项目依赖
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| <parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.2.5.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
</dependencies>
|
1. 全局配置
写法1
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| @SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication sa = new SpringApplication(Application.class);
sa.setLazyInitialization(true);
sa.run(args);
}
}
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写法2
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| @SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplicationBuilder sab = new SpringApplicationBuilder(Application.class);
sab.lazyInitialization(true).run(args);
}
}
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写法3
直接在application.yml文件中
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| spring:
main:
lazy-initialization: true
|
展示效果
Controller层代码
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| package com.lx.controller;
import com.lx.service.IndexService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import lombok.extern.slf4j.Slf4j;
@Slf4j
@Lazy(false)
@RestController
public class IndexController {
public IndexController() {
log.info("[{}]开始初始化", IndexController.class);
}
@Autowired
private IndexService indexService;
@GetMapping("/")
public String index() {
indexService.index();
return "success";
}
}
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Service层代码
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| package com.lx.service;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Service;
import lombok.extern.slf4j.Slf4j;
@Slf4j
@Lazy
@Service
public class IndexService {
public IndexService() {
log.info("[{}]开始初始化", IndexService.class);
}
public void index() {
log.info("index method run");
}
}
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展示效果
启动项目后打印日志
访问localhost:8080后打印的日志
配置成功
2. 局部类/方法配置
想要实现局部类/方法的懒加载很简单，只需要在类/方法上添加@Lazy注解即可，默认值true开启懒加载，不开启可设置为false，例如：想要懒加载IndexController那么只需要在类上添加@Lazy。注：我这里在展示局部实现效果时，项目中以去除全局懒加载的配置
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| package com.lx.controller;
import com.lx.service.IndexService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Lazy;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import lombok.extern.slf4j.Slf4j;
@Lazy
@Slf4j
@RestController
public class IndexController {
public IndexController() {
log.info("[{}]开始初始化", IndexController.class);
}
@Autowired
private IndexService indexService;
@GetMapping("/")
public String index() {
indexService.index();
return "success";
}
}
|
启动项目打印日志
调用localhost:8080接口后打印的日志
注：当设置懒加载的类/方法有被其他类初始化注入时，如果注入此类/方法的类没有设置懒加载的话，在启动时一样会被初始话。例如：给IndexService添加@Lazy懒加载注解，然后去掉IndexController的懒加载注解后再启动项目查看日志
局部配置比全局配置优先级要高
在application.yml中设置开启全局懒加载配置
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| spring:
main:
lazy-initialization: true
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给IndexService通过@Lazy设置禁用懒加载
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| package com.lx.service;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Service;
import lombok.extern.slf4j.Slf4j;
@Lazy
@Slf4j
@Service
public class IndexService {
public IndexService() {
log.info("[{}]开始初始化", IndexService.class);
}
public void index() {
log.info("index method run");
}
}
|
启动项目查看日志打印，可以看到IndexService在项目启动时就进行了初始化，而IndexController在启动时并没有进行初始化
参考博客：https://juejin.im/post/5e83f795f265da47e449f4ea
作者: 只是学习学习
邮箱: fengzxia1000@163.com
原文地址: https://fengzxia.gitee.io/posts/53d4b364.html
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