谷粒学院-分页查询、条件查询带分页、添加、修改

ZHOU_VIP

已于 2022-03-20 18:26:36 修改

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分类专栏： GuLi学院文章标签： java

于 2022-03-20 18:26:11 首次发布

本文链接：https://blog.youkuaiyun.com/ZHOU_VIP/article/details/123608256

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本文档详细介绍了如何在Spring Boot项目中利用MyBatis分页插件PaginationInterceptor实现讲师的分页查询。包括在配置文件中启用插件，创建分页查询的Controller方法，以及条件查询带分页的方法。同时，讲解了如何处理讲师的添加和更新操作，包括自动填充创建和修改时间，并展示了在Swagger中进行接口测试的过程及遇到的问题和解决方案。

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讲师分页查询

注意：也可以使用MyBatis分页插件PageHelper，这里不用

https://blog.youkuaiyun.com/ZHOU_VIP/article/details/121773800

1、EduConfig中配置分页插件

//分页插件
@Bean
public PaginationInterceptor paginationInterceptor(){
       return new PaginationInterceptor();
}

2、分页Controller方法

EduTeacherController中添加分页方法

//分页查询
//current 当前第几页
//limit   每页显示几条数据
@ApiOperation(value = "分页讲师列表")
@GetMapping("pageTeacher/{current}/{limit}")
public R pageListTeacher(
        @ApiParam(name = "current", value = "当前页码", required = true)
        @PathVariable Long current,
        @ApiParam(name = "limit", value = "每页记录数", required = true)
        @PathVariable Long limit){
    //创page对象
    Page<EduTeacher> pageTeacher = new Page<>(current,limit);
    //调用方法实现分页
    teacherService.page(pageTeacher,null);
    long total = pageTeacher.getTotal();//总记录数
    List<EduTeacher> records = pageTeacher.getRecords();//数据list集合
    return R.ok().data("total",total).data("rows",records);
}

也可以新建个HashMap

3、Swagger中测试

讲师条件查询带分页

根据讲师名称name，讲师头衔level、讲师入驻时间gmt_create（时间段）查询

1、创建查询对象

创建com.nanjing.eduservice.entiy.vo包，创建TeacherQuery类查询对象

package com.nanjing.eduservice.entity.vo;

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

/**
 * @author yimo
 * @version 1.0
 * @date 2022/3/20 10:48
 */
@ApiModel(value = "Teacher查询对象", description = "讲师查询对象封装")
@Data
public class TeacherQuery {
    @ApiModelProperty(value = "教师名称,模糊查询")
    private String name;

    @ApiModelProperty(value = "头衔 1高级讲师 2首席讲师")
    private Integer level;

    @ApiModelProperty(value = "查询开始时间", example = "2019-01-01 10:10:10")
    private String begin;//注意，这里使用的是String类型，前端传过来的数据无需进行类型转换

    @ApiModelProperty(value = "查询结束时间", example = "2019-12-01 10:10:10")
    private String end;

