Spring Boot 2.5.0

//在项目中的包结构中创建入口类 Application
/*
* 这个注解的修饰范围：用在类上，只能用在入口类，只能出现一次
* 作用：标识这个类是一个springboot入口类，启动springboot项目的总入口
* */
    @SpringBootApplication
    public class Application {
      public static void main(String[] args) {
      //启动springboot应用 参数1：指定入口类的类对象.class  参数2：main函数参数
        SpringApplication.run(Application.class,args);
      }
    }

o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
com.baizhi.Application : Started Application in 2.152 seconds (JVM running for 2.611)
//说明:  出现以上日志说明启动成功

//在项目中创建指定的包结构
/*
	 com
	    +| baizhi
	    		+| controller */ 
                	@Controller
                  @RequestMapping("/hello")
                  public class HelloController {
                    @RequestMapping("/hello")
                    @ResponseBody
                    public String hello(){
                      	System.out.println("======hello world=======");
                      return "hello";
                     }
                  }
               	    		  		

@Service
public class DemoServiceImpl implements UserService{
  //doing....
}	

@Controller
@RequestMapping("hello")
public class HelloController {
    @Autowired
    private DemoService demoService;
    //doing...
}

@Configuration
public class Beans {
    @Bean
    public Calendar calendar(){
        return Calendar.getInstance();
    }
}

@Controller
@RequestMapping("hello")
public class HelloController {
    @Autowired
    private Calendar calendar;
    ......
}

@RestController
public class HelloController {
    //基本类型+String类型+日期类型
  	@Value("${name}")
    private String name;
    @Value("${age}")
    private Integer age;
    @Value("${sex}")
    private Boolean sex;
    @Value("${price}")
    private Double price;
    @Value("${bir}")
    private Date bir;
		//注入数组
    @Value("${qqs}")
    private String[] qqs;
  	//注入list
    @Value("${lists}")
    private List<String> lists;
  	//注入maps
    @Value("#{${maps}}")
    private Map<String,String> maps;
}

@Component
@ConfigurationProperties(prefix = "user")
public class User {
    private String id;
    private String name;
    private Integer age;
    private String  bir;
    //set 方法一定要提供
}

//入口类中加入如下配置:
@SpringBootApplication
@MapperScan("com.baizhi.dao")   //必须在入口类中加入这个配置
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

public class Clazz {
    private String id;
    private String name;
    private String no;
    //get set 方法省略....
}

public interface ClazzDAO {
    List<Clazz> findAll();
}

//接口
public interface ClazzService {
    List<Clazz> findAll();
}
//实现
@Service
@Transactional
public class ClazzServiceImpl implements  ClazzService {
    @Autowired
    private ClazzDAO clazzDAO;
   
    @Transactional(propagation = Propagation.SUPPORTS)
    @Override
    public List<Clazz> findAll() {
        return clazzDAO.findAll();
    }
}

@RestController
public class ClazzController {
    @Autowired
    private ClazzService clazzService;
  
    //查询所有
    @RequestMapping("findAll")
    public List<Clazz> findAll(){
        return clazzService.findAll();
    }   
}

@SpringBootTest
public class TestEmpService {

    @Autowired
    private EmpService empService;

    @Test
    public void test(){
        empService.findAll().forEach(emp-> System.out.println(emp));
    }
}

@Controller
public class HelloController {
    //声明日志成员
    private static final Logger log = LoggerFactory.getLogger(HelloController.class);
    @RequestMapping("/hello")
    @ResponseBody
    public String hello(){
        System.out.println("======hello world=======");
        logger.debug("DEBUG,{}","信息");
        logger.info("INFO,{}","信息");
        logger.warn("WARN,{}","信息");
        logger.error("ERROR,{}","信息");
        return "hello";
    }
}

@Aspect
@Configuration //表示该类为配置类
public class MyAspect {
    @Before("execution(* com.baizhi.service.*.*(..))")
    public void before(JoinPoint joinPoint){
        System.out.println("前置通知");
        joinPoint.getTarget();//目标对象
        joinPoint.getSignature();//方法签名
        joinPoint.getArgs();//方法参数
    }
}

@Aspect
@Configuration
public class MyAspect {
    @After("execution(* com.baizhi.service.*.*(..))")
    public void before(JoinPoint joinPoint){
        System.out.println("后置通知");
        joinPoint.getTarget();//目标对象
        joinPoint.getSignature();//方法签名
        joinPoint.getArgs();//方法参数
    }
}

@Aspect
@Configuration
public class MyAspect {
    @Around("execution(* com.baizhi.service.*.*(..))")
    public Object before(ProceedingJoinPoint proceedingJoinPoint) throws Throwable {
        System.out.println("进入环绕通知");
        proceedingJoinPoint.getTarget();//目标对象
        proceedingJoinPoint.getSignature();//方法签名
        proceedingJoinPoint.getArgs();//方法参数
        Object proceed = proceedingJoinPoint.proceed();//放行执行目标方法
        System.out.println("目标方法执行之后回到环绕通知");
        return proceed;//返回目标方法返回值
    }
}

