SpringBoot整合SpringMVC、持久层技术MyBatis、连接mysql数据库技术
1、通过使用SpringBoot、SpringMVC、MyBatis整合，实现一个对数据库中的数据表的增加、修改、删除、查询操作。
首先说明一下，这里使用的是Springboot2.2.6.RELEASE版本，由于Springboot迭代很快，所以要注意版本问题。
在pom文件中新增依赖包，如下所示：
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 3 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> 4 <modelVersion>4.0.0</modelVersion> 5 <parent> 6 <groupId>org.springframework.boot</groupId> 7 <artifactId>spring-boot-starter-parent</artifactId> 8 <version>2.2.6.RELEASE</version> 9 <relativePath/> <!-- lookup parent from repository --> 10 </parent> 11 <groupId>com.bie</groupId> 12 <artifactId>springboot-hello</artifactId> 13 <version>0.0.1-SNAPSHOT</version> 14 <name>springboot-hello</name> 15 <description>Demo project for Spring Boot</description> 16 17 <properties> 18 <java.version>1.8</java.version> 19 </properties> 20 21 <dependencies> 22 <dependency> 23 <groupId>org.springframework.boot</groupId> 24 <artifactId>spring-boot-starter-web</artifactId> 25 </dependency> 26 <dependency> 27 <groupId>org.springframework.boot</groupId> 28 <artifactId>spring-boot-starter-test</artifactId> 29 <scope>test</scope> 30 <exclusions> 31 <exclusion> 32 <groupId>org.junit.vintage</groupId> 33 <artifactId>junit-vintage-engine</artifactId> 34 </exclusion> 35 </exclusions> 36 </dependency> 37 <!-- thymeleaf的启动器 --> 38 <dependency> 39 <groupId>org.springframework.boot</groupId> 40 <artifactId>spring-boot-starter-thymeleaf</artifactId> 41 </dependency> 42 <!-- mybatis的启动器 --> 43 <dependency> 44 <groupId>org.mybatis.spring.boot</groupId> 45 <artifactId>mybatis-spring-boot-starter</artifactId> 46 <version>2.1.1</version> 47 </dependency> 48 <!-- mysql数据库驱动的依赖包 --> 49 <dependency> 50 <groupId>mysql</groupId> 51 <artifactId>mysql-connector-java</artifactId> 52 </dependency> 53 <!-- druid数据库连接池 --> 54 <dependency> 55 <groupId>com.alibaba</groupId> 56 <artifactId>druid</artifactId> 57 <version>1.1.10</version> 58 </dependency> 59 </dependencies> 60 61 <build> 62 <plugins> 63 <plugin> 64 <groupId>org.springframework.boot</groupId> 65 <artifactId>spring-boot-maven-plugin</artifactId> 66 </plugin> 67 </plugins> 68 </build> 69 70 </project>
配置application.properties全局配置文件。
1 # 配置端口号8080,默认都是8080 2 server.port=8080 3 server.address=127.0.0.1 4 5 # 数据库驱动,Springboot2.2.6.RELEASE版本 6 spring.datasource.driver-class-name=com.mysql.jdbc.Driver 7 # 数据库链接URL,Springboot2.2.6.RELEASE版本 8 spring.datasource.url=jdbc:mysql://localhost:3306/biehl 9 # 数据库账号,Springboot2.2.6.RELEASE版本 10 spring.datasource.username=root 11 # 数据库密码,Springboot2.2.6.RELEASE版本 12 spring.datasource.password=123456 13 14 # 配置druid数据库连接池,数据源的类型 15 spring.datasource.type=com.alibaba.druid.pool.DruidDataSource 16 17 # 配置mybatis访问实体类的别名,起别名 18 mybatis.type-aliases-package=com.bie.springboothello.po
数据库表设计，简单的创建一个users数据表。
1 /* 2 Navicat Premium Data Transfer 3 4 Source Server : localhost 5 Source Server Type : MySQL 6 Source Server Version : 50724 7 Source Host : localhost:3306 8 Source Schema : biehl 9 10 Target Server Type : MySQL 11 Target Server Version : 50724 12 File Encoding : 65001 13 14 Date: 11/05/2020 12:13:21 15 */ 16 17 SET NAMES utf8mb4; 18 SET FOREIGN_KEY_CHECKS = 0; 19 20 -- ---------------------------- 21 -- Table structure for users 22 -- ---------------------------- 23 DROP TABLE IF EXISTS `users`; 24 CREATE TABLE `users` ( 25 `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '用户编号', 26 `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci DEFAULT NULL COMMENT '用户账号', 27 `age` int(11) DEFAULT NULL COMMENT '用户年龄', 28 PRIMARY KEY (`id`) USING BTREE 29 ) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '用户表' ROW_FORMAT = Dynamic; 30 31 SET FOREIGN_KEY_CHECKS = 1;
创建实体类Users。
