Spring Boot 学习记录

记录 Spring Boot 学习过程

Maven 打包注意事项

配置文件变量替换
- 在 SpringBoot 中使用 Maven 的 resource-filter 时配置文件内的变量应该由 ${project.version} 改为 @project.version@

读取配置

在 Bean 上添加注解
- @Component
- @ConfigurationProperties(prefix = "sms")
在需要使用的地方添加@Autowired即可

配置部分 application.yml

sms:
  regionId: 'cn-hangzhou'
  accessKeyId: '****************'
  secret: '****************'
  endpointName: 'cn-hangzhou'
  product: 'Sms'
  domain: 'sms.aliyuncs.com'
  sign: 'XX科技'

代码部分 SmsSetting.java

@Component
@ConfigurationProperties(prefix = "sms")
public class SmsSetting {
    private String regionId;
    private String accessKeyId;
    private String secret;
    private String endpointName;
    private String product;
    private String domain;
    private String sign;
}

读取自定义文件配置

在 Bean 上添加注解
- @Component
- @ConfigurationProperties(prefix = "git.commit", exceptionIfInvalid = false)
- @PropertySource("classpath:git.properties")
@PropertySource 配置的是文件路径

配置文件部分

#Generated by Git-Commit-Id-Plugin
#Fri Sep 15 14:03:50 CST 2017
git.branch=release
git.build.host=SDWM--20090101U
git.build.time=2017-09-15T14\:03\:50+0800
git.build.user.email=admin@yumc.pw
git.build.user.name=502647092
git.build.version=1.5.0
git.closest.tag.commit.count=
git.closest.tag.name=
git.commit.id=45066a3aba4a698f99e236ac2b90843a97045467
git.commit.id.abbrev=45066a3
git.commit.id.describe=45066a3-dirty
git.commit.id.describe-short=45066a3-dirty
git.commit.message.full=feat\: \u610F\u89C1\u53CD\u9988\u6DFB\u52A0\u9A8C\u8BC1\u7801
git.commit.message.short=feat\: \u610F\u89C1\u53CD\u9988\u6DFB\u52A0\u9A8C\u8BC1\u7801
git.commit.time=2017-09-15T09\:47\:01+0800
git.commit.user.email=admin@yumc.pw
git.commit.user.name=502647092
git.dirty=true
git.remote.origin.url=http\://192.168.0.18\:3000/DesignPlatform/DesignPlatformService
git.tags=

代码部分

@Data
@Component
@ConfigurationProperties(prefix = "git.commit", exceptionIfInvalid = false)
@PropertySource("classpath:git.properties")
public class GitInfo {
    private Id id;
    private Message message;
    private User user;

    @Data
    public static class Id {
        String abbrev;
        String describe;
        String describeShort;
    }

    @Data
    public static class Message {
        private String full;
        // 由于 short 是Java关键词 所以这里改为大写
        // Spring 可以识别 标准驼峰 横杠 和 全大写
        private String Short;
    }

    @Data
    public static class User {
        private String email;
        private String name;
    }
}

参数验证

需要验证的 Entity 字段添加验证注解 @NotEmpty 还有更多的注解详见验证注解

public class Demand {
    private Integer id;
    @NotEmpty(message = "需求标题不得为空")
    private String title;
    @NotNull(message = "需求样式不得为空")
    private Integer styleId;
    private String styleName;
    @NotNull(message = "需求保证金不得为空")
    private BigDecimal budget;
    private Integer budgetStatus;
    private Short auditStatus;
    @NotNull(message = "需求分类不得为空")
    private Integer classId;
}

需要验证的参数添加 @Valid 注解随后紧跟一个 BindingResult 用于处理错误

必须在验证的参数后添加一个 BindingResult 不然 Spring 会直接返回 400 错误

public String add(@Valid DemandForm demandForm, BindingResult result) {
    if(result.hasErrors()){
        return "验证错误: " + result.getAllErrors().get(0).getDefaultMessage()
    }
}

