SSM(Spring-Mybatis-SpringMVC)

2023-09-05 06:21

短信预约 -IT技能 免费直播动态提醒

文章目录

1. 介绍

1.1 概念介绍

SSM项目是指基于Spring+SpringMVC+MyBatis框架搭建的Java Web项目。

Spring是负责管理和组织项目的IOC容器和AOP功能
SpringMVC是一个轻量级的MVC框架，用于处理Web请求和响应
MyBatis是一种持久化框架，用于进行数据库操作的ORM框架。

学习笔记：
Spring：https://blog.csdn.net/meini32/article/details/132474555
SpringMVC：https://blog.csdn.net/meini32/article/details/132545058
Mybatis：https://blog.csdn.net/meini32/article/details/132068955
Mybatis商品增删改查案例：https://blog.csdn.net/meini32/article/details/132095237

2 SSM整合框架

关键内容

Spring

SpringConfig

SpringMVC

SpringMvcConfig
ServletConfig

Mybatis

MyBatisConfig
JdbcConfig
jdbc.properties

MyBatis
jdbc.properties

jdbc.driver=com.mysql.jdbc.Driverjdbc.url=jdbc:mysql://localhost:3306/db1jdbc.username=rootjdbc.password=123456

package com.it.config;import javax.sql.DataSource;import com.alibaba.druid.pool.DruidDataSource;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;//jdbcConfigpublic class jdbcConfig {    @Value("${jdbc.driver}")    private String driver;    @Value("${jdbc.url}")    private String url;    @Value("${jdbc.username}")    private String username;    @Value("${jdbc.password}")    private String password;    //数据源    @Bean    public DataSource dataSource(){        DruidDataSource druidDataSource = new DruidDataSource();        druidDataSource.setDriverClassName(driver);        druidDataSource.setUrl(url);        druidDataSource.setUsername(username);        druidDataSource.setPassword(password);        return druidDataSource;    }}-----------------------------------------------------package com.it.config;import org.mybatis.spring.SqlSessionFactoryBean;import org.mybatis.spring.mapper.MapperScannerConfigurer;import org.springframework.context.annotation.Bean;import javax.sql.DataSource;//MyBatisConfigpublic class MybatisConfig {    //创建和管理数据库会话    @Bean    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();        factoryBean.setDataSource(dataSource);        factoryBean.setTypeAliasesPackage("com.it.domain");        return factoryBean;    }    @Bean    //创建并配置MapperScannerConfigurer对象    public MapperScannerConfigurer mapperScannerConfigurer(){        MapperScannerConfigurer mapperScannerConfigurer = new MapperScannerConfigurer();        mapperScannerConfigurer.setBasePackage("com.it.dao");        return mapperScannerConfigurer;    }}

web容器配置类

SpringMVC

SpringMvcConfig
ServletConfig

//ServletConfig@Configurationpublic class ServletConfig extends AbstractAnnotationConfigDispatcherServletInitializer {    @Override    protected Class<?>[] getRootConfigClasses() {        return new Class[]{SpringConfig.class};    }    @Override    protected Class<?>[] getServletConfigClasses() {        return new Class[]{SpringMvcConfig.class};    }    @Override    protected String[] getServletMappings() {        return new String[]{"/"};    }}----------------------------------------------------------------------//SpringMvcConfig@Configuration@ComponentScan("com.it.controller")@EnableWebMvcpublic class SpringMvcConfig {}

Spring

SpringConfig

//整合Spring应用程序，实现对组件和属性的管理和使用@Configuration@ComponentScan({"com.it.service"})@PropertySource("jdbc.properties")@Import({jdbcConfig.class, MybatisConfig.class})public class SpringConfig {}

