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Spring Boot 使用mybatis-plus逻辑删除选装件 试想一下我们的系统，我们所有的表都有五个字段，分别是创建者（create_by）、创建时间（create_time）、修改者（update_by）、修改时间（update_time）、删除标志（del_flag）, 同时通过mybatis拦截器，自动注入创建人、创建时间、修改人、修改时间。目前在数据库新增，能自动注入创建人、创建时间，修改时，能自动注入修改人、 修改时间。如果我们调用mybatis-plus提供的删除方法（deleteById），既然是逻辑删除，我们设想的肯定是此时能够自动注入修改人、修改时间，但是，实际测试你会发现，此时sql并没有注入修改人、修改时间。为了解决这个问题，mybatis-plus提供了一个LogicDeleteByIdWithFill的逻辑删除组装件。通过此方法，我们在进行逻辑删除时，便能自动注入修改人、修改时间。继承DefaultSqlInjector/** * Description:官方逻辑删除选装件 * * @author : laughing * DateTime: 2021-06-11 15:21 */ @Component public class MySqlInjector extends DefaultSqlInjector { @Override public List<AbstractMethod> getMethodList(Class<?> mapperClass) { List<AbstractMethod> methodList = super.getMethodList(mapperClass); //2.官方选装件，逻辑删除时，自动填充其他字段（例如逻辑删除时，自动填充删除人是谁，什么时候删除的） methodList.add(new LogicDeleteByIdWithFill()); return methodList; } }配置逻辑删除插件/** * Mybatis-Plus配置 * * @author laughing */ @Configuration @EnableTransactionManagement public class MyBatisPlusConfig { @javax.annotation.Resource private Environment env; static final String DEFAULT_RESOURCE_PATTERN = "**/*.class"; private final Logger logger = LoggerFactory.getLogger(MyBatisPlusConfig.class); @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor(); // 如果用了分页插件注意先 add TenantLineInnerInterceptor 再 add PaginationInnerInterceptor // 用了分页插件必须设置 MybatisConfiguration#useDeprecatedExecutor = false // interceptor.addInnerInterceptor(new PaginationInnerInterceptor()); interceptor.addInnerInterceptor(new TenantLineInnerInterceptor( new TenantLineHandler() { // manager_id = 1088248166370832385 // 获取租户 ID 值表达式，只支持单个 ID 值 @Override public Expression getTenantId() { return new StringValue(SecurityUtils.getOrgCode()); } // 这是 default 方法,默认返回 false 表示所有表都需要拼多租户条件, // 这里设置 role表不需要该条件 @Override public boolean ignoreTable(String tableName) { logger.info("orgCode=======" + SecurityUtils.getOrgCode()); return StringUtils.isEmpty(SecurityUtils.getOrgCode()) || WisdomAgricultureConfig.getFilterTableList().stream().anyMatch(e -> e.equalsIgnoreCase(tableName)); } @Override public String getTenantIdColumn() { return "org_code"; } })); interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); return interceptor; } @Bean public ConfigurationCustomizer configurationCustomizer() { return configuration -> configuration.setUseDeprecatedExecutor(false); } public static String setTypeAliasesPackage(String typeAliasesPackage) { ResourcePatternResolver resolver = (ResourcePatternResolver) new PathMatchingResourcePatternResolver(); MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resolver); List<String> allResult = new ArrayList<String>(); try { for (String aliasesPackage : typeAliasesPackage.split(",")) { List<String> result = new ArrayList<String>(); aliasesPackage = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + ClassUtils.convertClassNameToResourcePath(aliasesPackage.trim()) + "/" + DEFAULT_RESOURCE_PATTERN; Resource[] resources = resolver.getResources(aliasesPackage); if (resources != null && resources.length > 0) { MetadataReader metadataReader = null; for (Resource resource : resources) { if (resource.isReadable()) { metadataReader = metadataReaderFactory.getMetadataReader(resource); try { result.add(Class.forName(metadataReader.getClassMetadata().getClassName()).getPackage().getName()); } catch (ClassNotFoundException e) { e.printStackTrace(); } } } } if (result.size() > 0) { HashSet<String> hashResult = new HashSet<String>(result); allResult.addAll(hashResult); } } if (allResult.size() > 0) { typeAliasesPackage = String.join(",", (String[]) allResult.toArray(new String[0])); } else { throw new RuntimeException("mybatis typeAliasesPackage 路径扫描错误,参数typeAliasesPackage:" + typeAliasesPackage + "未找到任何包"); } } catch (IOException e) { e.printStackTrace(); } return typeAliasesPackage; } public Resource[] resolveMapperLocations(String[] mapperLocations) { ResourcePatternResolver resourceResolver = new PathMatchingResourcePatternResolver(); List<Resource> resources = new ArrayList<Resource>(); if (mapperLocations != null) { for (String mapperLocation : mapperLocations) { try { Resource[] mappers = resourceResolver.getResources(mapperLocation); resources.addAll(Arrays.asList(mappers)); } catch (IOException e) { // ignore } } } return resources.toArray(new Resource[resources.size()]); } @Bean public SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception { String typeAliasesPackage = env.getProperty("mybatis-plus.typeAliasesPackage"); String mapperLocations = env.getProperty("mybatis-plus.mapperLocations"); String configLocation = env.getProperty("mybatis-plus.configLocation"); typeAliasesPackage = setTypeAliasesPackage(typeAliasesPackage); VFS.addImplClass(SpringBootVFS.class); final MybatisSqlSessionFactoryBean sessionFactory = new MybatisSqlSessionFactoryBean(); sessionFactory.setDataSource(dataSource); sessionFactory.setTypeAliasesPackage(typeAliasesPackage); sessionFactory.setMapperLocations(resolveMapperLocations(StringUtils.split(mapperLocations, ","))); sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(configLocation)); sessionFactory.setPlugins(mybatisSqlInterceptor(), mybatisPlusInterceptor()); sessionFactory.setGlobalConfig(globalConfig()); return sessionFactory.getObject(); } @Bean public MybatisSqlInterceptor mybatisSqlInterceptor() { MybatisSqlInterceptor mybatisSqlInterceptor = new MybatisSqlInterceptor(); Properties properties = new Properties(); mybatisSqlInterceptor.setProperties(properties); return mybatisSqlInterceptor; } /** * 逻辑删除插件 */ @Bean public GlobalConfig globalConfig() { GlobalConfig globalConfig = new GlobalConfig(); GlobalConfig.DbConfig dbConfig = new GlobalConfig.DbConfig(); dbConfig.setLogicDeleteValue("Y"); dbConfig.setLogicNotDeleteValue("N"); globalConfig.setDbConfig(dbConfig); globalConfig.setSqlInjector(sqlInjector()); return globalConfig; } /** * 自定义Sql注入器 */ @Bean public MySqlInjector sqlInjector() { return new MySqlInjector(); } }扩展BaseMapper/** * Description: * * @author : laughing * DateTime: 2021-06-11 15:23 */ public interface MyBaseMapper<T> extends BaseMapper<T> { /** * 逻辑删除，并且带自动填充 */ int deleteByIdWithFill(T entity); }修改Mapper接口修改Mapper接口，将原来继承BaseMapper改成我们自定义的MyBaseMapper/** * Description:红外测温 * * @author : laughing * DateTime: 2021-05-18 10:28 */ public interface CulturePigTemperatureMapper extends MyBaseMapper<CulturePigTemperature> { /** * 红外测温列表查询 * @param pig 查询条件 * @return 结果 */ List<CulturePigTemperature> selectCulturePigTemperatureList(CulturePig pig); }修改删除方法将原来的删除方法deleteById改成deleteByIdWithFill再次测试，可以看到修改人、修改时间字段能够在逻辑删除方法时自动注入。 -
Spring Boot解决fastjson序列化丢失小数点后零的问题 项目上使用数值类型（金额）时，比如价格，我们可能会将数值格式化成两位小数。比如12.34或者12.00。如果项目上使用FastJson进行序列化，你会发现如果我们金额是整数，比如12.00，FastJson序列化之后，返回到前端的是12而不是12.00。查阅FastJson文档，我们发现，在fastjson 1.2.16版本之后，JSONField支持新的定制化配置serializeUsing，可以单独对某一个类的某个属性定制序列化。实现ObjectSerializer接口第一步，我们实现ObjectSerializer，提供我们自己序列化的规则，如下/** * Description:FastJson金额序列化格式化成两位 * * @author : laughing * DateTime: 2021-06-11 11:49 */ public class Keep2Format implements ObjectSerializer { private DecimalFormat df = new DecimalFormat("0.00"); @Override public void write(JSONSerializer jsonSerializer, Object object, Object fieldName, Type type, int i) throws IOException { jsonSerializer.write(df.format(object)); } }@JSONField注解字段第二步，通过@JSONField设置我们自定义的序列化规则。@JSONField(serializeUsing = Keep2Format.class)再次查看数据，可以发现price字段已经格式化成两位小数。{message type="warning" content="注意：此功能需要fastjson 1.2.16及之后的版本"/}
