSERT INTO book VALUES ('10', 'MySQL从入门到精通', '刘玉徐', '85.00', '???');

---

-- Table structure for user

---

DROP TABLE IF EXISTS user;

CREATE TABLE user (

id int(11) NOT NULL AUTO_INCREMENT,

uname varchar(255) NOT NULL,

upass varchar(255) DEFAULT NULL,

tel varchar(255) NOT NULL,

address varchar(255) NOT NULL,

PRIMARY KEY (id)

) ENGINE=InnoDB AUTO_INCREMENT=124 DEFAULT CHARSET=utf8;

---

-- Records of user

---

INSERT INTO user VALUES ('123', '123', '123', '123', '123');

（4）创建C3P0连接池

package com.itbluebox.db;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import org.junit.Test;

import java.sql.Connection;

public class TestC3P0 {

@Test

public void testC3P0() throws Exception{

//数据源

ComboPooledDataSource dataSource = new ComboPooledDataSource();

//设置数据库连接参数

dataSource.setDriverClass("com.mysql.jdbc.Driver");

dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test");

dataSource.setUser("root");

dataSource.setPassword("root");

//获得连接对象

Connection connection = dataSource.getConnection();

System.out.println(connection);

}

}

运行测试

运行成功

（5）创建Druid连接池

package com.itbluebox.db;

import com.alibaba.druid.pool.DruidDataSource;

import com.alibaba.druid.pool.DruidPooledConnection;

import org.junit.Test;

public class TestDruid {

@Test

public void testDruid() throws Exception{

//创建数据库源

DruidDataSource dataSource = new DruidDataSource();

//设置数据库连接参数

dataSource.setDriverClassName("com.mysql.jdbc.Driver");

dataSource.setUrl("jdbc:mysql://localhost:3306/test");

dataSource.setUsername("root");

dataSource.setPassword("root");

//获取连接对象

DruidPooledConnection connection = dataSource.getConnection();

System.out.println(connection);

}

}

运行成功

3、数据源的手动创建（读取jdbc.properties）

（1）提取jdbc.properties配置文件

jdbc.driver = com.mysql.jdbc.Driver

jdbc.url = jdbc:mysql://localhost:3306/test

jdbc.username = root

jdbc.password = root

（2）读取jdbc.properties配置文件创建连接池

package com.itbluebox.db;

import com.mchange.v2.c3p0.ComboPooledDataSource;

import org.junit.Test;

import java.sql.Connection;

import java.util.ResourceBundle;

public class TestC3P0ByProperties {

@Test

public void C3P0ByProperties() throws Exception{

//加载类路径下的jdbc.properties

ResourceBundle rb = ResourceBundle.getBundle("jdbc");

ComboPooledDataSource dataSource = new ComboPooledDataSource();

dataSource.setDriverClass(rb.getString("jdbc.driver"));

dataSource.setJdbcUrl(rb.getString("jdbc.url"));

dataSource.setUser(rb.getString("jdbc.username"));

dataSource.setPassword(rb.getString("jdbc.password"));

Connection connection = dataSource.getConnection();

System.out.println(connection);

}

}

4、测试从容器当中获取数据源（applicationContext.xml）

（1）创建applicationContext.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: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="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >

<property name="driverClass" value="com.mysql.jdbc.Driver"/>

<property name="jdbcUrl" value="jdbc:mysql://localhost:3306/test"/>

<property name="user" value="root"/>

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

</bean>

</beans>

（2）创建测试类，测试从容器当中获取数据源

package com.itbluebox.db;

import org.junit.Test;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import javax.sql.DataSource;

import java.sql.Connection;

public class TestC3P0Application {

@Test

public void TestC3PO() throws Exception{

ClassPathXmlApplicationContext applicationContext =

new ClassPathXmlApplicationContext("applicationContext.xml");

DataSource dataSource = (DataSource)applicationContext.getBean("dataSource");

Connection connection = dataSource.getConnection();

System.out.println(connection);

