• SSM(Spring-Mybatis-SpringMVC)

    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.Driver
jdbc.url=jdbc:mysql://localhost:3306/db1
jdbc.username=root
jdbc.password=123456

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    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;

//jdbcConfig

public 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;

//MyBatisConfig
public 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;
    }
}


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    web容器配置类

    SpringMVC

    • SpringMvcConfig
    • ServletConfig
    //ServletConfig
@Configuration
public 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")
@EnableWebMvc
public class SpringMvcConfig {
}



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    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 {
}


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    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

    在这里插入图片描述

    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>


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    import lombok.Data;

@Data
public 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 {
    /**
     * 保存
     * @param user
     * @return
     */
    public boolean save(User user);

    /**
     * 修改
     * @param user
     * @return
     */
    public boolean update(User user);

    /**
     * 删除
     * @param id
     * @return
     */
    public boolean delete(Integer id);

    /**
     * 查全部
     * @return
     */
    public List<User> selectAll();

    /**
     * 按id查找
     * @param id
     * @return
     */
    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;

@Service
public 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);
    }
}


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    4 测试

    4.1 业务层接口测试

    在这里插入图片描述

    4.2 表现层接口测试

    在这里插入图片描述
    在这里插入图片描述
    在这里插入图片描述

    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;
}

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    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;

@Data

public 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);
    }

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    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

    1. 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。
    2. 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；
    3. 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;

@RestController
public class ProjectExceptionAdvice {
    @ExceptionHandler(Exception.class)
    public Result doException(Exception e){
        System.out.println("出现异常");
        return new Result(500,"出错");
    }
}


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    步骤

    1. 自定义项目系统级异常
    2. 自定义业务级异常；
    3. 自定义异常编码；
    4. 触发自定义异常（模拟异常操作）；
    5. 拦截异常并处理异常；
    6. 测试结果
    package com.it.controller;

import lombok.Data;

//自定义项目级异常
@Data
public class SystemException extends RuntimeException{
    private Integer code;

    public SystemException(String message, Throwable cause, Integer code) {
        super(message);
        this.code = code;
    }
    
    
}


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    package com.it.controller;

import lombok.Data;

//自定义项目业务级异常
@Data
public 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;
    }
}


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    //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;

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    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;

@Service
public 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);
    }
}


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    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
@RestControllerAdvice
public 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");
    }
}


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    测试结果
    在这里插入图片描述
    在这里插入图片描述

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  • 原文地址：https://blog.csdn.net/meini32/article/details/132569931