3. SSM功能模块开发

内容

表与实体类；
dao（接口+自动代理）
service（接口+实现类）
controller

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添加相关依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">  <modelVersion>4.0.0modelVersion>  <groupId>org.examplegroupId>  <artifactId>spring-ssmartifactId>  <packaging>warpackaging>  <version>1.0-SNAPSHOTversion>  <dependencies>    <dependency>      <groupId>org.springframeworkgroupId>      <artifactId>spring-webmvcartifactId>      <version>5.2.9.RELEASEversion>    dependency>    <dependency>      <groupId>com.fasterxml.jackson.coregroupId>      <artifactId>jackson-databindartifactId>      <version>2.9.0version>    dependency>    <dependency>      <groupId>org.mybatisgroupId>      <artifactId>mybatisartifactId>      <version>3.5.5version>    dependency>    <dependency>      <groupId>org.mybatisgroupId>      <artifactId>mybatis-springartifactId>      <version>1.3.0version>    dependency>    <dependency>      <groupId>mysqlgroupId>      <artifactId>mysql-connector-javaartifactId>      <version>5.1.32version>    dependency>    <dependency>      <groupId>org.springframeworkgroupId>      <artifactId>spring-jdbcartifactId>      <version>5.3.13version>    dependency>    <dependency>      <groupId>org.springframeworkgroupId>      <artifactId>spring-testartifactId>      <version>5.3.13version>    dependency>    <dependency>      <groupId>com.alibabagroupId>      <artifactId>druidartifactId>      <version>1.2.6version>    dependency>    <dependency>      <groupId>org.projectlombokgroupId>      <artifactId>lombokartifactId>      <version>1.18.28version>    dependency>    <dependency>      <groupId>javax.servletgroupId>      <artifactId>javax.servlet-apiartifactId>      <version>3.1.0version>      <scope>providedscope>    dependency>  dependencies>  <build>    <plugins>      <plugin>        <groupId>org.apache.tomcat.mavengroupId>        <artifactId>tomcat7-maven-pluginartifactId>        <version>2.2version>        <configuration>          <port>81port>          <path>path>        configuration>      plugin>    plugins>  build>project>

import lombok.Data;@Datapublic class User {    private int id;    private String username;    private String password;}------------------------------------------------------------------------package com.it.dao;import com.it.domain.User;import org.apache.ibatis.annotations.Delete;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.annotations.Update;import java.util.List;//用户增删改查接口public interface UserDao {    @Insert("INSERT INTO tb_user values (null,#{name},#{password}}})")    public void save(User user);    @Update("UPDATE tb_user set name=#{id},password=#{password} where id=#{id}}")    public void update(User user);    @Delete("DELETE from tb_user where id = #{id}}")    public void delete(Integer id);    @Select("SELECT * FROM tb_user")    public List<User> selectAll();    @Select("SELECT * FROM tb_user WHERE id=#{id}")    public User selectById(Integer id);}----------------------------------------------------------------------package com.it.service;import com.it.domain.User;import org.apache.ibatis.annotations.Delete;import org.apache.ibatis.annotations.Insert;import org.apache.ibatis.annotations.Select;import org.apache.ibatis.annotations.Update;import java.util.List;public interface UserService {        public boolean save(User user);        public boolean update(User user);        public boolean delete(Integer id);        public List<User> selectAll();        public User selectById(Integer id);}---------------------------------------------------------------------------package com.it.service.impl;import com.it.dao.UserDao;import com.it.domain.User;import com.it.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class UserServiceImpl implements UserService {    @Autowired //自动装配    private UserDao userDao;    public boolean save(User user) {        userDao.save(user);        return true;    }    public boolean update(User user) {        userDao.update(user);        return true;    }    public boolean delete(Integer id) {        userDao.delete(id);        return true;    }    public List<User> selectAll() {        return userDao.selectAll();    }    public User selectById(Integer id) {        return userDao.selectById(id);    }}------------------------------------------------------------------------package com.it.controller;import com.it.domain.User;import com.it.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.*;import java.util.List;@RestController@RequestMapping("/user")public class UserController {    @Autowired    private UserService userService;    @PostMapping    public boolean save(@RequestBody User user) {        return userService.save(user);    }    @PutMapping    public boolean update(@RequestBody User user) {        return userService.update(user);    }    @DeleteMapping("/{id}")    public boolean delete(@PathVariable Integer id) {        System.out.println(userService.delete(id));        return userService.delete(id);    }    @GetMapping    public List<User> selectAll() {        System.out.println(userService.selectAll());        return userService.selectAll();    }    @GetMapping("/{id}")    public User selectById(@PathVariable Integer id) {        return userService.selectById(id);    }}