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Spring Boot Session共享 正常情况下，HttpSession是通过Servlet容器创建并进行管理的。创建成功之后都是保存在内存中的。如果开发者需要对项目进行横向扩展搭建集群，那么可以利用一些硬件或者软件工具来做负载均衡，此时，来自同一个用户的HTTP请求就有可能被分发到不同的实例上去，如何保证各个实例之间Session的同步就成为了一个必须要解决的问题。Spring Boot提供了自动化的Session共享配置，它结合Redis可以非常方便的解决这个问题。使用Redis解决Session共享问题的原理非常简单，就是把原本存储在不同服务器上的Session拿出来放到一个独立的服务器上。添加依赖<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <dependency> <groupId>org.springframework.session</groupId> <artifactId>spring-session-data-redis</artifactId> </dependency>配置redis修改配置文件，增加redis配置spring.redis.database=0 spring.redis.host=localhost spring.redis.port=6379创建controller测试@RestController public class RedidSessionController { @Value("${server.port}") public String port; @PostMapping("/save") public String saveName(String name, HttpSession session) { session.setAttribute("name", name); return "hello," + name + ":" + port; } @PostMapping("/get") public String getName(HttpSession session) { session.getAttribute("name"); return "hello," + session.getAttribute("name") + ":" + port; } }打包jar包通过mvn clean package打包成jar包。分别执行java -jar demo-0.0.1-SNAPSHOT.jar --server.port=8080 java -jar demo-0.0.1-SNAPSHOT.jar --server.port=8081通过8080、8081两个端口运行配置nginx负载均衡主要配置内容如下upstream test.com{ server localhost:8080 weight=1; server localhost:8081 weight=1; } server { listen 80; server_name localhost; #charset koi8-r; #access_log logs/host.access.log main; location / { proxy_pass http://test.com; root html; index index.html index.htm; } } 配置文件中首先配置上游服务器，即两个real server，权重都是1，也就是说，请求平均分配到8080及8081端口。测试我们通过postman，调用save方法，保存session信息。然后再次通过postman，调用get方法，可以看到，系统正确的获取到8080端口保存的session信息。再次打开redis，查看session信息可以看到，session信息正确保存到了我们配置的redis数据库中。
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Spring Boot @WebServlet、@WebFilter、@WebListener的使用 三个注解都必须在启动类增加@ServletComponentScan才能够被扫描到。@WebServlet可用于根据不同条件，重定向请求至不同URL。示例代码@WebServlet(name = "/my") @Slf4j public class MyWebServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) { log.info("进入get方法"); log.info(req.getParameter("name")); doPost(req,resp); } @Override protected void doHead(HttpServletRequest req, HttpServletResponse resp) { log.info("进入get方法"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) { log.info("进入post方法"); log.info(req.getParameter("name")); } @Override protected void doPut(HttpServletRequest req, HttpServletResponse resp) { log.info("进入put方法"); } @Override protected void doDelete(HttpServletRequest req, HttpServletResponse resp) { log.info("进入delete方法"); } @Override protected void doOptions(HttpServletRequest req, HttpServletResponse resp) { log.info("进入option方法"); } @Override public void destroy() { log.info("servlet>>>destroy"); } @Override public void init() { log.info("servlet>>>init"); } } 使用postman分别通过get、post、delete等进行请求http://localhost:8080/my?name=张三，可以查看输出结果@WebFilter可用于拦截/过滤请求，提前对请求的request进行判断处理，在doFilter后过滤器放行，调用实际请求URL路径。示例代码@WebFilter("/my") @Slf4j public class MyWebFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { log.info("filter>>>init"); } @Override public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { log.info("进入doFilter方法"); filterChain.doFilter(servletRequest,servletResponse); } @Override public void destroy() { log.info("filter>>>destroy"); } }再次请求，查看输出结果{message type="error" content="注意看输出顺序"/}@WebListener在spring启动之前监听执行初始化操作，可用于提前加载缓存等。@WebListener @Slf4j public class MyWebListener implements ServletRequestListener { @Override public void requestDestroyed(ServletRequestEvent sre) { log.info("requestDestroyed"); } @Override public void requestInitialized(ServletRequestEvent sre) { log.info("requestInitialized"); } }
