EasyExcel 是一款由阿里开源的 Excel 处理工具。相较于原生的Apache POI，它可以更优雅、快速地完成 Excel 的读写功能，同时更加地节约内存。即使 EasyExcel 已经很优雅了，但面向 Excel 文档的读写逻辑几乎千篇一律，笔者索性将这些模板化的逻辑抽离出来，该组件已经发布到 maven 中央仓库，感兴趣的朋友可以体验一下。
目前仅支持针对单个 Excel 文档的导入与导出（支持多Sheet），所以由 @RequestExcel 注解修饰的方法参数必须是一个List<List<>>类型，而由 @ResponseExcel 注解修饰的方法返回类型也必须是一个List<List<>>类型，否则将抛出异常。
easyexcel 组件组要自行引入，强制使用 3.3+ 版本。
<dependency> <groupId>io.github.dk900912</groupId> <artifactId>easyexcel-spring-boot-starter</artifactId> <version>1.0.1</version> </dependency>@RestController @RequestMapping(path = "/easyexcel") public class ExcelController { @PostMapping(path = "/v1/upload") public ResponseEntity<String> v1upload( @RequestExcel(sheets = { @Sheet(index = 0, headClazz = User.class, headRowNumber = 1), @Sheet(index = 1, headClazz = User.class, headRowNumber = 1), @Sheet(index = 2, headClazz = User.class, headRowNumber = 1)} ) List<List<User>> users) { return ResponseEntity.ok("OK"); } @PostMapping(path = "/v2/upload") public ResponseEntity<String> v2upload( @RequestExcel(sheets = { @Sheet(index = 0, headClazz = User.class, headRowNumber = 1), @Sheet(index = 1, headClazz = Admin.class, headRowNumber = 1)} ) List<List<Object>> data) { return ResponseEntity.ok("OK"); } @ResponseExcel( name="程序猿", sheets = { @Sheet(name = "sheet-0", headClazz = User.class), @Sheet(name = "sheet-1", headClazz = User.class), @Sheet(name = "sheet-2", headClazz = User.class) }, suffix = ExcelTypeEnum.XLSX) @GetMapping(path = "/v1/export") public List<List<User>> v1export() { List<User> userList = Lists.newArrayList(); for (int i = 0; i < 10000; i++) { User user = User.builder().name("暴风赤红" + (i+1)) .birth(LocalDate.now()).address("江苏省苏州市科技城昆仑山路58号").sex(Sex.MALE) .build(); userList.add(user); } return ImmutableList.of(userList, userList, userList); } @ResponseExcel( name="程序猿", sheets = { @Sheet(name = "sheet-0", headClazz = User.class), @Sheet(name = "sheet-1", headClazz = Admin.class) }, suffix = ExcelTypeEnum.XLS) @GetMapping(path = "/v2/export") public List<List<?>> v2export() { List<User> userList = Lists.newArrayList(); List<Admin> adminList = Lists.newArrayList(); for (int i = 0; i < 10000; i++) { User user = User.builder().name("暴风赤红" + (i+1)) .birth(LocalDate.now()).address("江苏省苏州市科技城昆仑山路58号").sex(Sex.MALE) .build(); userList.add(user); Admin admin = Admin.builder().name("擎天柱" + (i+1)) .birth(LocalDate.now()).address("江苏省苏州市科技城昆仑山路68号").sex(Sex.MALE) .build(); adminList.add(admin); } List<List<?>> responseData = Lists.newArrayList(); responseData.add(userList); responseData.add(adminList); return responseData; } @ResponseExcel(name="templates/tem.xlsx", scene = TEMPLATE) @GetMapping(path = "/v1/template") public void template() {} }一般无需配置
spring.easy-excel.enabled=true spring.easy-excel.converter.media-types[0]=application/octet-stream spring.easy-excel.template.location=classpath: 在非模板导出场景下，导出文件名可以显式指定，也可以不指定，此时会默认使用基于 UUID 的文件名生成策略，如果不满足大家的需求，可以自行实现FileNameGenerator策略接口，然后追加配置项，如下所示：
spring.easy-excel.name.generator=a.b.c.CustomFileNameGenerator同时内置了两个文件名生成器供大家使用，分别是：
- io.github.dk900912.easyexcel.support.TimestampFileNameGenerator
- io.github.dk900912.easyexcel.support.LocalDateTimeFileNameGenerator
依托于 Spring 内部 MethodValidationInterceptor的能力，配合@Validated和@Valid注解即可实现。
@Validated @RestController @RequestMapping(path = "/easyexcel") public class ExcelController { @PostMapping(path = "/v1/upload") public ResponseEntity<String> v1upload( @RequestExcel(sheets = { @Sheet(index = 0, headClazz = User.class, headRowNumber = 1), @Sheet(index = 1, headClazz = User.class, headRowNumber = 1), @Sheet(index = 2, headClazz = User.class, headRowNumber = 1)} ) List<List<@Valid User>> users, @RequestParam("id") String id) { System.out.println(users); System.out.println(id); return ResponseEntity.ok("OK"); } }异常信息如下：
jakarta.validation.ConstraintViolationException: v1upload.users[1].<list element>[0].name: name不能为空, v1upload.users[0].<list element>[0].name: name不能为空 at org.springframework.validation.beanvalidation.MethodValidationInterceptor.invoke(MethodValidationInterceptor.java:138) ~[spring-context-6.0.9.jar:6.0.9] at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:184) ~[spring-aop-6.0.9.jar:6.0.9] at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:750) ~[spring-aop-6.0.9.jar:6.0.9] at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:702) ~[spring-aop-6.0.9.jar:6.0.9] at io.github.xiaotou.easyexcel.ExcelController$$SpringCGLIB$$0.v1upload(<generated>) ~[classes/:na] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77) ~[na:na] at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na] at java.base/java.lang.reflect.Method.invoke(Method.java:568) ~[na:na] at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:207) ~[spring-web-6.0.9.jar:6.0.9] at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:152) ~[spring-web-6.0.9.jar:6.0.9] at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:118) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:884) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1081) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:974) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1011) ~[spring-webmvc-6.0.9.jar:6.0.9] at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:914) ~[spring-webmvc-6.0.9.jar:6.0.9] at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:590) ~[tomcat-embed-core-10.1.8.jar:6.0] at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:885) ~[spring-webmvc-6.0.9.jar:6.0.9] at jakarta.servlet.http.HttpServlet.service(HttpServlet.java:658) ~[tomcat-embed-core-10.1.8.jar:6.0]从上述异常信息来看，出现了两次“name不能为空”，这说明 Jakarta Bean Validation 的实现方（Hibernate）没有开启fail fast机制，可以通过以下方式开启：
spring.easy-excel.validation.fail-fast=false 否则本组件将自动开启fail fast机制，如下：
public class FailFastValidationConfigurationCustomizer implements ValidationConfigurationCustomizer { @Override public void customize(Configuration<?> configuration) { configuration.addProperty("hibernate.validator.fail_fast", "true"); } }