springboot-base

Springboot 基础教育

最近看见恒宇少年出了新的技术框架，想起之前我还学习过他的Springboot的教程，原先有些心得感受重新编写一遍。

一、FastJson的使用

FastJson是阿里出的json处理库，在java开发与前端调试的接口基本上是使用json的方式，所以如果有个工具能够帮助解决json字符串转换的话是有非常迫切的需求，尤其是json转化为实体对象以及数组。

public static final Object parse(String text);// 把JSON文本parse 为JSONObject或者JSONArray

public static final JSONObject parseObject(String text);// 把JSON文本parse成JSONObject

public static final <T> T parseObject(String text,Class<T> clazz);// 把JSON 文本parse为JavaBean

public static final JSONArray parseArray(String text); // 把JSON文本parse成JSONArray

public static final <T> List<T> parseArray(String text, Class<T> clazz); // 把JSON文本parse为JavaBean集合

public static final String toJSONString(Object object); // 把JavaBean序列化为JSON文本

public static final String toJSONString(Object object, boolean prettyFormat); // 将JavaBean序列化为带格式的JSON文本

fastjson 还有比较常用的就是对实体类的注解了 @JSONField

@JSONField(name="Date",format="dd/MM/yyyy",ordinal=3)
private Date dateOfBirth;
// format 用于格式化
// ordinal 用于指定字段顺序
// serialize 一般是数字指定字段序列化

二、拦截器的使用

1、创建一个拦截器，让他集成HandlerIntercepter

public class SessionInterceptor implements HandlerInterceptor
{
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        System.out.println(request.getRequestURI());
        //登录不做拦截
        if(request.getRequestURI().equals("/user/login") || request.getRequestURI().equals("/user/login_view")){
            return true;
        }
        //验证session是否存在
        Object obj = request.getSession().getAttribute("_session_user");
        if(obj == null){
            response.sendRedirect("/user/login_view");
            return false;
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {

    }
}

2、把拦截器配置到Springboot的配置当中

@Configuration
public class SessionConfiguration extends WebMvcConfigurerAdapter{
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new SessionInterceptor()).addPathPatterns("/**");
    }
}

3、尝试使用日志的例子来做拦截器，日志管理有默认的一些框架，如Springboot默认是Logback，但是有的时候我更希望能有界面进行日志查询，那么我就会做一个实力类来做这块的记录，然后拦截器做好日志拦截

@Entity
@Table(name = "t_logger_infos")
@Data
public class LoggerEntity implements Serializable
{
    //编号
    @Id
    @GeneratedValue
    @Column(name = "ali_id")
    private Long id;
    //客户端请求ip
    @Column(name = "ali_client_ip")
    private String clientIp;
    //客户端请求路径
    @Column(name = "ali_uri")
    private String uri;
    //终端请求方式,普通请求,ajax请求
    @Column(name = "ali_type")
    private String type;
    //请求方式method,post,get等
    @Column(name = "ali_method")
    private String method;
    //请求参数内容,json
    @Column(name = "ali_param_data")
    private String paramData;
    //请求接口唯一session标识
    @Column(name = "ali_session_id")
    private String sessionId;
    //请求时间
    @Column(name = "ali_time",insertable = false)
    private Timestamp time;
    //接口返回时间
    @Column(name = "ali_returm_time")
    private String returnTime;
    //接口返回数据json
    @Column(name = "ali_return_data")
    private String returnData;
    //请求时httpStatusCode代码，如：200,400,404等
    @Column(name = "ali_http_status_code")
    private String httpStatusCode;
    //请求耗时秒单位
    @Column(name = "ali_time_consuming")
    private int timeConsuming;

JPA 就不说了，这里重点说明一下拦截器，仿拦截器的方式

// 写一个获取Spring上下文管理的Bean工具


public class LoggerInterceptor implements HandlerInterceptor
{
    //请求开始时间标识
    private static final String LOGGER_SEND_TIME = "_send_time";
    //请求日志实体标识
    private static final String LOGGER_ENTITY = "_logger_entity";

    /**
     * 进入SpringMVC的Controller之前开始记录日志实体
     * @param request 请求对象
     * @param response 响应对象
     * @param o
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        //创建日志实体
        LoggerEntity logger = new LoggerEntity();
        //获取请求sessionId
        String sessionId = request.getRequestedSessionId();
        //请求路径
        String url = request.getRequestURI();
        //获取请求参数信息
        String paramData = JSON.toJSONString(request.getParameterMap(),
                SerializerFeature.DisableCircularReferenceDetect,
                SerializerFeature.WriteMapNullValue);
        //设置客户端ip
        logger.setClientIp(LoggerUtils.getCliectIp(request));
        //设置请求方法
        logger.setMethod(request.getMethod());
        //设置请求类型（json|普通请求）
        logger.setType(LoggerUtils.getRequestType(request));
        //设置请求参数内容json字符串
        logger.setParamData(paramData);
        //设置请求地址
        logger.setUri(url);
        //设置sessionId
        logger.setSessionId(sessionId);
        //设置请求开始时间
        request.setAttribute(LOGGER_SEND_TIME,System.currentTimeMillis());
        //设置请求实体到request内，方面afterCompletion方法调用
        request.setAttribute(LOGGER_ENTITY,logger);
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object o, Exception e) throws Exception {
        //获取请求错误码
        int status = response.getStatus();
        //当前时间
        long currentTime = System.currentTimeMillis();
        //请求开始时间
        long time = Long.valueOf(request.getAttribute(LOGGER_SEND_TIME).toString());
        //获取本次请求日志实体
        LoggerEntity loggerEntity = (LoggerEntity) request.getAttribute(LOGGER_ENTITY);
        //设置请求时间差
        loggerEntity.setTimeConsuming(Integer.valueOf((currentTime - time)+""));
        //设置返回时间
        loggerEntity.setReturnTime(currentTime + "");
        //设置返回错误码
        loggerEntity.setHttpStatusCode(status+"");
        //设置返回值
        loggerEntity.setReturnData(JSON.toJSONString(request.getAttribute(LoggerUtils.LOGGER_RETURN),
                SerializerFeature.DisableCircularReferenceDetect,
                SerializerFeature.WriteMapNullValue));
        //执行将日志写入数据库
        LoggerJPA loggerDAO = getDAO(LoggerJPA.class,request);
        loggerDAO.save(loggerEntity);
    }

private <T> T getDao(Class<T> clazz,HttpServletRequest request){
    BeanFactory factory = WebApplicationContextUtils.getRequiredWebApplicationContext(request.getServletContext());
    return factory.getBean(clazz);
}