JAVA && Spring && SpringBoot2.x — 學(xué)習(xí)目錄
1. 攔截器的基本使用
1.1 攔截器的實現(xiàn)類
- 實現(xiàn)Spring的HandlerInterceptor接口凳厢；
- 繼承實現(xiàn)HandlerInterceptor接口的類文兢，例如：HandlerInterceptorAdapter悍引；
1.2 HandlerInterceptor方法介紹
boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception;
void postHandle(
HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView)
throws Exception;
void afterCompletion(
HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
throws Exception;
- preHandler：業(yè)務(wù)處理器處理請求之前被調(diào)用，對用戶的request進行處理，若返回值為true，則繼續(xù)調(diào)用后續(xù)的攔截器和目標(biāo)方法；若返回值為false，則終止請求煞茫；這里可以加上登錄校驗，權(quán)限攔截等摄凡。
- postHandler：Controller執(zhí)行后但未返回視圖前調(diào)用該方法续徽，這里可以對返回用戶前的模型數(shù)據(jù)進行加工處理。
- afterCompletion：Controller執(zhí)行后且返回視圖后調(diào)用亲澡，可以得到Controller時的異常信息钦扭，這里可以記錄操作日志，資源清理等床绪。
1.3 將攔截器加入到MVC中
在SpringBoot 2.0以上客情， WebMvcConfigurerAdapter已過時，但是WebMvcConfigurerAdapter實際上是WebMvcConfigurer接口的空實現(xiàn)類癞己。故有兩種方法可以實現(xiàn)：
推薦使用：implements WebMvcConfigurer
1. @EnableWebMvc + implements WebMvcConfigurer
在擴展類中重寫父類的方法即可膀斋，這種方法會屏蔽springboot對SpringMVC的自動配置。
2. implements WebMvcConfigurer
在擴展類中重寫父類的方法即可痹雅，這種方法會使用springboot對SpringMVC的自動配置仰担。
3. extends WebMvcConfigurationSupport
在擴展類中重寫父類的方法即可，這種方法會屏蔽springboot對SpringMVC的自動配置绩社。
根據(jù)官方文檔摔蓝，盡量不要使用@EnableWebMvc注解赂苗，因為他會關(guān)閉自動配置。
詳情請了解——SpringBoot中對SpringMVC的自動配置
@Component
public class LogInterceptor implements HandlerInterceptor {
private final static Logger logger = LoggerFactory.getLogger(LogInterceptor.class);
//業(yè)務(wù)處理器處理請求之前被調(diào)用贮尉，對用戶的request進行處理
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
logger.info("【攔截器】-【已進入攔截器０枳獭！】");
return true;
}
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
}
}
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
@Autowired
private LogInterceptor logInterceptor;
//配置攔截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//指定攔截器猜谚，指定攔截路徑
registry.addInterceptor(logInterceptor).addPathPatterns("/**");
}
}
2. 攔截器的自定義注解
創(chuàng)建注解類败砂。
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target({ElementType.TYPE, ElementType.METHOD}) ////作用于類、接口等與方法上
@Retention(value = RetentionPolicy.RUNTIME)
public @interface MyLimit {
int intVal() default 5;
String stringVal() default "";
}
創(chuàng)建攔截器類-AnnotationInterceptor
@Component
public class AnnotationInterceptor implements HandlerInterceptor {
private final static Logger logger = LoggerFactory.getLogger(AnnotationInterceptor.class);
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
//判斷當(dāng)前被攔截的方法是否含有注解
boolean assignableFromMethod = handler.getClass().isAssignableFrom(HandlerMethod.class);//[額賽額包] 指定的
logger.info("當(dāng)前方法上是否有注解" + assignableFromMethod);
if (assignableFromMethod) {
//獲取當(dāng)前方法的自定義注解攔截器的注解
MyLimit methodAnnotation = ((HandlerMethod) handler).getMethodAnnotation(MyLimit.class);
logger.info("當(dāng)前方法的注解：" + methodAnnotation);
if (methodAnnotation == null) {
return true;
}
//獲取注解上的參數(shù)
int intVal = methodAnnotation.intVal();
String stringVal = methodAnnotation.stringVal();
logger.info("打印注解上的參數(shù)：[intVal={}][stringVal={}]", intVal, stringVal);