@Controller
@RequestMapping("/file")
public class FileController {
  @RequestMapping("/upload")
  public String upload(MultipartFile aa, HttpServletRequest request) throws IOException {
        String realPath = request.getRealPath("/upload");
        aa.transferTo(new File(realPath,aa.getOriginalFilename()));//文件上传
        return "index";
  }
}

@Slf4j
@Controller
@RequestMapping("/file")
public class FileController {

    @Value("${file.download.dir}")
    private String realPath;

    /**
     * 文件下载
     */
    @RequestMapping("download")
    public void download(String fileName, HttpServletResponse response) throws IOException {
        log.debug("下载的文件名为：{}",fileName);
        log.debug("文件下载的目录为：{}",realPath);
        //1.到指定目录读取文件
       File file = new File(realPath,fileName);
       //2.将文件读取为文件输入流
        FileInputStream inputStream = new FileInputStream(file);
        //2.5获取响应流之前，要设置以附件形式下载,防止直接在浏览器打开文件
        response.setHeader("content-disposition","attachment;fileName="+
                URLEncoder.encode(fileName,"UTF-8")); //防止下载时中文乱码指定编码
        //3.获取响应输出流
        ServletOutputStream outputStream = response.getOutputStream();
        //4.输入流复制给输出流
       /* int len=0;
        byte[] b=new byte[1024];
        while (true){
            len=inputStream.read(b);
            if (len==-1) break;
            outputStream.write(b,0,len);
        }
        //5.释放资源
        inputStream.close();
        outputStream.close();*/
        //简化（替换）4、5两步
        FileCopyUtils.copy(inputStream,outputStream); //springboot自带的将输入流拷贝给输出流的工具
    }
}

@RequestMapping("/download")
public void download(String fileName, HttpServletRequest request, HttpServletResponse response) throws Exception {
        String realPath = request.getRealPath("/upload");
        FileInputStream is = new FileInputStream(new File(realPath, fileName));
        ServletOutputStream os = response.getOutputStream();
        response.setHeader("content-disposition","attachment;fileName="+ URLEncoder.encode(fileName,"UTF-8"));
        IOUtils.copy(is,os);
        IOUtils.closeQuietly(is);
        IOUtils.closeQuietly(os);
    }

public class MyInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        System.out.println("======1=====");
        return true;//返回true 放行  返回false阻止
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("=====2=====");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object o, Exception e) throws Exception {
        System.out.println("=====3=====");
    }
}

@Configuration
public class WebMvcConfig  implements WebMvcConfigurer {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
      	registry.addInterceptor("拦截器")
                .addPathPatterns("拦截路径")
                .excludePathPatterns("排除路径")
          			.order("指定执行顺序")
    }
}

//1.继承SpringBootServletInitializer
//2.覆盖configure方法
public class Application extends SpringBootServletInitializer{
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
    @Override
    protected SpringApplicationBuilder configure(SpringApplicationBuilder builder) {
        return builder.sources(Application.class);
    }
}

@Controller    //一定要是@Controller 不能再使用@RestController注解
@RequestMapping("hello")
public class HelloController {
    @GetMapping("hello")
    public String hello(){
        System.out.println("测试与 thymeleaf 的集成");
        return "index";
    }
}

package com.meng.controller;

import com.meng.entity.User;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpServletRequest;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;

@Controller
@RequestMapping("demo")
public class DemoController {

    /**
     * forword调转： request model 作用域
     * redirect调转： session作用域
     * 1.传递单个数据：string、integer....
     * 2.传递对象类型： user
     * 3.传递集合类型
     * 4.如何在页面有条件的展示数据    判断
     * @return
     */
    @RequestMapping("demo")
    public String demo(HttpServletRequest request, Model model, HttpSession session){

        //传递单个类型的数据
        System.out.println("demo ok");
        String name="李思思";
        Integer age=24;
        String content="<a href='http://www.baidu.com'>百度一下</a>";
        request.setAttribute("name",name);
        model.addAttribute("age",age);
        model.addAttribute("content",content);


        //传递对象类型的数据
        User user = new User(1,"李思思",8900.00,new Date());
        request.setAttribute("user",user);

        //传递集合类型数据   Arrays：集合工具类
        List<User> users= Arrays.asList(new User(2,"李萌萌",8500.00,new Date()),
                                        new User(3,"李小小",8500.00,new Date()),
                                        new User(4,"李陌陌",8500.00,new Date()));

        model.addAttribute("users",users);

  //session作用域传递数据
  session.setAttribute("xxname","梨花");
       return "demo";
    }
}

model.addAttribute("name","张三"); 或 request.setAttribute("name","小黑");

model.addAttribute("name","<a href=''>张三</a>");
model.addAttribute("username","小陈");