1 package com.bie.springboothello.po; 2 3 public class Users { 4 5 private int id; 6 private String name; 7 private int age; 8 9 public int getId() { 10 return id; 11 } 12 13 public void setId(int id) { 14 this.id = id; 15 } 16 17 public String getName() { 18 return name; 19 } 20 21 public void setName(String name) { 22 this.name = name; 23 } 24 25 public int getAge() { 26 return age; 27 } 28 29 public void setAge(int age) { 30 this.age = age; 31 } 32 33 @Override 34 public String toString() { 35 return "Users{" + 36 "id=" + id + 37 ", name='" + name + '\'' + 38 ", age=" + age + 39 '}'; 40 } 41 42 public Users(int id, String name, int age) { 43 this.id = id; 44 this.name = name; 45 this.age = age; 46 } 47 }
创建 mapper 接口以及映射配置文件。
1 package com.bie.springboothello.mapper; 2 3 import com.bie.springboothello.po.Users; 4 import org.springframework.stereotype.Repository; 5 6 import java.util.List; 7 8 /** 9 * 10 */ 11 @Repository // 在启动类里面，如果开启@MapperScan注解。 12 public interface UsersMapper { 13 14 /** 15 * 插入用户信息 16 * 17 * @param users 18 */ 19 public void insertUser(Users users); 20 21 /** 22 * 查询所有的用户信息 23 * 24 * @return 25 */ 26 public List<Users> selectUsersAll(); 27 28 /** 29 * 根据用户的编号进行查询 30 * 31 * @param id 32 * @return 33 */ 34 public Users selectUsersById(Integer id); 35 36 37 /** 38 * 修改用户信息 39 * 40 * @param users 41 */ 42 public void updateUser(Users users); 43 44 /** 45 * 根据用户的编号进行删除操作 46 * 47 * @param id 48 */ 49 public void deleteUserById(Integer id); 50 }
映射配置文件，如下所示，出现的问题在后面进行描述。
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE mapper 3 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 5 <!-- namespace的值必须和Mapper的接口名称相同 --> 6 <mapper namespace="com.bie.springboothello.mapper.UsersMapper"> 7 8 <!-- id必须和UsersMapper接口里面的方法名称相同 --> 9 <!-- 由于在application.properties配置了mybatis.type-aliases-package别名，所以这里直接使用实体类名称即可 --> 10 11 <!-- 插入用户信息 --> 12 <insert id="insertUser" parameterType="users"> 13 insert into users(name,age) values(#{name},#{age}) 14 </insert> 15 16 <!-- 查询所有的用户信息 --> 17 <select id="selectUsersAll" resultType="users"> 18 select id,name,age from users 19 </select> 20 21 <!-- 根据用户的编号进行查询 --> 22 <select id="selectUsersById" resultType="users"> 23 select id,name,age from users where id = #{value} 24 </select> 25 26 <!-- 修改用户信息 --> 27 <update id="updateUser" parameterType="users"> 28 update users set name=#{name} ,age=#{age} where id=#{id} 29 </update> 30 31 <!-- 根据用户的编号进行删除操作 --> 32 <delete id="deleteUserById"> 33 delete from users where id = #{value} 34 </delete> 35 </mapper>
创建业务层接口和业务层接口实现类。
1 package com.bie.springboothello.service; 2 3 import com.bie.springboothello.po.Users; 4 5 import java.util.List; 6 7 /** 8 * 9 */ 10 public interface UsersService { 11 12 /** 13 * 插入用户信息 14 * 15 * @param users 16 */ 17 public void addUser(Users users); 18 19 /** 20 * 查询所有的用户信息 21 * 22 * @return 23 */ 24 public List<Users> findUserAll(); 25 26 /** 27 * 根据用户的编号进行查询 28 * 29 * @param id 30 * @return 31 */ 32 public Users findUserById(Integer id); 33 34 /** 35 * 修改用户信息 36 * 37 * @param users 38 */ 39 public void updateUser(Users users); 40 41 /** 42 * 根据用户的编号进行删除操作 43 * 44 * @param id 45 */ 46 public void deleteUserById(Integer id); 47 }
业务层接口实现类。
1 package com.bie.springboothello.service.impl; 2 3 import com.bie.springboothello.mapper.UsersMapper; 4 import com.bie.springboothello.po.Users; 5 import com.bie.springboothello.service.UsersService; 6 import org.springframework.beans.factory.annotation.Autowired; 7 import org.springframework.stereotype.Service; 8 import org.springframework.transaction.annotation.Transactional; 9 10 import java.util.List; 11 12 @Service // 注入到Spring的bean容器中 13 @Transactional // 开启事务,该类下的所有方法都受事务控制 14 public class UsersServiceImpl implements UsersService { 15 16 @Autowired // 依赖注入 17 private UsersMapper usersMapper; 18 19 @Override 20 public void addUser(Users users) { 21 this.usersMapper.insertUser(users); 22 } 23 24 @Override 25 public List<Users> findUserAll() { 26 return this.usersMapper.selectUsersAll(); 27 } 28 29 @Override 30 public Users findUserById(Integer id) { 31 return this.usersMapper.selectUsersById(id); 32 } 33 34 @Override 35 public void updateUser(Users users) { 36 this.usersMapper.updateUser(users); 37 } 38 39 @Override 40 public void deleteUserById(Integer id) { 41 this.usersMapper.deleteUserById(id); 42 } 43 44 }