验证注解

@org.hibernate.validator.constraints.Email
- 限制必须为一个邮箱
@org.hibernate.validator.constraints.Length(value)
- 限制必须为一个指定value长度的字符串
@org.hibernate.validator.constraints.NotBlank
- 限制必须为一个不为空的字符串
@org.hibernate.validator.constraints.NotEmpty
- 限制必须为一个不为空的集合
@org.hibernate.validator.constraints.Range(min, max)
- 限制必须为一个字符串或数字在指定的范围内
@org.hibernate.validator.constraints.SafeHtml
- 限制必须为一个安全的HTML

@org.hibernate.validator.constraints.ScriptAssert(script, lang)

当前注解标记于Class上

使用指定的脚本引擎验证当前对象的数据

_this 代表当前类

@ScriptAssert(lang = "javascript", script = "_this.startDate.before(_this.endDate)")
public class CalendarEvent {
    private Date startDate;
    private Date endDate;
}

@org.hibernate.validator.constraints.URL
- 限制必须为一个URL地址
@javax.validation.constraints.DecimalMax(value)
- 限制必须为一个不大于value的数字
@javax.validation.constraints.DecimalMin(value)
- 限制必须为一个不小于value的数字
@javax.validation.constraints.Digits(integer, fraction)
- 限制必须为一个小数且整数部分的位数不能超过integer 小数部分的位数不能超过fraction
@javax.validation.constraints.Future
- 限制必须是一个将来的日期
@javax.validation.constraints.Past
- 限制必须是一个过去的日期
@javax.validation.constraints.Max(value)
- 限制必须为一个不大于value的数字
@javax.validation.constraints.Min(value)
- 限制必须为一个不小于value的数字
@javax.validation.constraints.NotNull
- 限制必须不为Null
@javax.validation.constraints.Null
- 限制只能为Null
@javax.validation.constraints.Pattern(regexp = "^(.*)$")
- 限制必须符合指定的正则表达式
@javax.validation.constraints.Size(max, min)
- 限制字符长度必须在min到max之间

参数解析

SpringBoot自带的参数解析

创建一个 BeanKit

package com.sixi.ktpd.kits;

import ...;

@Component
public class BeanKit implements ApplicationContextAware {

    private static ApplicationContext context;

    private BeanKit() {}

    public static ApplicationContext getApplicationContext() {
        return context;
    }

    public static <T> T get(String name) {
        return (T) context.getBean(name);
    }

    public static <T> T getOfType(Class<T> clazz) {
        return context.getBean(clazz);
    }

    public static <T> Collection<T> getListOfType(Class<T> clazz) {
        return context.getBeansOfType(clazz).values();
    }

    @Override
    public void setApplicationContext(ApplicationContext context) {
        this.context = context;
    }
}

在继承 WebMvcConfigurerAdapter 的配置文件内重写这个方法

package pw.yumc.demo.config;
import ...;
/**
* Created with IntelliJ IDEA
*
* @author 喵♂呜
* Created on 2017/5/27 13:50.
*/
@Configuration
public class Configurer extends WebMvcConfigurerAdapter {
    /**
    * 自动扫描相关组件并且注册
    */
    @Override
    public void addFormatters(FormatterRegistry registry) {
        for (Converter<?, ?> converter : BeanKit.getListOfType(Converter.class)) {
            registry.addConverter(converter);
        }
        for (GenericConverter converter : BeanKit.getListOfType(GenericConverter.class)) {
            registry.addConverter(converter);
        }
        for (Formatter<?> formatter : BeanKit.getListOfType(Formatter.class)) {
            registry.addFormatter(formatter);
        }
    }
}

自定义参数解析

由于需求中经常用到JSON传递数据每次都需要手动解析一次

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2
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public Map submit(HttpServletRequest request){
    JSON.parseObject(request.getParameter("json"))
}

