需求背景：
1、項(xiàng)目啟動(dòng)時(shí)友酱，加載緩存
2晴音、項(xiàng)目啟動(dòng)時(shí)，開(kāi)啟對(duì)外服務(wù)端
一缔杉、InitializingBean實(shí)現(xiàn)
InitializingBean簡(jiǎn)介：
InitializingBean是Spring提供的拓展性接口锤躁，InitializingBean接口為bean提供了屬性初始化后的處理方法，它只有一個(gè)afterPropertiesSet方法或详，凡是繼承該接口的類(lèi)系羞，在bean的屬性初始化后都會(huì)執(zhí)行該方法。
InitializingBean用法：
package com.pcf.spdemo.configuration;
import com.pcf.spdemo.common.httpserver.NettyServer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class BeanInit implements InitializingBean {
private static Logger log = LoggerFactory.getLogger(BeanInit.class);
@Autowired
private NettyServer nettyServer;
@Override
public void afterPropertiesSet() throws Exception {
log.info("netty----------------------------------");
init();
}
private void init() {
/** 另起一個(gè)線程器啟動(dòng)netty霸琴，主線程繼續(xù)啟動(dòng)項(xiàng)目 **/
new Thread(){
@Override
public void run() {
nettyServer.start();
}
}.start();
log.info("netty對(duì)外服務(wù)端已啟動(dòng)...");
}
}
效果圖：
1.PNG
二椒振、@PostConstruct注解實(shí)現(xiàn)
@PostContruct是JDK自帶的注解，用來(lái)修飾非靜態(tài)void方法梧乘。spring初始化該bean后杠人，會(huì)執(zhí)行bean中的該方法。
示例代碼：
package com.pcf.spdemo.configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
@Component
public class InitCache {
private static Logger log = LoggerFactory.getLogger(InitCache.class);
@PostConstruct
public void init() {
log.info("通過(guò)@PostConstruct注解宋下，實(shí)現(xiàn)項(xiàng)目啟動(dòng)時(shí)加載緩存...");
}
}
效果展示：
2.PNG
三嗡善、通過(guò)配置@bean的init-method屬性實(shí)現(xiàn)
代碼實(shí)現(xiàn)：
package com.pcf.spdemo.configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
@Component
public class InitCache {
private static Logger log = LoggerFactory.getLogger(InitCache.class);
@Bean(initMethod = "init")
public void init() {
log.info("通過(guò)配置@bean的init-method屬性，實(shí)現(xiàn)項(xiàng)目啟動(dòng)時(shí)加載緩存...");
}
}
效果展示：
3.PNG
四学歧、通過(guò)bean構(gòu)造方法實(shí)現(xiàn)
bean初始化時(shí)實(shí)現(xiàn)罩引。（沒(méi)見(jiàn)用過(guò)，最好別用這種方式）
代碼實(shí)例：
package com.pcf.spdemo.configuration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
@Component
public class InitCache {
private static Logger log = LoggerFactory.getLogger(InitCache.class);
public InitCache() {
init();
}
public void init() {
log.info("通過(guò)放入bean構(gòu)造方法枝笨，實(shí)現(xiàn)項(xiàng)目啟動(dòng)時(shí)加載緩存...");
}
}
效果展示：
4.PNG
五袁铐、四種方式優(yōu)先級(jí)比較
測(cè)試代碼：
package com.pcf.spdemo.configuration;
import com.pcf.spdemo.common.httpserver.NettyServer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import javax.annotation.PostConstruct;
@Component
public class BeanInit implements InitializingBean {
private static Logger log = LoggerFactory.getLogger(BeanInit.class);
@Autowired
private NettyServer nettyServer;
public BeanInit() {
init2();
}
@Override
public void afterPropertiesSet() throws Exception {
log.info("netty----------------------------------");
init();
}
private void init() {
/** 另起一個(gè)線程器啟動(dòng)netty，主線程繼續(xù)啟動(dòng)項(xiàng)目 **/
new Thread(){
@Override
public void run() {
nettyServer.start();
}
}.start();
log.info("netty對(duì)外服務(wù)端已啟動(dòng)...");
}
@PostConstruct
public void init1() {
log.info("通過(guò)@PostConstruct注解横浑，實(shí)現(xiàn)項(xiàng)目啟動(dòng)時(shí)加載緩存...");
}
public void init2() {
log.info("通過(guò)放入bean構(gòu)造方法剔桨，實(shí)現(xiàn)項(xiàng)目啟動(dòng)時(shí)加載緩存...");
}
@Bean(initMethod = "init")
public void init3() {
log.info("通過(guò)配置@bean的init-method屬性，實(shí)現(xiàn)項(xiàng)目啟動(dòng)時(shí)加載緩存...");
}
}
測(cè)試結(jié)果展示：
5.PNG
由此可以看出：
優(yōu)先級(jí)： 構(gòu)造方法 > @PostContruct > afterPropertiesSet() > init-method