}
return true;
}
}
配置攔截器
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
@Autowired
private LogInterceptor logInterceptor;
@Resource
private AnnotationInterceptor annotationInterceptor;
//配置攔截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//指定攔截器魏铅，指定攔截路徑
registry.addInterceptor(logInterceptor).addPathPatterns("/**");
registry.addInterceptor(annotationInterceptor);
}
}
使用注解
@RequestMapping(value = "/get", method = RequestMethod.GET)
@ResponseBody
@MyLimit(stringVal = "哈哈吠卷，哈哈哈")
public String getUesr(@RequestParam(value = "str", required = false) Integer integer) {
try {
if (integer == 2) {
throw new RuntimeException("請求地址不合法");
}
}catch (Exception e){
logger.error("請求參數(shù)不合法",e);
}
logger.info("請求參數(shù)：str={}",integer);
SysQuartzJobConfig sysQuartzJobConfig = sysQuartzJobConfigMapper.selectByPrimaryKey(integer);
return JSON.toJSONString(sysQuartzJobConfig);
}
效果：
MyPrefix 16591 INFO com.Interceptor.impl.AnnotationInterceptor - 當(dāng)前方法上是否有注解true
MyPrefix 16591 INFO com.Interceptor.impl.AnnotationInterceptor - 當(dāng)前方法的注解：@com.Interceptor.annotation.MyLimit(intVal=5, stringVal=哈哈，哈哈哈)
MyPrefix 16592 INFO com.Interceptor.impl.AnnotationInterceptor - 打印注解上的參數(shù)：[intVal=5][stringVal=哈哈沦零，哈哈哈]
3. 獲取請求參數(shù)解決java.io.IOException: Stream closed
在攔截器中通過request.getInputStream();獲取body中的信息后，此時在Controller中使用@RequestBody注解獲取參數(shù)出現(xiàn)異常货岭。
流關(guān)閉異常出現(xiàn)原因分析
- 輸入流中含有一個“隱式指針”記錄當(dāng)前流讀取的位置路操，故一旦我們在攔截器中將讀取InputStream，那么后續(xù)無法使用@RequestBody注解千贯。
- 可以在【攔截器】之前使用【過濾器】屯仗，包裝request請求，重寫getInputStream()方法搔谴；
- 將數(shù)據(jù)保存到內(nèi)存Byte[]中魁袜，使用ByteArrayInputStream進行操作。
引入依賴
在springboot中敦第，無需引入峰弹。
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-core</artifactId>
<version>8.5.15</version>
</dependency>
新建攔截器
@Component
public class LogInterceptor implements HandlerInterceptor {
private final static Logger logger = LoggerFactory.getLogger(LogInterceptor.class);
//業(yè)務(wù)處理器處理請求之前被調(diào)用，對用戶的request進行處理
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception {
logger.info("【攔截器】-【已進入攔截器Ｎ吖鞠呈！】");
logger.info("【攔截器】-request的類型{}", request.getClass());
String bodyString = HttpHelper.getBodyString(request);
logger.info("bodyString的值：" + bodyString);
return true;
}
}
新建過濾器
public class HttpServletRequestReplacedFilter implements Filter {
private final static Logger logger = LoggerFactory.getLogger(HttpServletRequestReplacedFilter.class);
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
logger.info("【過濾器】-【已進入過濾器！】");
ServletRequest requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
chain.doFilter(requestWrapper, response);
}
@Override
public void destroy() {
}
}
包裝request
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {
private final static Logger logger = LoggerFactory.getLogger(BodyReaderHttpServletRequestWrapper.class);
private final byte[] body;
public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) {
super(request);
//獲取到請求體
logger.info("【過濾器】-【獲取請求的body信息】");
body = HttpHelper.getBodyString(request).getBytes(Charset.forName("UTF-8"));
}
//重寫方法