}

2、EduTeacherController中增加

@RequestBody：请求方式必须是post方式

//条件查询带分页方法
@ApiOperation(value = "条件查询带分页讲师列表")
@PostMapping("pageTeacherCondition/{current}/{limit}")
public R pageTeacherCondition(
        @ApiParam(name = "current", value = "当前页码", required = true)
        @PathVariable Long current,
        @ApiParam(name = "limit", value = "每页记录数", required = true)
        @PathVariable Long limit,
        @RequestBody(required = false) TeacherQuery teacherQuery){
    //创page对象
    Page<EduTeacher> pageTeacher = new Page<>(current,limit);
    //构建条件
    QueryWrapper<EduTeacher> wrapper = new QueryWrapper<>();
    //多条件组合查询
    //类比mybatis学的动态sql
    String name = teacherQuery.getName();
    Integer level = teacherQuery.getLevel();
    String begin = teacherQuery.getBegin();
    String end = teacherQuery.getEnd();
    //判断条件是否为空，如果不为空拼接条件
    /*if (!StringUtils.isEmpty(name)){
        wrapper.like("name",name);
    }
    if (!StringUtils.isEmpty(level)) {
        wrapper.eq("level",level);
    }
    if (!StringUtils.isEmpty(begin)){
        wrapper.ge("gmt_create",begin);
    }
    if (!StringUtils.isEmpty(end)){
        wrapper.le("gmt_create",end);
    }*/
    //自Spring5.3版本起，isEmpty(Object)已建议弃用，使用hasLength(String)或hasText(String)替代
    if (StringUtils.hasText(name)){
        wrapper.like("name",name);
    }
    //注意String.valueOf(level)会把null转换为值是“null”这四个字母，所以StringUtils.hasText(String.valueOf(level))判断为true
    /*public static String valueOf(Object obj) {
        return (obj == null) ? "null" : obj.toString();
    }*/
    if(null != level){
        if (StringUtils.hasText(String.valueOf(level))) {
            wrapper.eq("level",level);
        }
    }
    if (StringUtils.hasText(begin)){
        wrapper.ge("gmt_create",begin);
    }
    if (StringUtils.hasText(end)){
        wrapper.le("gmt_create",end);
    }
    //调用方法实现分页
    teacherService.page(pageTeacher,wrapper);
    long total = pageTeacher.getTotal();//总记录数
    List<EduTeacher> records = pageTeacher.getRecords();//数据list集合
    return R.ok().data("total",total).data("rows",records);
}

3、Swagger中测试

当前页current填0和1都一样，sql语句都是

Execute SQL：
    SELECT
        id,
        name,
        intro,
        career,
        level,
        avatar,
        sort,
        is_deleted,
        gmt_create,
        gmt_modified 
    FROM
        edu_teacher 
    WHERE
        is_deleted=0 
        AND level = 1 LIMIT 0,10

因为源码上默认设置的current就是从1开始，current为0进来也被赋值成了1

计算分页的时候又把1变成0，limit 0开始

{
  "success": true,
  "code": 20000,
  "message": "成功",
  "data": {
    "total": 3,
    "rows": [
      {
        "id": "1189426437876985857",
        "name": "王二",
        "intro": "高级讲师简介",
        "career": "高级讲师",
        "level": 1,
        "avatar": "https://online-teach-file.oss-cn-beijing.aliyuncs.com/teacher/2019/11/08/e44a2e92-2421-4ea3-bb49-46f2ec96ef88.png",
        "sort": 0,
        "isDeleted": false,
        "gmtCreate": "2019-10-30 14:18:56",
        "gmtModified": "2019-11-12 13:37:35"
      },
      {
        "id": "1189426464967995393",
        "name": "王五",
        "intro": "高级讲师简介",
        "career": "高级讲师",
        "level": 1,
        "avatar": "https://online-teach-file.oss-cn-beijing.aliyuncs.com/teacher/2019/10/30/65423f14-49a9-4092-baf5-6d0ef9686a85.png",
        "sort": 0,
        "isDeleted": false,
        "gmtCreate": "2019-10-30 14:19:02",
        "gmtModified": "2019-11-12 13:37:18"
      },
      {
        "id": "1192249914833055746",
        "name": "李四",
        "intro": "高级讲师简介",
        "career": "高级讲师",
        "level": 1,
        "avatar": "https://online-teach-file.oss-cn-beijing.aliyuncs.com/teacher/2019/11/07/91871e25-fd83-4af6-845f-ea8d471d825d.png",
        "sort": 0,
        "isDeleted": false,
        "gmtCreate": "2019-11-07 09:18:25",
        "gmtModified": "2019-11-12 13:37:01"
      }
    ]
  }
}

自动填充封装

1、在service-base模块中添加

创建包handler，创建自动填充类 MyMetaObjectHandler

package com.nanjing.servicebase.handler;

import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;
import org.apache.ibatis.reflection.MetaObject;
import org.springframework.stereotype.Component;

import java.util.Date;