4 测试

4.1 业务层接口测试

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4.2 表现层接口测试

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5.优化 -表现层数据封装

前端接受数据格式封装到code属性用于区分操作
将特殊消息封装到message（msg）属性中

public class Result{private Object data;private Integer code;private String msg;}

package com.it.controller;public class Code {    //成功    public static final Integer SAVE_OK = 20011;    public static final Integer DELETE_OK = 20021;    public static final Integer UPDATE_OK = 20031;    public static final Integer GET_OK = 20041;    public static final Integer PUT_OK = 20051;    //失败    public static final Integer SAVE_ERR = 20010;    public static final Integer DELETE_ERR = 20020;    public static final Integer UPDATE_ERR = 20030;    public static final Integer GET_ERR = 20040;    public static final Integer PUT_ERR = 20050;}----------------------------------------------------------------------------package com.it.controller;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;@Datapublic class Result {    private Object data;    private Integer code;    private String msg;    public Result(Integer code, String msg) {        this.code = code;        this.msg = msg;    }    public Result(Object data, Integer code) {        this.data = data;        this.code = code;    }    public Result(Object data, Integer code, String msg) {        this.data = data;        this.code = code;        this.msg = msg;    }}---------------------------------------------------------------------------import java.util.List;@RestController@RequestMapping("/user")public class UserController {    @Autowired    private UserService userService;    @PostMapping    public Result save(@RequestBody User user) {        boolean save = userService.save(user);        return new Result(save,save?Code.SAVE_OK:Code.SAVE_ERR);    }

在这里插入图片描述

6.异常处理

出现异常位置及原因

框架内部抛出异常：不合规使用
数据层抛出异常：外边服务器故障（超时访问）
业务层抛出异常：业务逻辑书写错误（遍历业务书写操作等）
表现层抛出异常：数据收集、校验等规则导致
工具类抛出异常：工具书写不严谨不健壮

项目异常分类

业务异常
原因：用户行为导致
解决：发送相应的信息传递给用户，提醒规范操作。

系统异常
原因：项目运行时可预计但无法避免的异常
解决：发送固定消息安抚用户；发送消息给处理人员；记录日志；

其他异常
原因：未预期的异常
解决：同上

解决：集中统一处理项目中出现的异常（异常处理器）

@RestControllerAdvice
作用：为Rest风格开发的控制器类做增强
.
@ExceptionHandler
作用：位于方法上方，设置指定异常处理方案，出现异常后终止原始控制器，转入当前方法执行。

package com.it.controller;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class ProjectExceptionAdvice {    @ExceptionHandler(Exception.class)    public Result doException(Exception e){        System.out.println("出现异常");        return new Result(500,"出错");    }}

步骤

自定义项目系统级异常
自定义业务级异常；
自定义异常编码；
触发自定义异常（模拟异常操作）；
拦截异常并处理异常；
测试结果

package com.it.controller;import lombok.Data;//自定义项目级异常@Datapublic class SystemException extends RuntimeException{    private Integer code;    public SystemException(String message, Throwable cause, Integer code) {        super(message);        this.code = code;    }        }

package com.it.controller;import lombok.Data;//自定义项目业务级异常@Datapublic class BusinessException extends RuntimeException{    private Integer code;    public BusinessException(String message, Integer code) {        super(message);        this.code = code;    }    public BusinessException(String message, Throwable cause, Integer code) {        super(message,cause);        this.code = code;    }}

//异常编码    public static final Integer SYSTEM_UNKNOW_ERROR = 50001;    public static final Integer SYSTEM_TIMEOUT_ERROR = 50002;    public static final Integer PROJECT_VALIDATE_ERROR = 60001;    public static final Integer PROJECT_BUSINESS_ERROR = 60002;

package com.it.service.impl;import com.it.controller.BusinessException;import com.it.controller.Code;import com.it.dao.UserDao;import com.it.domain.User;import com.it.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class UserServiceImpl implements UserService {    @Autowired //自动装配    private UserDao userDao;       //自定义异常    public User selectById(Integer id) {        if(id<0){            throw new BusinessException("请输入正确的id",Code.PROJECT_BUSINESS_ERROR);        }        return userDao.selectById(id);    }}

package com.it.controller;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.RestController;import org.springframework.web.bind.annotation.RestControllerAdvice;//拦截并处理异常@RestControllerAdvicepublic class ProjectExceptionAdvice {    @ExceptionHandler(Exception.class)    public Result doException(Exception e){        System.out.println("出现异常");        return new Result(500,"出错");    }    @ExceptionHandler(BusinessException.class)    public Result doBussinessException(Exception e){        System.out.println("出现业务异常");        return new Result(501,null,"出错");    }    @ExceptionHandler(SystemException.class)    public Result doSystemException(Exception e){        System.out.println("出现系统异常");        return new Result(500,"出错");    }}