创建控制层。
1 package com.bie.springboothello.controller; 2 3 import com.bie.springboothello.po.Users; 4 import com.bie.springboothello.service.UsersService; 5 import org.springframework.beans.factory.annotation.Autowired; 6 import org.springframework.stereotype.Controller; 7 import org.springframework.ui.Model; 8 import org.springframework.web.bind.annotation.PathVariable; 9 import org.springframework.web.bind.annotation.RequestMapping; 10 import org.springframework.web.bind.annotation.ResponseBody; 11 12 import java.util.List; 13 14 @Controller 15 @RequestMapping(value = "/users") 16 public class UsersController { 17 18 @Autowired 19 private UsersService usersService; 20 21 @RequestMapping(value = "/hello") 22 @ResponseBody 23 public String showUser(Model model) { 24 return "hello"; 25 } 26 27 /** 28 * 页面跳转 29 * <p> 30 * <p> 31 * thymeleaf框架，模板级的视图层技术，需要放到classpath的根目录下，也就是src/main/resources下面的一个包叫做templates的目录下面 32 * 33 * <p> 34 * <p> 35 * 由于templates目录是安全的，不允许直接被外界访问的，所以将视图放到这里面之后，必须有Controller里面的方法 36 * 帮助做页面的跳转，此方法的作用就是做页面的跳转。 37 * 38 * @param page 39 * @return 40 */ 41 @RequestMapping(value = "/{page}") 42 public String showPage(@PathVariable String page) { 43 System.out.println("============================================" + page); 44 return page; 45 } 46 47 /** 48 * 添加用户信息 49 * 50 * @param users 51 * @return 52 */ 53 @RequestMapping(value = "addUser") 54 public String addUser(Users users) { 55 this.usersService.addUser(users); 56 return "redirect:/users/findUserAll"; 57 } 58 59 /** 60 * 查询全部用户 61 * 62 * @param model 63 * @return 64 */ 65 @RequestMapping(value = "findUserAll") 66 public String findUserAll(Model model) { 67 List<Users> list = this.usersService.findUserAll(); 68 model.addAttribute("list", list); 69 return "showUsers"; 70 } 71 72 /** 73 * 根据用户id查询用户信息 74 * 75 * @param id 76 * @param model 77 * @return 78 */ 79 @RequestMapping(value = "findUserById") 80 public String findUserById(Integer id, Model model) { 81 Users user = this.usersService.findUserById(id); 82 model.addAttribute("user", user); 83 return "updateUser"; 84 } 85 86 /** 87 * 更新用户信息 88 * 89 * @param users 90 * @return 91 */ 92 @RequestMapping(value = "editUser") 93 public String editUser(Users users) { 94 this.usersService.updateUser(users); 95 return "redirect:/users/findUserAll"; 96 } 97 98 @RequestMapping(value = "delUser") 99 public String delUser(Integer id) { 100 this.usersService.deleteUserById(id); 101 return "redirect:/users/findUserAll"; 102 103 } 104 }
全局异常处理，如下所示：
1 package com.bie.springboothello.controller; 2 3 4 import org.springframework.context.annotation.Configuration; 5 import org.springframework.web.servlet.HandlerExceptionResolver; 6 import org.springframework.web.servlet.ModelAndView; 7 8 import javax.servlet.http.HttpServletRequest; 9 import javax.servlet.http.HttpServletResponse; 10 11 /** 12 * 通过实现 HandlerExceptionResolver接口做全局异常处理 13 */ 14 @Configuration 15 public class GlobalException implements HandlerExceptionResolver { 16 17 @Override 18 public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) { 19 ModelAndView mv = new ModelAndView(); 20 // 判断不同异常类型，做不同视图跳转 21 if (ex instanceof ArithmeticException) { 22 mv.setViewName("error1"); 23 } 24 if (ex instanceof NullPointerException) { 25 mv.setViewName("error2"); 26 } 27 mv.addObject("error", ex.toString()); 28 return mv; 29 } 30 31 32 }
创建几个页面，如下所示：
1 <!DOCTYPE html> 2 <html xmlns:th="http://www.w3.org/1999/xhtml"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>展示用户数据</title> 6 7 <!-- 最新版本的 Bootstrap 核心 CSS 文件 --> 8 <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css"> 9 <!