}

}

5、抽取jdbc配置文件

（1）修改applicationContext.xml

• applicationContext.xml加载jdbc.properties配置文件获得连接信息。

• 首先，需要引入context命名空间和约束路径：

• 命名空间：xmlns:context="http://www.springframework.org/schema/context"

• 约束路径：

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

http://www.springframework.org/schema/context/spring-context.xsd

• Spring容器加载properties文件

<context:property-placeholder location="xx.properties"/>

<property name="" value="${key}"/>

<?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:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="

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

http://www.springframework.org/schema/context/spring-context.xsd

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

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

<context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >

<property name="driverClass" value="${jdbc.driver}"/>

<property name="jdbcUrl" value="${jdbc.url}"/>

<property name="user" value="${jdbc.username}"/>

<property name="password" value="${jdbc.password}"/>

</bean>

</beans>

运行测试

二、Spring注解开发

---

1、Spring原始注解

Spring是轻代码而重配置的框架，配置比较繁重，影响开发效率，所以注解开发是一种趋势，注解代替xml配置文件可以简化配置，提高开发效率。

• Spring原始注解主要是替代<Bean>的配置

注意：

使用注解进行开发时，需要在applicationContext.xml中配置组件扫描，

作用是指定哪个包及其子包下的Bean

（1）需要进行扫描以便识别使用注解配置的类、字段和方法。

<!--注解的组件扫描-->

<context:component-scan base-package="com.itbluebox">

</context:component-scan>

在这里我们切换回第一篇文章创建的工程Spring-test-demo

<?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:context="http://www.springframework.org/schema/context"

xsi:schemaLocation="

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

http://www.springframework.org/schema/context/spring-context.xsd

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

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

<context:component-scan base-package="com.itbluebox"> </context:component-scan>

</beans>

（2）UserDao：使用@Compont或@Repository标识UserDaoImpl需要Spring进行实例化。

package com.itbluebox.dao.impl;

import com.itbluebox.dao.UserDao;

import org.springframework.stereotype.Component;

@Component("userDao")

public class UserDaoImpl implements UserDao {

public void save() {

System.out.println("UserDao save method running....");

}

}

（3）UserServiceImpl

使用@Compont或@Service标识UserServiceImpl需要Spring进行实例化

使用@Autowired或者@Autowired+@Qulifier或者@Resource进行userDao的注入

package com.itbluebox.service.impl;

import com.itbluebox.dao.UserDao;

import com.itbluebox.service.UserService;

import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service("userService")

public class UserServiceImpl implements UserService {

/*

@Autowired

@Qualifier("userDao")

*/

@Resource(name="userDao")

private UserDao userDao;

public void setUserDao(UserDao userDao) {

this.userDao = userDao;

}

public void save() {

System.out.println("UserServiceImpl save method running....");

userDao.save();

}

}

（4）创建UserController

package com.itbluebox.web;

import com.itbluebox.service.UserService;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserController {

public static void main(String[] args) {

ClassPathXmlApplicationContext app = new ClassPathXmlApplicationContext("applicationContext.xml");

UserService userService = app.getBean(UserService.class);

userService.save();

}

}

运行测试

（5）使用@Value进行字符串的注入

• 引入依赖

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

<project xmlns="http://maven.apache.org/POM/4.0.0"

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

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.itbluebox</groupId>

<artifactId>spring-test-demo</artifactId>

<version>1.0.0-SNAPSHOT</version>

<properties>

<spring.version>5.0.5.RELEASE</spring.version>

</properties>

<dependencies>

<!--导入spring的context坐标，context依赖core、beans、expression-->

<dependency>

<groupId>org.springframework</groupId>

<artifactId>spring-context</artifactId>

<version>${spring.version}</version>

</dependency>

<!-- C3P0连接池 -->

<dependency>

<groupId>c3p0</groupId>

<artifactId>c3p0</artifactId>

<version>0.9.1.2</version>

</dependency>

<!-- Druid连接池 -->

<dependency>

<groupId>com.alibaba</groupId>

<artifactId>druid</artifactId>

<version>1.1.10</version>

</dependency>

<!-- mysql驱动 -->

<dependency>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

<version>5.1.39</version>

</dependency>

<dependency>

<groupId>junit</groupId>

<artifactId>junit</artifactId>

<version>4.12</version>

<scope>test</scope>

</dependency>

</dependencies>

</project>

• 创建jdbc.properties

• 完善applicationContext.xml配置文件

<?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:p="http://www.springframework.org/schema/p"

