Java—SpringMvc常用配置文件

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;

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

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

@Bean：定义第三方的插件bean类 

 MybatisConfig：

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

ServletConfig：

public class ServletConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
    //加载Spring配置类
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }
    //加载SpringMVC配置类
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
    }
    //设置SpringMVC请求地址拦截规则
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
    //设置post请求中文乱码过滤器
    @Override
    protected Filter[] getServletFilters() {
        CharacterEncodingFilter filter = new CharacterEncodingFilter();
        filter.setEncoding("utf-8");
        return new Filter[]{filter};
    }
}

SpringConfig：

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

@Configuration：标注为配置文件 

@ComponentScan：标注要扫描的目录（Spring主要负责service层）

@PropertySource：加载数据库jdbc文件，classPath通过path加载

@Import：加载需要加载的Bean文件

@EnableTransactionManagement：允许启用事务回滚机制

SpringMvcConfig：

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

@EnableWebMvc：启用Spring-Mvc功能 

resources\jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/数据库名
jdbc.username=账户名
jdbc.password=账户密码

项目主要文件层级：

项目Test层级：

Test文件内容：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes = SpringConfig.class)
public class BookServiceTest {
    @Autowired
    private BookService bookService;

    @Test
    public void testGetById(){
        Book book = bookService.getById(15);
        System.out.println(book);
    }

    @Test
    public void testGetAll(){
        List<Book> all = bookService.getAll();
        System.out.println(all);
    }
}

@Autowired：自动从spring中取出实体类 

@Test：定义为测试类

Dao层：

主要用于数据层，书写sql语句

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();
}

Sql方法注解：@Insert、@Update、@Select、@Delete 

domain层：

定义数据模态层

public class Book {
    private Integer id;
    private String type;
    private String name;
    private String description;
    //省略Getter和Setter...
}

Service服务层：

@Transactional
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();
}

@Transactional：定义该Service允许事务回滚

Service的实体类Impl：

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

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

@Service：Service层的Impl必须声明为Service才会被Spring自动收集

异常处理类

@RestControllerAdvice
public class ProjectExceptionAdvice {
//除了自定义的异常处理器，保留对Exception类型的异常处理，用于处理非预期的异常
@ExceptionHandler(Exception.class)
public void doException(Exception ex){
System.out.println("嘿嘿,异常你哪里跑！")
}
}

@RestControllerAdvice：@ResponseBody风格的异常处理

@RestControllerAdvice=@ControllerAdvice+@ResponseBody

如异常处理为文件夹，须在SpringMvcConfig中配置ComponentScan

异常分类

分为三类：

1.业务异常(Business Excption)

数据遗漏、提示规范操作

public class BusinessException extends RuntimeException {
    private Integer code;

    public Integer getCode() {
        return code;
    }

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

    public BusinessException(Integer code, String message) {
        super(message);
        this.code = code;
    }

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

2.系统异常(System Excption)

数据库、服务器宕机

public class SystemException extends RuntimeException {
    private Integer code;

    public Integer getCode() {
        return code;
    }

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

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

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

3.其他异常(Excption)

未预期到的异常

整合异常处理

@RestControllerAdvice
public class ProjectExceptionAdvice {
    @ExceptionHandler(SystemException.class)
    public Result doSystemException(SystemException ex) {
        // 记录日志
        // 发送消息给运维
        // 发送邮件给开发
        return new Result(ex.getCode(), null, ex.getMessage());
    }

    @ExceptionHandler(BusinessException.class)
    public Result doBusinessException(BusinessException ex) {
        return new Result(ex.getCode(), null, ex.getMessage());
    }

    @ExceptionHandler(Exception.class)
    public Result doException(Exception ex) {
        return new Result(Code.SYSTEM_UNKNOW_ERR, null, "系统繁忙，请稍后重试");
    }
}

拦截器开发

步骤1：创建ProjectInterceptor，重写HandlerInterceptor

@Component
public class ProjectInterceptor implements HandlerInterceptor {
    @Override
    //原始方法调用前执行的内容
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle...");
        return true;
    }

    @Override
    //原始方法调用后执行的内容
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle...");
    }

    @Override
    //原始方法调用完成后执行的内容
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion...");
    }
}

步骤2：修改SpringMvcConfig，具有一定侵入性

public class SpringMvcConfig implements WebMvcConfigurer {
    @Autowired
    private ProjectInterceptor projectInterceptor;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //配置多拦截器
        registry.addInterceptor(projectInterceptor).addPathPatterns("/books", "/books/*");
    }
}

通过拦截器获取参数

request：请求体        response：响应体        handler：被调用的处理器对象

preHandle

获取header中内容：request.getHeader(头部key名)

handler：

HandlerMethod hm = (HandlerMethod) handler;
String methodName = hm.getMethod().getName();

postHandle

@Configuration
@ComponentScan({"com.example.controller", "com.example.exception"})
@EnableWebMvc
public class SpringMvcConfig implements WebMvcConfigurer {
    @Autowired
    private ProjectInterceptor projectInterceptor;
    @Autowired
    private ProjectInterceptor2 projectInterceptor2;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //配置多拦截器
        registry.addInterceptor(projectInterceptor).addPathPatterns("/books", "/books/*");
        //新添加的拦截器
        registry.addInterceptor(projectInterceptor2).addPathPatterns("/books", "/books/*");
    }
}

原文地址：https://blog.csdn.net/qq_20497071/article/details/140543789

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