SSM整合

小卡斯蒂
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SSM整合流程

image.png

2.SSM整合

spring

先导入坐标(一大堆)

创建SpringConfig配置类

@Configuration
@ComponentScan({"com.itheima.service"})

public class SpringConfig {
}

mybatis与spring整合

image.png 1.

创建jdbcConfig，MybatisConfig配置类，jdbc.propeties并在里面输入相应信息

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;
    @Bean
    public DataSource dataSource(){
        DruidDataSource dataSource = new DruidDataSource();
        dataSource.setDriverClassName(driver);
        dataSource.setUrl(url);
        dataSource.setUsername(username);
        dataSource.setPassword(password);
        return dataSource;
    }

public class MybatisConfig{
    @Bean
    public SqlSessionFactoryBean sqlSessionFactory(DataSource dataSource){
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSource);
        factoryBean.setTypeAliasesPackage("com.itheima.domain");
        return factoryBean;
    }
    //扫描映射
    @Bean
    public MapperScannerConfigurer mapperScannerConfigurer(){
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        msc.setBasePackage("com.itheima.dao");
        return msc;
    }

jdbc.propeties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm_db
jdbc.username=root
jdbc.password=z15788901

再在SpringConfig配置类中加入如下注解

@Configuration
@ComponentScan({"com.itheima.service"})
@PropertySource("jdbc.properties")
@Import({JdbcConfig.class,MybatisConfig.class})
public class SpringConfig {
}

这样就完成了spring整合mybatis

spring整合springMVC

1.创建SpringMvcConfig，加上如下注解

@Configuration
@ComponentScan("com.itheima.controller")
@EnableWebMvc
public class SpringMvcConfig {

}

2.创建ServletConfig并继承AbstractAnnotationConfigDispatcherServletInitializer重写方法

public class ServletConfig extends AbstractAnnotationConfigDispatcherServletInitializer {

    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }

    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
    }
    //拦截所有请求
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

这样，就完成了spring整合springMVC的操作。

3.功能模块

image.png 1.先导入表与创建实体类

2.dao

public interface BookDao {
    @Insert("insert into tbl_book (type,name,description) values(#{type},#{name},#{description})")
    public void save(Book book);
    @Update("update tbl_book set type = #{type}, name = #{name}, description = #{description} where id = #{id}")
    public void update(Book book);
    @Delete("delete from tbl_book where id = #{id}")
    public void delete(Integer id);
    @Select("select * from tbl_book where id = #{id}")
    public Book getById(Integer id);
    @Select("select * from tbl_book")
    public  List<Book> getAll();
}

3.BookServiceImpl

public class BookServiceImpl implements BookService {
    @Autowired
    private BookDao bookDao;

    public boolean save(Book book) {
        bookDao.save(book);
        return true;
    }

    public boolean update(Book book) {
        bookDao.update(book);
        return true;
    }

    public boolean delete(Integer id) {
        bookDao.delete(id);
        return true;
    }

    public Book getById(Integer id) {
        return bookDao.getById(id);
    }

    public List<Book> getAll() {
        return bookDao.getAll();
    }
}

4.BookController

@RestController
@RequestMapping("/books")
public class BookController {

    @Autowired
    private BookService bookService;

    @PostMapping
    public boolean save(@RequestBody Book book) {
        return bookService.save(book);
    }

    @PutMapping
    public boolean update(@RequestBody Book book) {
        return bookService.update(book);
    }

    @DeleteMapping("/{id}")
    public boolean delete(@PathVariable Integer id) {
        return bookService.delete(id);
    }

    @GetMapping("/{id}")
    public Book getById(@PathVariable Integer id) {
        return bookService.getById(id);
    }

    @GetMapping
    public List<Book> getAll() {
        return bookService.getAll();
    }

5.BookService

public interface BookService {
    /**
     * 保存
     * @param book
     * @return
     */
    public boolean save(Book book);

    /**
     * 修改
     * @param book
     * @return
     */
    public boolean update(Book book);

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

    /**
     * 按id查询
     * @param id
     * @return
     */
    public Book getById(Integer id);

    /**
     * 查询全部
     * @return
     */
    public List<Book> getAll();
}

业务层接口测试

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class BookServiceTest {
    @Autowired
    private BookService bookService;
    @Test
    public void test(){
        Book book = bookService.getById(2);
        System.out.println(book);
    }
    @Test
    public void testAll(){
        List<Book> all = bookService.getAll();
        System.out.println(all);
    }

再用POSTman测试各网页即可。

事务处理

1.开启注解式事务驱动

在springconfig类中加入如下注解

@EnableTransactionManagement

2.配置事务管理器

在jdbcconfig类中加入如下方法

@Bean
public PlatformTransactionManager transactionManager(DataSource dataSource){
        DataSourceTransactionManager ds = new DataSourceTransactionManager();
        ds.setDataSource(dataSource);
        return ds;
    }