/**
 * @author yimo
 * @version 1.0
 * @date 2022/3/20 17:32
 */
@Component
public class MyMetaObjectHandler implements MetaObjectHandler {
    @Override
    public void insertFill(MetaObject metaObject) {
        this.setFieldValByName("gmtCreate", new Date(), metaObject);
        this.setFieldValByName("gmtModified", new Date(), metaObject);
    }

    @Override
    public void updateFill(MetaObject metaObject) {
        this.setFieldValByName("gmtModified", new Date(), metaObject);
    }
}

2、在实体类添加自动填充注解

@ApiModelProperty(value = "创建时间")
@TableField(fill= FieldFill.INSERT)
private Date gmtCreate;

@ApiModelProperty(value = "更新时间")
@TableField(fill= FieldFill.INSERT_UPDATE)
private Date gmtModified;

讲师添加功能

1、EduTeacherController类

//添加讲师
@ApiOperation(value = "添加讲师列表")
@PostMapping("addTeacher")
public R addTeacher(@ApiParam(name = "eduTeacher", value = "讲师对象", required = true)
                    @RequestBody EduTeacher eduTeacher){
    boolean save = teacherService.save(eduTeacher);
    if (save){
        return R.ok();
    }else {
        return R.error();
    }
}

2、Swagger中测试

在这里插入图片描述

控制台打印报错信息

Creating a new SqlSession
Registering transaction synchronization for SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@20ada16b]
Releasing transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@20ada16b]
Transaction synchronization deregistering SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@20ada16b]
Transaction synchronization closing SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@20ada16b]
2022-03-20 17:52:26.540 ERROR 21104 --- [nio-8001-exec-5] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.reflection.ReflectionException: Could not set property 'id' of 'class com.nanjing.eduservice.entity.EduTeacher' with value '1505482388258447361' Cause: java.lang.IllegalArgumentException: argument type mismatch] with root cause

