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

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 */@Configurationpublic 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 */@RestControllerpublic class HomeController {    @RequestMapping("/")    public Student home(){        Student student = new Student(1,"zhangsan",12);        return student;    }}

访问浏览器

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

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 */@ControllerAdvicepublic 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

创建定时任务

新加注解 @EnableScheduling

@SpringBootApplication@EnableSchedulingpublic 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 */@Componentpublic 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

@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