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Spring Boot通过ApplicationRunner实现系统启动任务 在Spring Boot通过CommandLineRunner实现系统启动任务中我们介绍了通过CommandLineRunner实现启动任务。但是CommandLineRunner实现的启动任务，我们在传递入口参数时，只能传递基本类型，入法通过键值对的形式传递参数。ApplicationRunner的实现原理跟CommandLineRunner基本类似，我们终点说一下ApplicationRunner的用法。ApplicationRunner实现类中run()方法参数为ApplicationArguments,ApplicationArguments说明如下：通过getNonOptionArgs()获取基本参数，这个与CommandLineRunner的参数是一致的。通过getOptionNames()获取键。通过getOptionValues获取值。演示代码@Component @Order(1) @Slf4j public class MyApplicationRunner implements ApplicationRunner { @Override public void run(ApplicationArguments args) { List<String> nonOptionArgs = args.getNonOptionArgs(); Set<String> optionNames = args.getOptionNames(); List<String> optionValues = args.getOptionValues("name"); log.info("MyApplicationRunner>>>nonOptionArgs>>>" + nonOptionArgs.toString()); log.info("MyApplicationRunner>>>optionNames>>>" + optionNames.toString()); log.info("MyApplicationRunner>>>optionValues>>>" + optionValues.toString()); } }修改入口参数--name代表键，=后面是值，注意是--不是-
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Spring Boot通过CommandLineRunner实现系统启动任务 所谓系统启动任务，是在系统启动时执行的一些操作，一般而言只在系统启动之时执行，并且一般只执行一次。比如加载配置文件、数据库初始化操作等。Spring Boot针对系统启动任务，提供了两种解决方案：一是实现CommandLineRunner接口另一种方式是实现ApplicationRunner接口。本文针对CommandLineRunner方式进行说明。Spring Boot项目在启动时，会遍历所有CommandLineRunner实现类并调用其中的run()方法。如果系统中有多个CommandLineRunner实现类，可以通过@Order()注解指定实现类的调用顺序，数值越小越先执行。{mtitle title="演示代码"/}MyCommandLineRunner1@Component @Order(1) @Slf4j public class MyCommandLineRunner1 implements CommandLineRunner { @Override public void run(String... args) throws Exception { log.info("Runner1>>>" + Arrays.toString(args)); } }MyCommandLineRunner2@Component @Order(1) @Slf4j public class MyCommandLineRunner2 implements CommandLineRunner { @Override public void run(String... args) { log.info("Runner2>>>" + Arrays.toString(args)); } }idea配置入口参数@Order(1)用来描述CommandLineRunner的执行顺序，值越小越先执行。run()方法的参数是系统启动时传入的参数。
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vue-baidu-map通过路书实现轨迹回放 网上实现轨迹回放的代码很多，但是很少有vue实现的。本文通过vue-baidu-map对vue轨迹回放功能进行说明。安装依赖npm install vue-baidu-map --save修改main.jsmain.js增加以下内容，注意ak需要替换成自己的。import BaiduMap from 'vue-baidu-map' Vue.use(BaiduMap, { ak: '替换成自己的ak' })前端页面<template> <div class="app-container"> <el-form :model="queryParams" ref="queryForm" :inline="true"> <el-row> <el-col :span="6"> <el-form-item label="车辆" prop="vehicleLicence"> <el-select filterable v-model="queryParams.vehicleLicence" placeholder="请选择车辆" clearable size="small" style="width: 100%" > <el-option v-for="vehicle in vehicleOptions" :key="vehicle.licence" :label="vehicle.licence" :value="vehicle.licence" /> </el-select> </el-form-item> </el-col> <el-col :span="8"> <el-form-item label="查询时间" prop="dateRange"> <el-date-picker v-model="dateRange" size="small" style="width: 100%" value-format="yyyy-MM-dd HH:mm:ss" type="datetimerange" range-separator="-" start-placeholder="请选择开始时间" end-placeholder="请选择结束时间" :picker-options="pickerOptions" ></el-date-picker> </el-form-item> </el-col> <el-col :span="5"> <el-form-item label="轨迹速度"> <el-slider v-model="speed" style="width: 200px" :step="1"></el-slider> </el-form-item> </el-col> <el-col :span="5"> <el-form-item style="float: right"> <el-button type="cyan" icon="el-icon-search" size="mini" @click="handleQuery">查询</el-button> <el-button icon="el-icon-refresh" size="mini" @click="resetQuery">重置</el-button> </el-form-item> </el-col> </el-row> </el-form> <baidu-map style="height:47.1rem;width:100%" :center="center" :zoom="15" :scroll-wheel-zoom="true"> <bm-polyline :path="path" stroke-color="blue" :stroke-opacity="0.5" :stroke-weight="3" :editing="false" ></bm-polyline> <bm-marker :position="{lng: startMark.lng, lat: startMark.lat}"></bm-marker> <bm-marker :position="{lng: endMark.lng, lat: endMark.lat}"></bm-marker> <bml-lushu @stop="reset" :path="path" :icon="icon" :play="play" :rotation="true" :speed="speed * 10" :infoWindow="true" :content="content" > </bml-lushu> </baidu-map> </div> </template> <script> //百度地图 import BaiduMap from 'vue-baidu-map/components/map/Map.vue' import BmScale from 'vue-baidu-map/components/controls/Scale' import BmNavigation from 'vue-baidu-map/components/controls/Navigation' import BmMarkerClusterer from 'vue-baidu-map/components/extra/MarkerClusterer' import BmMarker from 'vue-baidu-map/components/overlays/Marker' import BmInfoWindow from 'vue-baidu-map/components/overlays/InfoWindow' import { BmlLushu } from 'vue-baidu-map' import drugMarkerIcon from '@/assets/icons/map_marker_check.png' import { selectGpsOrbitList } from '@/api/dmp/industry/gps/orbit' import { listAllVehicle } from '@/api/basic/vehicle' export default { components: { BaiduMap, BmScale, BmNavigation, BmMarkerClusterer, BmMarker, BmInfoWindow, BmlLushu }, props: {}, data() { return { // 查询参数 queryParams: { vehicleLicence: undefined }, // 日期范围 dateRange: [new Date().getFullYear() + '-' + (new Date().getMonth() + 1) + '-' + new Date().getDate() + ' 00:00:00', new Date().getFullYear() + '-' + (new Date().getMonth() + 1) + '-' + new Date().getDate() + ' 23:59:59'], play: false, path: [], center: { lng: 116.984646, lat: 36.659686 }, startMark: {}, endMark: {}, icon: { url: drugMarkerIcon, size: { width: 32, height: 32 }, opts: { anchor: { width: 27, height: 13 } } }, content: undefined, speed: 20, pickerOptions: { disabledDate(time) { return time.getTime() > Date.now() - 8.64e6 } }, vehicleOptions: [] } }, methods: { reset() { this.play = false }, handleSearchComplete(res) { this.path = res.getPlan(0).getRoute(0).getPath() }, handleQuery() { const search = this.addDateRange(this.queryParams, this.dateRange) if (this.queryParams.vehicleLicence === undefined) { this.msgError('请选择车辆') return } if (search.beginTime === undefined || search.beginTime === '' || search.endTime === undefined || search.endTime === '') { this.msgError('请选择查询时间') return } selectGpsOrbitList(this.addDateRange(this.queryParams, this.dateRange)).then(response => { if (response.data.length <= 0) { this.msgError('未查询到该车辆的运行数据') return } let length = response.data.length let middle = -1 if (length % 2 === 0) { middle = length / 2 + 1 } else { middle = (length + 1) / 2 } response.data.forEach(item => { let obj = { lng: item.longitude, lat: item.latitude } this.path.push(obj) }) this.center = this.path[middle] this.startMark = this.path[0] this.endMark = this.path[this.path.length - 1] this.content = this.queryParams.vehicleLicence this.play = true }).catch(error => { }) }, /** 重置按钮操作 */ resetQuery() { this.resetForm('queryForm') this.dateRange = [new Date().getFullYear() + '-' + (new Date().getMonth() + 1) + '-' + new Date().getDate() + ' 00:00:00', new Date().getFullYear() + '-' + (new Date().getMonth() + 1) + '-' + new Date().getDate() + ' 23:59:59'] } }, mounted() { listAllVehicle().then(response => { this.vehicleOptions = response.data }) } } </script> <style> </style> data关键参数说明：play:true或false，为true时，开始播放轨迹。