@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(getInputStream()));
}
@Override
public ServletInputStream getInputStream() throws IOException {
//節(jié)點流
final ByteArrayInputStream bais = new ByteArrayInputStream(body);
return new ServletInputStream() {
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener listener) {
//監(jiān)聽
logger.info("【攔截器】-【BodyReaderHttpServletRequestWrapper ReadListener:{}】", this);
}
@Override
public int read() throws IOException {
return bais.read();
}
};
}
}
讀取Body的工具類
public class HttpHelper {
private final static Logger logger = LoggerFactory.getLogger(HttpHelper.class);
public static String getBodyString(HttpServletRequest request) {
StringBuffer sb = new StringBuffer();
InputStream inputStream;
BufferedReader bufferedReader;
try {
//將數(shù)據(jù)保存到數(shù)組中右钾，每次讀取的時候蚁吝，都讀取一遍
inputStream = request.getInputStream();
//將字節(jié)數(shù)組當(dāng)做輸出的目的地
//字節(jié)流轉(zhuǎn)換為字符流（處理流）
bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
String line = "";
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
} catch (Exception e) {
logger.error("數(shù)據(jù)讀取異常", e);
}
return sb.toString();
}
}
攔截器過濾器加入到容器中
@Configuration
public class WebMvcConfiguration implements WebMvcConfigurer {
@Autowired
private LogInterceptor logInterceptor;
// @Resource
// private AnnotationInterceptor annotationInterceptor;
//配置攔截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//指定攔截器，指定攔截路徑
registry.addInterceptor(logInterceptor).addPathPatterns("/**");
// registry.addInterceptor(annotationInterceptor);
}
@Bean
public FilterRegistrationBean httpServletRequestReplacedRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new HttpServletRequestReplacedFilter());
registration.addUrlPatterns("/*");
registration.addInitParameter("paramName", "paramValue");
registration.setName("httpServletRequestReplacedFilter");
registration.setOrder(1);
return registration;
}
}
執(zhí)行日志
2019-07-02 16:40:07,598 INFO [22059] [http-nio-8080-exec-1] [] (DirectJDKLog.java:173): Initializing Spring DispatcherServlet 'dispatcherServlet'
2019-07-02 16:40:07,598 INFO [22059] [http-nio-8080-exec-1] [] (FrameworkServlet.java:524): Initializing Servlet 'dispatcherServlet'
2019-07-02 16:40:07,610 INFO [22071] [http-nio-8080-exec-1] [] (FrameworkServlet.java:546): Completed initialization in 12 ms
2019-07-02 16:40:07,620 INFO [22081] [http-nio-8080-exec-1] [] (HttpServletRequestReplacedFilter.java:22): 【過濾器】-【已進入過濾器舀射！】
2019-07-02 16:40:07,623 INFO [22084] [http-nio-8080-exec-1] [] (BodyReaderHttpServletRequestWrapper.java:26): 【過濾器】-【獲取請求的body信息】
2019-07-02 16:40:07,636 INFO [22097] [http-nio-8080-exec-1] [] (LogInterceptor.java:24): 【攔截器】-【已進入攔截器＞阶隆！】
2019-07-02 16:40:07,636 INFO [22097] [http-nio-8080-exec-1] [] (LogInterceptor.java:25): 【攔截器】-request的類型class com.filter.BodyReaderHttpServletRequestWrapper
2019-07-02 16:40:07,638 INFO [22099] [http-nio-8080-exec-1] [] (LogInterceptor.java:27): bodyString的值：{"age":"12","name":"liming"}
2019-07-02 16:40:07,797 INFO [22258] [http-nio-8080-exec-1] [] (UserController.java:41): 請求參數(shù)：str={"age":"12","name":"liming"}