Spring 支持自定义参数解析的首先创建一个类实现 org.springframework.web.method.support.HandlerMethodArgumentResolver 接口

package pw.yumc.demo.resolver.argument;
import ...;
/**
* Created with IntelliJ IDEA
*
* @author 喵♂呜
* Created on 2017/6/8 13:50.
*/
public class JSONArgumentResolver implements HandlerMethodArgumentResolver {
    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        Class<?> paramType = parameter.getParameterType();
        return JSONObject.class.isAssignableFrom(paramType) || JSONArray.class.isAssignableFrom(paramType);
    }
    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory)throws Exception {
        Class<?> paramType = parameter.getParameterType();
        String json = webRequest.getParameter(parameter.getParameterName());
        if (JSONObject.class.isAssignableFrom(paramType)) {
            return JSON.parseObject(json);
        } else if (JSONArray.class.isAssignableFrom(paramType)) {
            return JSON.parseArray(json);
        } else {
            Method method = parameter.getMethod();
            throw new UnsupportedOperationException("Unknown parameter type: " + paramType + " in method: " + method);
        }
    }
}

在 Spring-Boot 配置类里添加这个解析器

package pw.yumc.demo.config;
import ...;
/**
* Created with IntelliJ IDEA
*
* @author 喵♂呜
* Created on 2017/5/27 13:50.
*/
@Configuration
public class Configurer extends WebMvcConfigurerAdapter {
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
        argumentResolvers.add(new JSONArgumentResolver());
    }
}

最后在方法上就可以直接使用了

package pw.yumc.demo.config;
import ...;
/**
* Created with IntelliJ IDEA
*
* @author 喵♂呜
* Created on 2017/5/27 13:50.
*/
@RestController
@RequestMapping
public class Controller {
    @RequestMapping("/submit")
    public Map submit(JSONObject json){
    }
}

转换 Json 到实体类

在SpringBoot中配置消息转换器即可转换Json为实体类

创建一个配置文件继承于 WebMvcConfigurerAdapter (如果有直接覆盖方法即可)

WebMvcConfig.java

package pw.yumc.spring.core.config;

import ...;

/**
 * Created with IntelliJ IDEA
 *
 * @author 喵♂呜
 * Created on 2017/12/20 16:01.
 */
@Configuration
public class CoreConfig extends WebMvcConfigurerAdapter {
    /**
     * 消息类型转换
     */
    @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(new StringHttpMessageConverter(Charset.forName("UTF-8")));
        //1.需要定义一个convert转换消息的对象;
        FastJsonHttpMessageConverter fastJsonHttpMessageConverter = new FastJsonHttpMessageConverter();
        //2:添加fastJson的配置信息;
        FastJsonConfig fastJsonConfig = new FastJsonConfig();
        fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);
        ////3处理中文乱码问题
        //List<MediaType> fastMediaTypes = new ArrayList<>();
        //fastMediaTypes.add(MediaType.APPLICATION_JSON);
        //fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);
        //fastJsonHttpMessageConverter.setSupportedMediaTypes(fastMediaTypes);
        //4.在convert中添加配置信息.
        fastJsonHttpMessageConverter.setFastJsonConfig(fastJsonConfig);
        converters.add(fastJsonHttpMessageConverter);
    }
}

创建两个简单的实体类

Order.java

package pw.yumc.web.open.domain.entity;

import ...;

/**
 * Created with IntelliJ IDEA
 *
 * @author 喵♂呜
 * Created on 2017/12/20 14:40.
 */
@Data
public class Order {
    private Integer id;
    private Integer userId;
    private BigDecimal amount;
    List<Product> products;
}

Product.java

package pw.yumc.web.open.domain.entity;

import ...;

/**
 * Created with IntelliJ IDEA
 *
 * @author 喵♂呜
 * Created on 2017/12/20 14:41.
 */
@Data
public class Product {
    private Integer id;
    private String name;
    private BigDecimal price;
}

创建一个测试控制器

TestController.java

package pw.yumc.web.open.controller;

import ...;
/**
 * Created with IntelliJ IDEA
 *
 * @author 喵♂呜
 * Created on 2017/12/20 10:42.
 */
@RestController
@RequestMapping("/test")
public class TestController {
    @PostMapping("/order")
    public Order order(@RequestBody Order order) {
        return order;
    }
}