path:数组，格式为[{lng: 116.984646,lat: 36.659686}]center:地图中心点，格式{lng: 116.984646,lat: 36.659686}startMark:轨迹开始经纬度，格式{lng: 116.984646,lat: 36.659686}endMark:轨迹终点经纬度，格式{lng: 116.984646,lat: 36.659686}icon:轨迹图标，如下演示的小车图标content:轨迹显示内容，如下按时的车牌speed:轨迹绘制的速度，这里通过el-slider实现滑动调整速度bm-polyline组件属性说明path:绘制曲线的经纬度数组bml-lushuplay:true或false，为true时，开始播放轨迹。infoWindow:true或false，为true时，显示窗口，及content内容。
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Spring Boot注册拦截器Interceptor Spring MVC提供了AOP风格的拦截器，拥有更加精细的拦截器处理能力。Spring Boot中拦截器的注册更加方便，步骤如下：spring-boot-starter-web创建拦截器，实现HandlerInterceptor配置拦截器，定义配置类进行拦截器的配置增加依赖<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency>实现HandlerInterceptor代码如下：public class MyInterceptor implements HandlerInterceptor { private final Logger logger = LoggerFactory.getLogger(MyInterceptor.class); /** * 方法执行前运行 * 必须返回true，后面的方法才能执行 * @param request * @param response * @param handler * @return * @throws Exception */ @Override public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception { logger.info("我先执行"); return true; } @Override public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception { logger.info("我在controller方法之后执行"); } @Override public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception { logger.info("我最后执行"); } }配置拦截器@Configuration public class MyWebMvcConfig implements WebMvcConfigurer { /** * 拦截器 * * @param registry registry */ @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor(new MyInterceptor()) //配置拦截的路由 .addPathPatterns("/interceptor/**") //配置不拦截的路由 .excludePathPatterns("/demo/**") //配置顺序 .order(1); } }测试定义controller测试我们的拦截器@RestController @RequestMapping("interceptor") public class InterceptorController { private final Logger logger = LoggerFactory.getLogger(InterceptorController.class); @GetMapping("/test") public String testInterceptor(){ logger.info("我是controller方法"); return "success"; } }通过调用http://localhost:8080/interceptor/test查看输出日志。温馨提示拦截器按照preHandle→Controller→postHandle→afterHandle的顺序执行。只有preHandle方法返回true时，后面的方法才会执行。当拦截器链内存在多个拦截器时，postHandle在拦截器链内所有拦截器返回成功时才会调用。当拦截器链内存在多个拦截器时，afterHandle在拦截器链内所有拦截器返回true时才会调用。当拦截器链内存在多个拦截器时，如果第一个拦截器的preHandle方法返回false，则后面的方法都不会执行。调用controller方法时，只要配置了拦截的路由，哪怕前端请求404，仍然会调用preHandle、postHandle及afterHandle的方法。如果我们设置了order，代码如下：/** * 拦截器 * * @param registry registry */ @Override public void addInterceptors(InterceptorRegistry registry) { registry.addInterceptor(new MyInterceptor2()) //配置拦截的路由 .addPathPatterns("/interceptor/**") //配置不拦截的路由 .excludePathPatterns("/demo/**") //配置顺序 .order(200); registry.addInterceptor(new MyInterceptor1()) //配置拦截的路由 .addPathPatterns("/interceptor/**") //配置不拦截的路由 .excludePathPatterns("/demo/**") //配置顺序 .order(300); }
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springboot 通过 DefaultErrorAttributes自定义错误信息 自定义error数据就是对返回的数据进行自定义。Spring Boot返回的Error信息一共有5条，分别是timestamp、status、error、path。在BasicErrorController的errorHtml()方法和error()方法，都是通过getErrorAttributes()方法获取Error信息的，该方法最终会调用DefaultErrorAttributes类的getErrorAttributes()方法，而DefaultErrorAttributes类是在ErrorMvcAutoConfiguration中默认提供的。当系统没有提供 errorAttributes 时才会采 DefaultErrorAttributes，因此自定义错误提示时，只需要自己提供一个ErrorAttributes即可，而DefaultErrorAttributes是ErrorAttributes的子类，因此只需要继承 DefaultErrorAttributes 即可。@Component public class MyErrorAttribute extends DefaultErrorAttributes { @Override public Map<String, Object> getErrorAttributes(WebRequest webRequest, ErrorAttributeOptions options) { Map<String, Object> map = super.getErrorAttributes(webRequest, options); map.put("errorMsg", "出错了"); return map; } }