-- 最新的 Bootstrap 核心 JavaScript 文件 --> 10 <script src="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/js/bootstrap.min.js"></script> 11 <style> 12 tr th { 13 text-align: center; 14 } 15 16 tr td { 17 text-align: center; 18 } 19 20 h1 { 21 text-align: center; 22 } 23 </style> 24 </head> 25 <body> 26 27 <h1>用户列表</h1> 28 <br/> 29 <hr/> 30 <br/><br/> 31 32 <div class="row"> 33 <div class="col-md-2"></div> 34 <div class="col-md-8"> 35 <div style="text-align: left;padding-left:900px;"> 36 <a th:href="@{/users/input}" class="btn btn-success">新增用户</a> 37 </div> 38 <br/> 39 <table class="table table-striped table-hover table-condensed"> 40 <tr> 41 <th>用户ID</th> 42 <th>用户姓名</th> 43 <th>用户年龄</th> 44 <th>操作</th> 45 </tr> 46 <tr th:each="user : ${list}"> 47 <td th:text="${user.id}"></td> 48 <td th:text="${user.name}"></td> 49 <td th:text="${user.age}"></td> 50 <td> 51 <a th:href="@{/users/findUserById(id=${user.id})}" class="btn btn-warning">更新用户</a> 52 <a th:href="@{/users/delUser(id=${user.id})}" class="btn btn-danger">删除用户</a> 53 </td> 54 </tr> 55 </table> 56 </div> 57 <div class="col-md-2"></div> 58 </div> 59 </body> 60 </html>
1 <!DOCTYPE html> 2 <html xmlns:th="http://www.w3.org/1999/xhtml"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>添加用户</title> 6 </head> 7 <body> 8 <h1 style="text-align: center">用户管理~新增用户</h1> 9 <hr/> 10 11 <div style="text-align: center"> 12 <form th:action="@{/users/addUser}" method="post"> 13 用户姓名：<input type="text" name="name"/><br/> 14 用户年龄：<input type="text" name="age"/><br/><br/> 15 <input type="submit" value="确定"/> 16 <input type="reset" value="重置"/><br/> 17 </form> 18 </div> 19 20 </body> 21 </html>
1 <!DOCTYPE html> 2 <html xmlns:th="http://www.w3.org/1999/xhtml"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Insert title here</title> 6 </head> 7 <body> 8 9 <h1 style="text-align: center">用户管理~修改用户</h1> 10 <hr/> 11 12 <div style="text-align: center"> 13 <form th:action="@{/users/editUser}" method="post"> 14 <input type="hidden" name="id" th:field="${user.id}"/> <!-- th:field做数据的回显 --> 15 用户姓名：<input type="text" name="name" th:field="${user.name}"/><br/> 16 用户年龄：<input type="text" name="age" th:field="${user.age}"/><br/> 17 <input type="submit" value="确定"/><br/> 18 </form> 19 </div> 20 </body> 21 </html>
创建启动类，如下所示：
1 package com.bie.springboothello; 2 3 import org.mybatis.spring.annotation.MapperScan; 4 import org.springframework.boot.SpringApplication; 5 import org.springframework.boot.autoconfigure.SpringBootApplication; 6 7 @SpringBootApplication 8 // @MapperScan注解，用户扫描MyBatis的Mapper接口，根据扫描的接口生成代理对象 9 @MapperScan(value = "com.bie.springboothello.mapper") 10 public class SpringbootHelloApplication { 11 12 public static void main(String[] args) { 13 SpringApplication.run(SpringbootHelloApplication.class, args); 14 } 15 16 17 }
运行效果，如下所示：
运行的地址：http://127.0.0.1:8080/users/findUserAll
新增用户的界面。
修改用户的界面。
错误描述一，出现这种问题是由于serverTimezone的问题，在application.properties后面配置一下即可。如下所示：
1 spring.datasource.url=jdbc:mysql://localhost:3306/biehl?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC
出现的错误，如下所示：
1 java.sql.SQLException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 2 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:129) ~[mysql-connector-java-8.0.19.jar:8.0.19] 3 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:97) ~[mysql-connector-java-8.0.19.jar:8.0.19] 4 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:89) ~[mysql-connector-java-8.0.19.jar:8.0.19] 5 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:63) ~[mysql-connector-java-8.0.19.jar:8.0.19] 6 at com.mysql.cj.jdbc.exceptions.SQLError.createSQLException(SQLError.java:73) ~[mysql-connector-java-8.0.19.jar:8.0.19] 7 at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:76) ~[mysql-connector-java-8.0.19.jar:8.0.19] 8 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) ~[mysql-connector-java-8.0.19.jar:8.0.19] 9 at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) ~[mysql-connector-java-8.0.19.jar:8.0.19] 10 at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) ~[mysql-connector-java-8.0.19.jar:8.0.19] 11 at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) ~[mysql-connector-java-8.0.19.jar:8.0.19] 12 at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1558) ~[druid-1.1.10.jar:1.1.10] 13 at com.alibaba.druid.pool.DruidAbstractDataSource.createPhysicalConnection(DruidAbstractDataSource.java:1623) ~[druid-1.1.10.jar:1.1.10] 14 at com.alibaba.druid.pool.DruidDataSource$CreateConnectionThread.run(DruidDataSource.java:2468) ~[druid-1.1.10.jar:1.1.10] 15 Caused by: com.mysql.cj.exceptions.InvalidConnectionAttributeException: The server time zone value '�й���ʱ��' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the 'serverTimezone' configuration property) to use a more specifc time zone value if you want to utilize time zone support. 