【Java】SSM入门开发流程总结

1.1 SSM整合流程

1. 创建工程
2. SSM整合
   • Spring
     • SpringConfig
   • MyBatis
     • MybatisConfig
     • JdbcConfig
     • jdbc.properties
   • SpringMVC
     • ServletConfig
     • SpringMvcConfig
3. 功能模块
   • 表与实体类
   • dao（接口+自动代理）
   • service（接口+实现类）
     • 业务层接口测试（整合JUnit）
   • controller
     • 表现层接口测试（PostMan）

SpringConfig

对于Spring需要配置SpringConfig，需要配置的内容如下：

• 设置为配置类：@Configuration
• 扫描Bean的路径：@ComponentScan
• 是否导入其他类，并加载其Bean：@Import
• 导入其他类的配置项：@PropertySource(“classpath:XXXXXX”)

MybatisConfig

对于Mybatis需要配置MybatisConfig、JdbConfig以及引入Jdbc.properties数据库配置文件。

1.JdbcConfig：

• 用@Value加载数据库连接信息，比如driver、username、password、url
• 设置DataSource类，把信息载入jdbc

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

• 判断是否要添加事务管理器

public  PlateformTransactionManager plateformtransactionManager(DataSource dataSource){
	DataSourceTransactionManager ds=new DataSourceTransactionManager();
	ds.setDataSource(datasource);
	return ds;
}

2.MybatisConfig

• 设置工厂Bean用于创建数据库会话：SqlSessionFactoryBean

@Bean
public SqlSessionFactoryBean sqlsessionFactoryBean(DataSource dataSource){
	SqlsessionFactoryBean factory = new SqlsessionFactoryBean();
	factory.setDataSource(datasource);
	return factory;
}

• 配置映射器：MapperScannerConfigurer

public MapperScannerConfigurer mapperScannerConfigurer(){
	MapperScannerConfigurer msc = new MapperScannerConfigurer();
	msc.setBasePackage("Hayaizo.dao");
	return msc;
}

SpringMVCConfig

SpringMVC需要配置SpringMVCConfig、ServletConfig

1.SpringMVCConfig

• 设置为配置类：@Configuration
• 设置Bean的扫描路径：@ComponentScan
• 启动Spring MVC框架：@EnableWebMvc
• 开启事务管理：@EnableTransationManagement

2.ServletConfig

• 设置为配置类：@Configuration
• 继承AbstractAnnotationConfigDispatcherServletInitilizer并实现方法

package Hayaizo.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.filter.CharacterEncodingFilter;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;

import javax.servlet.Filter;

@Configuration
public class ServletConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
    }

    //拦截请求
    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }

    //配置过滤器,处理中文乱码问题
    protected Filter[] getServletFilters(){
        CharacterEncodingFilter filter=new CharacterEncodingFilter();
        filter.setEncoding("UTF-8");
        return new Filter[]{filter};
    }
}

Controller层

• Restful控制器：@RestController
• 浏览器中访问资源路径：@RequestMapping(“/books”)
• 自动装配：@Autowired
• @PostMapping：处理HTTP POST请求的路径映射
  • @RequestParam：获取请求参数的值，不一定要填写参数
  • @PathVariable：获取URL路径中的变量值，一定要写参数
  • @RequestBody：用于接收Post请求体中的数据，可以把前端的json数据转换为对象
  • @RequestParam：用于接收Get请求URL上的参数

@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.selectById(id);
        Integer code=book!=null?Code.GET_OK:Code.GET_ERR;
        String msg=book!=null? "":"数据查询失败";
        return new Result(code,book,msg);
    }
    @GetMapping
    public Result selectAll() {
        List<Book> book=bookService.selectAll();
        Integer code=book!=null?Code.GET_OK:Code.GET_ERR;
        String msg=book!=null? "":"数据查询失败";
        return new Result(code,book,msg);
    }
}

SpringMvc中的异常处理

常用的注解：@RestControllerAdvice、@ExceptionHandler

@RestControllerAdvice：用于标识当前类为REST风格对应的异常处理器

@ExceptionHandler：标识用于处理哪种异常

@RestControllerAdvice
public class ProjectExceptionAdvice {
    //@ExceptionHandler用于设置当前处理器类对应的异常类型
    @ExceptionHandler(SystemException.class)
    public Result doSystemException(SystemException ex){
        //记录日志
        //发送消息给运维
        //发送邮件给开发人员,ex对象发送给开发人员
        return new Result(ex.getCode(),null,ex.getMessage());
    }

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

    //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 Result doOtherException(Exception ex){
        //记录日志
        //发送消息给运维
        //发送邮件给开发人员,ex对象发送给开发人员
        return new Result(Code.SYSTEM_UNKNOW_ERR,null,"系统繁忙，请稍后再试！");
    }
}

给静态资源放行

• 在SpringMvcSupport类中，此类继承于WebMvcConfigurationSupport
• 实现方法addResourceHandlers

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport{
    private ProjectInterceptor interceptor;
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
        registry.addResourceHandler("/css/**").addResourceLocations("/css/");
        registry.addResourceHandler("/js/**").addResourceLocations("/js/");
        registry.addResourceHandler("/plugins/**").addResourceLocations("/plugins/");
    }

    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor).addPathPatterns("/books","/books/*");
    }
}

interceptor拦截器

• 在controller接口层添加一个interceptor的包
• 创建一个拦截器的类ProjectorInterceptor
• ProjectorInterceptor实现HandlerInterceptor接口的方法

@Component
public class ProjectInterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle");
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        HandlerInterceptor.super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }
}

• 在SpringMvcSupport中添加上拦截器
• addInterceptor，通过registry来注册拦截器

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport{
    private ProjectInterceptor interceptor;
    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/pages/**").addResourceLocations("/pages/");
        registry.addResourceHandler("/css/**").addResourceLocations("/css/");
        registry.addResourceHandler("/js/**").addResourceLocations("/js/");
        registry.addResourceHandler("/plugins/**").addResourceLocations("/plugins/");
    }

    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor).addPathPatterns("/books","/books/*");
    }
}