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SpringBoot 使用Gson 添加依赖需要排除web自带的jackson<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> <exclusions> <exclusion> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>com.google.code.gson</groupId> <artifactId>gson</artifactId> </dependency>增加配置文件@Configuration public class GsonConfig { @Bean @ConditionalOnMissingBean public GsonHttpMessageConverter gsonHttpMessageConverter() { GsonHttpMessageConverter gsonHttpMessageConverter = new GsonHttpMessageConverter(); gsonHttpMessageConverter.setDefaultCharset(StandardCharsets.UTF_8); GsonBuilder gsonBuilder = new GsonBuilder(); //设置日期格式 gsonBuilder.setDateFormat("yyyy-MM-dd"); //设置忽略的字段 gsonBuilder.excludeFieldsWithModifiers(Modifier.PROTECTED); Gson gson = gsonBuilder.create(); gsonHttpMessageConverter.setGson(gson); return gsonHttpMessageConverter; } }增加测试类@Data public class Person { protected Integer age; private String name; private Date birthday; }测试 @GetMapping("test") public Person test() { Person person = new Person(); person.setAge(30); person.setBirthday(new Date()); person.setName("张三"); return person; }
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Spring Boot使用profile 开发者在项目发布之前，一般需要频繁的在开发环境、测试环境及生产环境之间进行切换，这个时候大量的配置需要频繁更改，例如数据库配置、 redis配置、mongodb 配置等。频繁修改带来巨大工作量，Spring对此提供了解决方案（＠Profile注解）, Spring Boot则更进一步提供了更加简洁的解决方案， Spring Boot中约定的不同环境下配置文件名称规则为application-{profile} .properties, profile占位符表示当前环境的名称，具体配置步骤如下。创建配置文件在resources中创建两个配置文件，分别是application-dev.properties和application-prod.properties,分别代表开发环境及正式环境的配置。application-dev.propertiesdev指定端口为8080server.port=8080 server.servlet.context-path=/study server.tomcat.basedir=logapplication-prod.propertiesprod指定端口为8081server.port=8081 server.servlet.context-path=/study server.tomcat.basedir=log在application.properties中配置spring.profiles.active=prod在代码中配置在启动类中设置 public static void main(String[] args) { // SpringApplication.run(DemoApplication.class, args); SpringApplicationBuilder builder = new SpringApplicationBuilder(DemoApplication.class); builder.bannerMode(Banner.Mode.OFF); builder.application().setAdditionalProfiles("prod"); builder.run(args); }在项目启动时配置java -jar demo-0.0.1-SNAPSHOT.jar --spring.profile.active=prod
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java多线程之ThreadLocal类 ThreadLocal是⼀个本地线程副本变量⼯具类。内部是⼀个弱引⽤的Map来维护。这⾥不详细介绍它的原理，⽽是只是介绍它的使⽤，以后有独⽴章节来介绍ThreadLocal类的原理。有些朋友称ThreadLocal为线程本地变量或线程本地存储。严格来说，ThreadLocal类并不属于多线程间的通信，⽽是让每个线程有⾃⼰”独⽴“的变量，线程之间互不影响。它为每个线程都创建⼀个副本，每个线程可以访问⾃⼰内部的副本变量。ThreadLocal类最常⽤的就是set⽅法和get⽅法。package com.company; public class ThreadLocalDemo { static class ThreadA implements Runnable{ private final ThreadLocal<String> threadLocal; public ThreadA(ThreadLocal<String> threadLocal){ this.threadLocal=threadLocal; } @Override public void run() { threadLocal.set("A"); try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("ThreadA输出：" + threadLocal.get()); } } static class ThreadB implements Runnable{ private final ThreadLocal<String> threadLocal; public ThreadB(ThreadLocal<String> threadLocal){ this.threadLocal=threadLocal; } @Override public void run() { threadLocal.set("B"); try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } System.out.println("ThreadB输出：" + threadLocal.get()); } } public static void main(String[] args){ ThreadLocal<String> threadLocal = new ThreadLocal<>(); new Thread(new ThreadA(threadLocal)).start(); new Thread(new ThreadB(threadLocal)).start(); } }