使用CURL测试请求

测试命令

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curl -sX POST http://127.0.0.1:8080/test/order \
-H 'Content-Type: application/json' \
-d '{	"id":111,"userId":1,"amount":100,"products":[{"id":123,"name":"testproduct","price":23}]}'

测试结果

$ curl -sX POST http://172.30.34.3:1221/test/order \
>   -H 'Content-Type: application/json' \
>   -d '{"id":111,"userId":1,"amount":100,"products":[{"id":123,"name":"testproduct","price":23}]}'
{
  "amount":100,
  "id":111,
  "products":[
    {
       "id":123,
       "name":"testproduct",
       "price":23
    }
  ],
  "userId":1
}

异常处理

全局处理异常

新建一个类 GlobeExceptionHandler 继承 ResponseEntityExceptionHandler 添加 @ControllerAdvice 注解

@ControllerAdvice
public class GlobeExceptionHandler extends ResponseEntityExceptionHandler {
    @ExceptionHandler(Throwable.class)
    @ResponseBody
    public String handleControllerException(Throwable ex) {
        // 异常逻辑处理
        ...
        // 这里的返回值和控制器用法一样
        return "后台发生异常 " + ex.getClass().getName() + ": " + ex.getMessage();
    }
}

404异常统一处理

默认情况下 SpringBoot 是不会抛出 404 的异常的
首先设置 DispatcherServlet 分发器的 throwExceptionIfNoHandlerFound 为 true 相关代码如下

代码位于: org.springframework.web.servlet.DispatcherServlet#noHandlerFound

/**
* No handler found -> set appropriate HTTP response status.
* @param request current HTTP request
* @param response current HTTP response
* @throws Exception if preparing the response failed
*/
protected void noHandlerFound(HttpServletRequest request, HttpServletResponse response) throws Exception {
  if (pageNotFoundLogger.isWarnEnabled()) {
    pageNotFoundLogger.warn("No mapping found for HTTP request with URI [" + getRequestUri(request) +
        "] in DispatcherServlet with name '" + getServletName() + "'");
  }
  if (this.throwExceptionIfNoHandlerFound) {
    throw new NoHandlerFoundException(request.getMethod(), getRequestUri(request),
        new ServletServerHttpRequest(request).getHeaders());
  }
  else {
    response.sendError(HttpServletResponse.SC_NOT_FOUND);
  }
}

可以看到设置 throwExceptionIfNoHandlerFound 为 true 之后 Spring 会在找不到处理时抛出异常
新建全局异常拦截类参见全局处理异常

重写 handleNoHandlerFoundException 父类方法中的 handleExceptionInternal 方法的第二个参数

package pw.yumc.demo.config;

import ...;
@ControllerAdvice
public class GlobeExceptionHandler extends ResponseEntityExceptionHandler {
    省略部分代码...;
    @Override
    protected ResponseEntity<Object> handleNoHandlerFoundException(NoHandlerFoundException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
        HttpServletRequest req = ((ServletWebRequest) request).getNativeRequest(HttpServletRequest.class);
        Map<String, Object> map = new HashMap<>();
        map.add("status", 404);
        map.add("msg", "路径未找到!");
        map.add("path", req.getRequestURI());
        map.add("method", req.getMethod());
        map.add("time", System.currentTimeMillis());
        return handleExceptionInternal(ex, map, headers, status, request);
    }
}

常见问题解决

POST接口提示 415 的问题

在开发微信支付的时候遇到一个问题微信回调回来的数据接口提示 415(Unsupported Media Type) 错误

当时的接口是这样写的

@RequestMapping
public String index(@RequestBody(required = false) byte[] body) {
    if (body == null) {
        return fail("数据为空!");
    }
    String notify = new String(body, "UTF-8");
    log.info("收到微信回调通知: {}", notify);
}

几经百度发现是方法内的参数会被 Spring 解析但是微信传过来的又是 XML 而且没有提供 Content-Type 所以不支持

改成直接用流解析就行了

@RequestMapping
public String index(HttpServletRequest request) {
      String notify = StreamUtils.copyToString(request.getInputStream(), Charset.forName("UTF-8"));
      log.info("收到微信回调通知: {}", notify);
}