springboot系列文章（四）——fastjson、定时任务、全局异常配置

柔光的暖阳◎ 2022-06-03 07:44 296阅读 0赞

## **配置其它json框架** ##

***引入maven依赖***

<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.37</version>
            </dependency>

***新建WebMvcConfigurer类***

package com.example.demo.config;
    
    import com.alibaba.fastjson.serializer.SerializerFeature;
    import com.alibaba.fastjson.support.config.FastJsonConfig;
    import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.http.converter.HttpMessageConverter;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    
    import java.util.List;
    
    /** * @author :小虎 * @date :2017/12/22 */
    
    
    @Configuration
    public class WebMvcConfigurer extends WebMvcConfigurerAdapter { 
        @Override
        public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
            FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();
            //自定义配置...
            FastJsonConfig config = new FastJsonConfig();
            config.setSerializerFeatures(SerializerFeature.PrettyFormat);
            //config.set ...
            converter.setFastJsonConfig(config);
            converters.add(converter);
        }
    }

***新建model类***

package com.example.demo.Controller;
    
    import com.alibaba.fastjson.annotation.JSONField;
    
    /** * @author :小虎 * @date :2017/12/22 */
    
    
    public class Student { 
        @JSONField(serialize = false)
        private int id;
        private String name;
        private int age;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    
    
        public Student(int id, String name, int age) {
            this.id = id;
            this.name = name;
            this.age = age;
        }
    }

新建controller

package com.example.demo.Controller;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    /** * @author :小虎 * @date :2017/12/22 */
    
    
    @RestController
    public class HomeController { 
    
        @RequestMapping("/")
        public Student home(){
            Student student = new Student(1,"zhangsan",12);
            return student;
        }
    }

***访问浏览器***  
![这里写图片描述][SouthEast]

> 没有id表示使用fastjson成功

**参考网址**

> [https://github.com/alibaba/fastjson/wiki/%E5%9C%A8-Spring-%E4%B8%AD%E9%9B%86%E6%88%90-Fastjson][https_github.com_alibaba_fastjson_wiki_E5_9C_A8-Spring-_E4_B8_AD_E9_9B_86_E6_88_90-Fastjson]

## **全局异常配置** ##

**新建GlobalDefaultExceptionHandler类**

import org.springframework.ui.Model;
    import org.springframework.web.bind.WebDataBinder;
    import org.springframework.web.bind.annotation.*;
    
    import java.util.HashMap;
    import java.util.Map;
    
    /** * @author :小虎 * @date :2017/12/22 */
    
    @ControllerAdvice
    public class GlobalDefaultExceptionHandler { 
    
    
        /** * 应用到所有@RequestMapping注解方法，在其执行之前初始化数据绑定器 * @param binder */
        @InitBinder
        public void initBinder(WebDataBinder binder) {}
    
        /** * 把值绑定到Model中，使全局@RequestMapping可以获取到该值 * @param model */
        @ModelAttribute
        public void addAttributes(Model model) {
            model.addAttribute("author", "Magical Sam");
        }
    
        /** * 全局异常捕捉处理 * @param ex * @return */
        @ResponseBody
        @ExceptionHandler(value = Exception.class)
        public Map errorHandler(Exception ex) {
             /* *返回json数据或者String数据： *那么需要在方法上加上注解：@ResponseBody *添加return即可。 */
    
           /* *返回视图： *定义一个ModelAndView即可， *然后return; *定义视图文件(比如：error.html,error.ftl,error.jsp); * */
            Map map = new HashMap();
            map.put("code", 200);
            map.put("msg", ex.getMessage());
            return map;
        }
    
        /** * 拦截捕捉自定义异常 MyException.class * @param ex * @return */
        @ResponseBody
        @ExceptionHandler(value = MyException.class)
        public Map myErrorHandler(MyException ex) {
            Map map = new HashMap();
            map.put("code", ex.getCode());
            map.put("msg", ex.getMsg());
            return map;
        }
    }

**新建MyException**

package com.example.demo.handler;
    
    /** * @author :小虎 * @date :2017/12/22 */
    
    
    public class MyException extends RuntimeException { 
    
        public MyException(String code, String msg) {
            this.code = code;
            this.msg = msg;
        }
    
        private String code;
        private String msg;
    
        public String getCode() {
            return code;
        }
    
        public void setCode(String code) {
            this.code = code;
        }
    
        public String getMsg() {
            return msg;
        }
    
        public void setMsg(String msg) {
            this.msg = msg;
        }
    
    
    }

**新增连接**

@RequestMapping("/zeroException")
        public int zeroException(){
            return 100/0;
        }
    
        @RequestMapping("/myException")
        public int myException(){
            throw  new MyException("100","codeError");
        }

**访问结果**  
![这里写图片描述][SouthEast 1]

## **创建定时任务** ##

**新加注解 @EnableScheduling**

@SpringBootApplication
    @EnableScheduling
    public class Study4Application { 
    
        public static void main(String[] args) {
            SpringApplication.run(Study4Application.class, args);
        }
    }

**新建定时任务类**

package com.example.demo.task;
    
    import org.springframework.scheduling.annotation.Scheduled;
    import org.springframework.stereotype.Component;
    
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    /** * @author :小虎 * @date :2017/12/25 */
    
    
    @Component
    public class ScheduledTasks { 
    
        private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
    
        @Scheduled(fixedRate = 5000)
        public void reportCurrentTime() {
            System.out.println("现在时间：" + dateFormat.format(new Date()));
        }
    
    }

**输出**  
![这里写图片描述][SouthEast 2]  
**@Scheduled详解**

> **在上面的入门例子中，使用了@Scheduled(fixedRate = 5000) 注解来定义每过5秒执行的任务，对于@Scheduled的使用可以总结如下几种方式：**
> 
> **@Scheduled(fixedRate = 5000)** ：上一次开始执行时间点之后5秒再执行  
> **@Scheduled(fixedDelay = 5000)** ：上一次执行完毕时间点之后5秒再执行  
> **@Scheduled(initialDelay=1000, fixedRate=5000)** ：第一次延迟1秒后执行，之后按fixedRate的规则每5秒执行一次  
> **@Scheduled(cron=”\*/5 \* \* \* \* \*”)** ：通过cron表达式定义规则

## 源码地址 ##

> [https://github.com/itmybaby/springboot/tree/master/study4][https_github.com_itmybaby_springboot_tree_master_study4]

[SouthEast]: /images/20220603/d6556bb5f0cc45a1b1c77f5177c1cf46.png
[https_github.com_alibaba_fastjson_wiki_E5_9C_A8-Spring-_E4_B8_AD_E9_9B_86_E6_88_90-Fastjson]: https://github.com/alibaba/fastjson/wiki/%E5%9C%A8-Spring-%E4%B8%AD%E9%9B%86%E6%88%90-Fastjson
[SouthEast 1]: /images/20220603/3af2b9bb7975400587b8039d7530e463.png
[SouthEast 2]: /images/20220603/93a0081176cd4e37aa83f8afe75ceb32.png
[https_github.com_itmybaby_springboot_tree_master_study4]: https://github.com/itmybaby/springboot/tree/master/study4