16 at sun.reflect.GeneratedConstructorAccessor30.newInstance(Unknown Source) ~[na:na] 17 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_191] 18 at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_191] 19 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) ~[mysql-connector-java-8.0.19.jar:8.0.19] 20 at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:85) ~[mysql-connector-java-8.0.19.jar:8.0.19] 21 at com.mysql.cj.util.TimeUtil.getCanonicalTimezone(TimeUtil.java:132) ~[mysql-connector-java-8.0.19.jar:8.0.19] 22 at com.mysql.cj.protocol.a.NativeProtocol.configureTimezone(NativeProtocol.java:2118) ~[mysql-connector-java-8.0.19.jar:8.0.19] 23 at com.mysql.cj.protocol.a.NativeProtocol.initServerSession(NativeProtocol.java:2142) ~[mysql-connector-java-8.0.19.jar:8.0.19] 24 at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1310) ~[mysql-connector-java-8.0.19.jar:8.0.19] 25 at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) ~[mysql-connector-java-8.0.19.jar:8.0.19] 26 at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) ~[mysql-connector-java-8.0.19.jar:8.0.19] 27 ... 6 common frames omitted
错误描述二，出现这个问题是很多啊，百度也有很多的讲解，自己也记录一下吧。由于使用的idea工具，springboot开发，由于UsersMapper.xml所在的位置不同，我的映射文件所在位置，项目结构，如下所示。
在mybatis中dao接口与mapper配置文件在做映射绑定的时候出现问题，简单说，就是接口与xml要么是找不到，要么是找到了却匹配不到。错误如下所示：
1 org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.bie.springboothello.mapper.UsersMapper.insertUser 2 at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:235) ~[mybatis-3.5.3.jar:3.5.3] 3 at org.apache.ibatis.binding.MapperMethod.<init>(MapperMethod.java:53) ~[mybatis-3.5.3.jar:3.5.3] 4 at org.apache.ibatis.binding.MapperProxy.lambda$cachedMapperMethod$0(MapperProxy.java:98) ~[mybatis-3.5.3.jar:3.5.3] 5 at java.util.concurrent.ConcurrentHashMap.computeIfAbsent(ConcurrentHashMap.java:1660) ~[na:1.8.0_191] 6 at org.apache.ibatis.binding.MapperProxy.cachedMapperMethod(MapperProxy.java:97) ~[mybatis-3.5.3.jar:3.5.3] 7 at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:92) ~[mybatis-3.5.3.jar:3.5.3] 8 at com.sun.proxy.$Proxy63.insertUser(Unknown Source) ~[na:na] 9 at com.bie.springboothello.service.impl.UsersServiceImpl.addUser(UsersServiceImpl.java:21) ~[classes/:na] 10 at com.bie.springboothello.service.impl.UsersServiceImpl$$FastClassBySpringCGLIB$$6c792bea.invoke(<generated>) ~[classes/:na] 11 at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.2.5.RELEASE.jar:5.2.5.RELEASE] 12 at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771) ~[spring-aop-5.2.5.RELEASE.jar:5.2.5.RELEASE] 13 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.2.5.RELEASE.jar:5.2.5.RELEASE] 14 at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.2.5.RELEASE.jar:5.2.5.RELEASE] 15 at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:366) ~[spring-tx-5.2.5.RELEASE.jar:5.2.5.RELEASE] 16 at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:118) ~[spring-tx-5.2.5.RELEASE.jar:5.2.5.RELEASE] 17 at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.2.5.RELEASE.jar:5.2.5.RELEASE] 18 at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.2.5.RELEASE.jar:5.2.5.RELEASE] 19 at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:691) ~[spring-aop-5.2.5.RELEASE.jar:5.2.5.RELEASE] 20 at com.bie.springboothello.service.impl.UsersServiceImpl$$EnhancerBySpringCGLIB$$9682ec5a.addUser(<generated>) ~[classes/:na] 21 at com.bie.springboothello.controller.UsersController.addUser(UsersController.java:55) ~[classes/:na] 22 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_191] 23 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_191] 24 