前言：
spring boot就是整合了很多优秀的框架，不用我们自己手动的去写一堆xml配置然后进行配置。有了它， 你可以更加敏捷地开发Spring应用程序，专注于应用程序的功能，不用在Spring的配置上多花功 夫，甚至完全不用配置。
一 spring4.x的java注解方式编程
Java注解是Spring4.x推荐的配置方式，可以完全替代xml配置。Spring的Java注解方式是通过 @Configuration和 @Bean这两个注解实现的：
1、@Configuration 作用于类上，相当于一个xml配置文件；
2、@Bean 作用于方法上，相当于xml配置中的<bean>；
上案例！！！
开发环境:spring4.3.9+jdk1.7+maven3.6+eclipse mars.2+mysql
结构图：
pom.xml配置如下:
<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>org.lzq</groupId>
<artifactId>springboot</artifactId>
<version>0.0.1-SNAPSHOT</version>
<properties>
<!-- jar包统一升级管理 -->
<spring.version>4.3.9.RELEASE</spring.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-expression</artifactId>
<version>${spring.version}</version>
</dependency>
<!-- 日志包 -->
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<!-- mysql连接驱动包 -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.26</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.7</source>
<target>1.7</target>
<encoding>utf-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
</project>
实体类:UserEntity.java
package org.lzq.entity;
import java.io.Serializable;
public class UserEntity implements Serializable {
private static final long serialVersionUID = -5425731832559669953L;
private Integer userId;
private String userName;
private String passWord;
public UserEntity() {
super();
}
public UserEntity(Integer userId, String userName, String passWord) {
super();
this.userId = userId;
this.userName = userName;
this.passWord = passWord;
}
public Integer getUserId() {
return userId;
}
public void setUserId(Integer userId) {
this.userId = userId;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
}
dao层代码:
IUserDao.java
package com.accp.dao;
import java.util.List;
import org.lzq.entity.UserEntity;
public interface IUserDao {
//查询所有
List<UserEntity> queryAll();
}
UserDaoImpl.java
package com.lyc.dao;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import org.springframework.stereotype.Repository;
import com.lyc.entity.UserEntity;
@Repository("userDao")
public class UserDaoImpl extends BaseDao implements IUserDao{
@Override
public List<UserEntity> queryAll() {
List<UserEntity> list = new ArrayList<UserEntity>();
String sql= "select * from users";
rs = executeQuery(sql);
try {
UserEntity user=null;
while(rs.next()){
user=new UserEntity();
user.setUserId(rs.getInt("userId"));
user.setUserName(rs.getString("userName"));
user.setPassWord(rs.getString("passWord"));
list.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
closeAll();
}
return list;
}
}
业务层代码
UserService.java
package com.lyc.service;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
import com.lyc.dao.IUserDao;
import com.lyc.entity.UserEntity;
@Service("userService")
public class UserService {
//Autowired默认根据类型进行装配，加上Qualifier注解则变成根据名称装配
@Autowired
@Qualifier("userDao")
private IUserDao userDao;
public List<UserEntity> queryAll() {
return userDao.queryAll();
}
}
配置类
SpringConfig.java
package com.lyc.configs;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import com.lyc.dao.IUserDao;
import com.lyc.dao.UserDaoImpl;
//通过该注解来表明该类是一个Spring的配置，相当于一个传统的ApplicationContext.xml
@Configuration
//相当于配置文件里面的<context:component-scan/>标签
@ComponentScan(basePackages="com.lyc.dao,com.lyc.service")
public class SpringConfig {
// 通过该注解来表明是一个Bean对象，相当于xml中的<bean>
//bean的id值默认是方法名userDao
/*
@Bean
public IUserDao userDao(){
return new UserDaoImpl();
}
*/
}
测试类代码
Test01.java
package com.lyc.test;
import java.util.List;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import com.lyc.configs.SpringConfig;
import com.lyc.entity.UserEntity;
import com.lyc.service.UserService;
public class Test01 {
public static void main(String[] args) {
//通过java配置来实例化spring容器
AnnotationConfigApplicationContext acac =
new AnnotationConfigApplicationContext(SpringConfig.class);
//在spring容器中获取bean对象
//名称userService是注解根据类UserService自动生成的
UserService userService = (UserService) acac.getBean("userService");
//或者采取下面的方式
//UserService userService = acac.getBean(UserService.class);
List<UserEntity> list = userService.queryAll();
for (UserEntity u : list) {
System.out.println(u.getUserName()+"---"+u.getPassWord());
}
//销毁容器
acac.destroy();
}
}
感觉还是挺简单的哈！！！
原文地址：https://www.cnblogs.com/chao123/p/10214644.html
时间： 2024-10-08 23:17:47