3.添加事务，把事务的Transactional添加到接口上

在service接口中加入如下注解

@Transactional

image.png

下面是高级部分：

表现层数据封装

目的：统一成相同格式，称之为表现层与前端数据传输协议

方案：创建结果模型类，

封装数据到data属性中，

封装操作结果到code属性中，

封装特殊消息到message(msg)属性中

image.png

image.png 步骤：

1.造result类

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

    public Result(Object data, Integer code) {
        this.data = data;
        this.code = code;
    }

    public Result() {
    }

    public Result(Object data, Integer code, String msg) {
        this.data = data;
        this.code = code;
        this.msg = msg;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }

    public Integer getCode() {
        return code;
    }

    public void setCode(Integer code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

2.创建code类，用来表示返回的code为什么值时表示成功，失败

PS:Code类的常量设计也不是固定的，可以根据需要自行增减，例如将查询再进行细分为GET_OK，GET_ALL_OK，GET_PAGE_OK

public class code {
    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 SAVE_ERR = 20010;
    public static final Integer DELETE_ERR = 20020;
    public static final Integer UPDATE_ERR = 20030;
    public static final Integer GET_ERR = 20040;
}

3.在BookController中修改如下

@RestController
@RequestMapping("/books")
public class BookController {

    @Autowired
    private BookService bookService;

    @PostMapping
    public Result save(@RequestBody Book book) {
        boolean flag = bookService.save(book);
        return new Result(flag?code.SAVE_OK:code.SAVE_ERR,flag);
    }

    @PutMapping
    public Result update(@RequestBody Book book) {
        boolean flag = bookService.update(book);
        return new Result(flag?code.UPDATE_OK:code.UPDATE_ERR,flag);
    }

    @DeleteMapping("/{id}")
    public Result delete(@PathVariable Integer id) {
        boolean flag = bookService.delete(id);
        return new Result(flag?code.DELETE_OK:code.DELETE_ERR,flag);
    }

    @GetMapping("/{id}")
    public Result getById(@PathVariable Integer id) {
        Book book = bookService.getById(id);
        Integer code1 = book != null ? code.GET_OK:code.GET_ERR;
        String msg = book != null ? "":"查询失败";
        return new Result(code1,book,msg);
    }

    @GetMapping
    public Result getAll() {
        List<Book> bookList = bookService.getAll();
        Integer code1 = bookList != null ? code.GET_OK:code.GET_ERR;
        String msg = bookList != null ? "":"查询失败";
        return new Result(code1,bookList,msg);
    }

异常处理器

出现异常现象的常见位置与常见诱因如下:

框架内部抛出的异常:因使用不合规导致

数据层抛出的异常:因外部服务器故障导致（例如∶服务器访问超时)

业务层抛出的异常:因业务逻辑书写错误导致（例如:遍历业务书写操作，导致索引异常等)

表现层抛出的异常:因数据收集、校验等规则导致（例如:不匹配的数据类型间导致异常)

工具类抛出的异常:因工具类书写不严谨不够健壮导致（例如:必要释放的连接长期未释放等)

1．各个层级均出现异常，异常处理代码书写在哪一层？

所有的异常均抛出到表现层进行处理

2．表现层处理异常，每个方法中单独书写，代码书写量巨大且意义不强，如何解决?

AOP思想

image.png 代码实现如下

//用来做异常处理的类
@RestControllerAdvice
public class ProjectExceptionAdvice {
    @ExceptionHandler(Exception.class)
    public void doException(Exception ex){
        System.out.println("异常我lei了");
    }

上面讲述的是表现层如何抛出异常，那么，数据层，业务层的异常该如何整合到表现层呢？

项目异常处理方案

项目异常分类：

  • 业务异常(BusinessException)

    • 规范的用户行为产生的异常术
    • 不规范的用户行为操作产生的异常

  • 系统异常(SystemException)

    • 项目运行过程中可预计且无法避免的异常

  • 其他异常(Exception)

    • 编程人员未预期到的异常

image.png

public class ProjectExceptionAdvice {
    @ExceptionHandler(SystemException.class)
    public Result doSystemException(SystemException ex){//系统异常
        //记录日志
        //发送消息给运维
        //发送邮件给开发人员
        return new Result(ex.getCode(),null,ex.getMessage());
    }
    @ExceptionHandler(BussinessException.class)//业务异常
    public Result BussinessException(BussinessException bx){
        return new Result(bx.getCode(),null,bx.getMessage());
    }

    @ExceptionHandler(Exception.class)
    public Result doException(Exception ex){//其他异常
        //记录日志
        //发送消息给运维
        //发送邮件给开发人员
        System.out.println("异常我lei了");
        return new Result(code.SYSTEM_UNKNOWN_ERR,null,"系统繁忙，请稍后再试");
    }

public Book getById(Integer id) {
    if(id==1){
        throw new BussinessException(code.BUSINESS_ERR,"请你自重");
    }
    //将可能出现的异常进行包装，转换成自定义异常
    try{
        int i = 1/0;
    }catch (Exception e){
        throw new SystemException(code.SYSTEM_ERR,"服务器访问超时，请重试",e);
    }
    return bookDao.getById(id);
}
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