java.lang.IllegalArgumentException: argument type mismatch
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
	at org.apache.ibatis.reflection.invoker.MethodInvoker.invoke(MethodInvoker.java:41) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.reflection.wrapper.BeanWrapper.setBeanProperty(BeanWrapper.java:180) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.reflection.wrapper.BeanWrapper.set(BeanWrapper.java:59) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.reflection.MetaObject.setValue(MetaObject.java:140) ~[mybatis-3.4.6.jar:3.4.6]
	at com.baomidou.mybatisplus.core.MybatisDefaultParameterHandler.populateKeys(MybatisDefaultParameterHandler.java:209) ~[mybatis-plus-core-3.0.5.jar:na]
	at com.baomidou.mybatisplus.core.MybatisDefaultParameterHandler.processBatch(MybatisDefaultParameterHandler.java:147) ~[mybatis-plus-core-3.0.5.jar:na]
	at com.baomidou.mybatisplus.core.MybatisDefaultParameterHandler.<init>(MybatisDefaultParameterHandler.java:59) ~[mybatis-plus-core-3.0.5.jar:na]
	at com.baomidou.mybatisplus.core.MybatisXMLLanguageDriver.createParameterHandler(MybatisXMLLanguageDriver.java:37) ~[mybatis-plus-core-3.0.5.jar:na]
	at org.apache.ibatis.session.Configuration.newParameterHandler(Configuration.java:545) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.executor.statement.BaseStatementHandler.<init>(BaseStatementHandler.java:69) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.executor.statement.PreparedStatementHandler.<init>(PreparedStatementHandler.java:40) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.executor.statement.RoutingStatementHandler.<init>(RoutingStatementHandler.java:46) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.session.Configuration.newStatementHandler(Configuration.java:558) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.executor.SimpleExecutor.doUpdate(SimpleExecutor.java:48) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.executor.BaseExecutor.update(BaseExecutor.java:117) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.executor.CachingExecutor.update(CachingExecutor.java:76) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.session.defaults.DefaultSqlSession.update(DefaultSqlSession.java:198) ~[mybatis-3.4.6.jar:3.4.6]
	at org.apache.ibatis.session.defaults.DefaultSqlSession.insert(DefaultSqlSession.java:185) ~[mybatis-3.4.6.jar:3.4.6]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
	at org.mybatis.spring.SqlSessionTemplate$SqlSessionInterceptor.invoke(SqlSessionTemplate.java:433) ~[mybatis-spring-1.3.2.jar:1.3.2]
	at com.sun.proxy.$Proxy81.insert(Unknown Source) ~[na:na]
	at org.mybatis.spring.SqlSessionTemplate.insert(SqlSessionTemplate.java:278) ~[mybatis-spring-1.3.2.jar:1.3.2]
	at com.baomidou.mybatisplus.core.override.PageMapperMethod.execute(PageMapperMethod.java:68) ~[mybatis-plus-core-3.0.5.jar:na]
	at com.baomidou.mybatisplus.core.override.PageMapperProxy.invoke(PageMapperProxy.java:64) ~[mybatis-plus-core-3.0.5.jar:na]
	at com.sun.proxy.$Proxy87.insert(Unknown Source) ~[na:na]
	at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl.save(ServiceImpl.java:108) ~[mybatis-plus-extension-3.0.5.jar:na]
	at com.baomidou.mybatisplus.extension.service.impl.ServiceImpl$$FastClassBySpringCGLIB$$76535273.invoke(<generated>) ~[mybatis-plus-extension-3.0.5.jar:na]
	at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.16.jar:5.3.16]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:783) ~[spring-aop-5.3.16.jar:5.3.16]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.16.jar:5.3.16]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:753) ~[spring-aop-5.3.16.jar:5.3.16]
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.16.jar:5.3.16]
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.16.jar:5.3.16]
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.16.jar:5.3.16]
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.16.jar:5.3.16]
	at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:753) ~[spring-aop-5.3.16.jar:5.3.16]
	at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:698) ~[spring-aop-5.3.16.jar:5.3.16]
	at com.nanjing.eduservice.service.impl.EduTeacherServiceImpl$$EnhancerBySpringCGLIB$$dd7f3893.save(<generated>) ~[classes/:na]
	at com.nanjing.eduservice.controller.EduTeacherController.addTeacher(EduTeacherController.java:141) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_241]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_241]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_241]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_241]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.16.jar:5.3.16]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:681) ~[tomcat-embed-core-9.0.58.jar:4.0.FR]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.16.jar:5.3.16]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.58.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.16.jar:5.3.16]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.16.jar:5.3.16]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.16.jar:5.3.16]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.16.jar:5.3.16]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.16.jar:5.3.16]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.16.jar:5.3.16]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:540) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:359) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:889) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1735) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.58.jar:9.0.58]
	at java.lang.Thread.run(Thread.java:748) [na:1.8.0_241]

原来是Id设置不对

改成：

测试ok：

数据库也有新增记录

讲师修改功能

1、EduTeacherController类

//根据id查询讲师，查询回显
@ApiOperation(value = "根据id查询讲师")
@GetMapping("getTeacher/{id}")
public R getTeacher(@ApiParam(name = "id", value = "讲师ID", required = true)
                    @PathVariable String id){
    EduTeacher eduTeacher = teacherService.getById(id);
    return R.ok().data("teacher",eduTeacher);
}


//更新讲师
@ApiOperation(value = "更新讲师")
@PostMapping("updateTeacher")
public R updateTeacher(@ApiParam(name = "eduTeacher", value = "讲师对象", required = true)
                       @RequestBody EduTeacher eduTeacher){
    boolean flag = teacherService.updateById(eduTeacher);
    if (flag){
        return R.ok();
    }else {
        return R.error();
    }
}

还有一种写法，用PUT方式提交，需要teacher.setId(id)设置值