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_191] 25 at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_191] 26 at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 27 at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 28 at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 29 at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:879) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 30 at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:793) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 31 at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 32 at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 33 at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 34 at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 35 at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 36 at javax.servlet.http.HttpServlet.service(HttpServlet.java:660) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 37 at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.2.5.RELEASE.jar:5.2.5.RELEASE] 38 at javax.servlet.http.HttpServlet.service(HttpServlet.java:741) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 39 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 40 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 41 at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.33.jar:9.0.33] 42 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 43 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 44 at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 45 at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 46 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 47 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 48 at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 49 at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 50 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 51 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 52 at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 53 at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119) ~[spring-web-5.2.5.RELEASE.jar:5.2.5.RELEASE] 54 at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 55 at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 56 at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202) ~[tomcat-embed-core-9.0.33.jar:9.0.33] 57 at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-9.0.33.jar:9.0.33] 58 at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.33.jar:9.0.33] 59 at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139) [tomcat-embed-core-9.0.33.jar:9.0.33] 60 at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.33.jar:9.0.33] 61 at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) [tomcat-embed-core-9.0.33.jar:9.0.33] 62 at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343) [tomcat-embed-core-9.0.33.jar:9.0.33] 63 at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373) [tomcat-embed-core-9.0.33.jar:9.0.33] 64 at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.33.jar:9.0.33] 65 at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868) [tomcat-embed-core-9.0.33.jar:9.0.33] 66 at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1594) [tomcat-embed-core-9.0.33.jar:9.0.33] 67 at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.33.jar:9.0.33] 68 at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_191] 69 at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_191] 70 at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.33.jar:9.0.33] 71 at java.lang.Thread.run(Thread.java:748) [na:1.8.0_191]
注意：Mapper接口开发需要遵循以下规范：
1）、Mapper.xml文件中的namespace与mapper接口的类路径相同。
2）、Mapper接口方法名和Mapper.xml中定义的每个statement的id相同。
3）、Mapper接口方法的输入参数类型和mapper.xml中定义的每个sql 的parameterType的类型相同。
4）、Mapper接口方法的输出参数类型和mapper.xml中定义的每个sql的resultType的类型相同。
解决映射问题，方法二：除了可以在pom.xml配置resource，把*Mapper.xml文件放到resource文件夹下管理，也可以解决这个问题的。
需要新增，下面配置。
1 # 后台打印sql语句 2 mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl 3 4 # 指定sql映射文件位置,mapper下的所有.xml文件都是映射文件 5 mybatis.mapper-locations=classpath:mapper/*Mapper.xml
项目结构如下所示：