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

xsi:schemaLocation="

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

http://www.springframework.org/schema/context/spring-context.xsd

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

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

<context:property-placeholder location="classpath:jdbc.properties"></context:property-placeholder>

<!--注解的组件扫描-->

<context:component-scan base-package="com.itbluebox"></context:component-scan>

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" >

<property name="driverClass" value="${jdbc.driver}"/>

<property name="jdbcUrl" value="${jdbc.url}"/>

<property name="user" value="${jdbc.username}"/>

<property name="password" value="${jdbc.password}"/>

</bean>

</beans>

• 完善UserDaoImpl

package com.itbluebox.dao.impl;

import com.itbluebox.dao.UserDao;

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

import org.springframework.stereotype.Component;

@Component("userDao")

public class UserDaoImpl implements UserDao {

@Value("注入普通数据")

private String str;

@Value("${jdbc.driver}")

private String driver;

public void save() {

System.out.println(str);

System.out.println(driver);

System.out.println("UserDao save method running....");

}

}

• 运行测试

（6）使用@Scope标注Bean的范围

@Scope("singleton")

（7）使用@PostConstruct标注初始化方法，使用@PreDestroy标注销毁方法

完善UserServiceImpl

package com.itbluebox.service.impl;

import com.itbluebox.dao.UserDao;

import com.itbluebox.service.UserService;

import org.springframework.context.annotation.Scope;

import org.springframework.stereotype.Service;

import javax.annotation.PostConstruct;

import javax.annotation.PreDestroy;

import javax.annotation.Resource;

@Service("userService")

@Scope("singleton")

public class UserServiceImpl implements UserService {

/*

@Autowired

@Qualifier("userDao")

*/

@Resource(name="userDao")

private UserDao userDao;

public void setUserDao(UserDao userDao) {

this.userDao = userDao;

}

public void save() {

System.out.println("UserServiceImpl save method running....");

userDao.save();

}

@PostConstruct

public void init(){

System.out.println("初始化方法。。。。");

}

@PreDestroy

public void destroy(){

System.out.println("销毁方法。。。。");

}

}

• 完善UserController，添加app.close()

package com.itbluebox.web;

import com.itbluebox.service.UserService;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class UserController {

public static void main(String[] args) {

ClassPathXmlApplicationContext app =

new ClassPathXmlApplicationContext("applicationContext.xml");

UserService userService = app.getBean(UserService.class);

userService.save();

app.close();

}

}

• 运行测试

3、Spring新注解

使用上面的注解还不能全部替代xml配置文件，还需要使用注解替代的配置如下：

非自定义的Bean的配置：<bean>

加载properties文件的配置：<context:property-placeholder>

组件扫描的配置：<context:component-scan>

引入其他文件：<import>

（1）创DataSourceConfiguration

package com.itbluebox.config;

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

import org.springframework.context.annotation.PropertySource;

@PropertySource("classpath:jdbc.properties")

public class DataSourceConfiguration {

@Value("${jdbc.driver}")

private String driver;

@Value("${jdbc.url}")

private String url;

@Value("${jdbc.username}")

private String username;

@Value("${jdbc.password}")

private String password;

@Bean(name = "dataSource")

private DataSource getDataSource() throws PropertyVetoException{

ComboPooledDataSource dataSource = new ComboPooledDataSource();

dataSource.setDriverClass(driver);

dataSource.setJdbcUrl(url);

dataSource.setUser(username);

dataSource.setPassword(password);

return dataSource;

}

}

（2）创建SpringConfiguration

@Configuration

@ComponentScan

@Import

package com.itbluebox.config;

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