SSM(Spring-Mybatis-SpringMVC)

编程语言 2023-09-06 18:06:19 阅读次数: 0

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

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;
    }
}

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 {
    
    
}

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

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>4.0.0</modelVersion>
  <groupId>org.example</groupId>
  <artifactId>spring-ssm</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.9.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.9.0</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>3.5.5</version>
    </dependency>

    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>1.3.0</version>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.32</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>5.3.13</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>5.3.13</version>
    </dependency>

<!--    数据库连接池依赖-->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.2.6</version>
    </dependency>

    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.28</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.2</version>
        <configuration>
          <port>81</port>
          <path></path>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>


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);
    }
}

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;
}

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);
    }

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");
    }
}

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;
    }
    
    
}


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;
    }
}


//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;

@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);
    }
}


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");
    }
}

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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