SpringBoot2.0实战 | 第五章：SpringBoot配置Filter过滤器
本章目标
学会在 SpringBoot 项目中配置 Filter，实现对请求出入参的日志打印。
操作步骤
添加依赖
引入 Spring Boot Starter 父工程
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.0.5.RELEASEversion>
parent>
引入 spring-boot-starter-web 的依赖
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
编码
- 编写 Filter
实现对 application/json 请求的拦截，因为请求内容使用流，所以需要多一次封装
public class TraceFilter extends GenericFilterBean {
private static final Logger log = LoggerFactory.getLogger(TraceFilter.class);
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest) servletRequest;
HttpServletResponse response = (HttpServletResponse) servletResponse;
long startTime = System.currentTimeMillis();
// 封装流
TraceServletRequestWrapper requestWrapper = new TraceServletRequestWrapper(request);
TraceServletResponseWrapper responseWrapper = new TraceServletResponseWrapper(response);
// 执行
chain.doFilter(requestWrapper, responseWrapper);
long endTime = System.currentTimeMillis();
// 执行日志打印
String requestBody = getRequestBody(requestWrapper);
String responseBody = getResponseBody(responseWrapper);
StringBuilder builder = new StringBuilder();
if (requestBody == null || requestBody.isEmpty()) {
requestBody = "{}";
}
if (responseBody == null || responseBody.isEmpty()) {
responseBody = "{}";
}
builder.append("请求url:").append(request.getRequestURL()).append("|");
builder.append("耗时:").append(endTime - startTime).append("-");
builder.append("请求内容:").append(requestBody).append(",");
builder.append("返回内容:").append(responseBody).append(",");
logger.info(builder.toString());
}
private String getResponseBody(TraceServletResponseWrapper responseWrapper) {
TraceServletOutputStream traceOutputStream = responseWrapper.getTraceOutputStream();
String content;
if ((null != traceOutputStream) && (content = traceOutputStream.getContent()) != null && !content.isEmpty()) {
return new String(content.getBytes(), StandardCharsets.UTF_8);
}
return null;
}
private String getRequestBody(TraceServletRequestWrapper requestWrapper) {
TraceServletInputStream traceInputStream = requestWrapper.getTraceInputStream();
if (traceInputStream != null) {
return new String(traceInputStream.getContent().getBytes(), StandardCharsets.UTF_8);
}
return null;
}
}
请求封装
public class TraceServletRequestWrapper extends HttpServletRequestWrapper {
TraceServletInputStream traceInputStream;
public TraceServletRequestWrapper(HttpServletRequest request) {
super(request);
}
@Override
public ServletInputStream getInputStream() throws IOException {
if (traceInputStream == null) {
traceInputStream = new TraceServletInputStream(super.getInputStream());
}
return traceInputStream;
}
public TraceServletInputStream getTraceInputStream() {
return traceInputStream;
}
}
响应封装
public class TraceServletResponseWrapper extends HttpServletResponseWrapper {
private TraceServletOutputStream traceOutputStream;
private HttpServletResponse response;
public TraceServletResponseWrapper(HttpServletResponse response) {
super(response);
this.response = response;
}
@Override
public PrintWriter getWriter() throws IOException {
return null;
}
@Override
public ServletOutputStream getOutputStream() throws IOException {
if (null == traceOutputStream) {
traceOutputStream = new TraceServletOutputStream(super.getOutputStream());
}
return traceOutputStream;
}
public TraceServletOutputStream getTraceOutputStream() {
return traceOutputStream;
}
}
输入流封装
public class TraceServletInputStream extends ServletInputStream {
ServletInputStream servletInputStream;
private StringBuilder buffer;
public TraceServletInputStream(ServletInputStream inputStream) {
this.servletInputStream = inputStream;
buffer = new StringBuilder();
}
@Override
public boolean isFinished() {
return false;
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setReadListener(ReadListener readListener) {
}
@Override
public int read() throws IOException {
int data = servletInputStream.read();
buffer.append((char)data);
return data;
}
@Override
public int read(byte b[]) throws IOException {
int data = servletInputStream.read(b);
if(data > 0) {
buffer.append(new String(b));
}
return data;
}
@Override
public int read(byte b[], int off, int len) throws IOException {
int data = servletInputStream.read(b, off, len);
if(data > 0) {
buffer.append(new String(b, off, data));
}
return data;
}
@Override
public int readLine(byte[] b, int off, int len) throws IOException {
int data = servletInputStream.readLine(b, off, len);
if(data > 0) {
buffer.append(new String(b, off, data));
}
return data;
}
public String getContent() {
return buffer.toString();
}
}
输出流封装
public class TraceServletOutputStream extends ServletOutputStream {
private ServletOutputStream outputStream;
private StringBuilder buffer;
public TraceServletOutputStream(ServletOutputStream outputStream) {
this.outputStream = outputStream;
buffer = new StringBuilder();
}
@Override
public void write(int b) throws IOException {
outputStream.write(b);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
super.write(b, off, len);
if(b.length > 0) {
buffer.append(new String(b, off, len));
}
}
@Override
public void write(byte[] b) throws IOException {
super.write(b);
if(b.length > 0) {
buffer.append(new String(b));
}
}
@Override
public boolean isReady() {
return false;
}
@Override
public void setWriteListener(WriteListener writeListener) {
}
public String getContent() {
return buffer.toString();
}
}
- 注册 Filter
@Configuration
public class WebConfig {
@Bean
public FilterRegistrationBean traceFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new TraceFilter());
registration.addUrlPatterns("/*");
registration.setOrder(1);
return registration;
}
}
- 编写 controller 接口
使用 @RequestBody 方式接收参数
@RestController
public class HelloController {
@PostMapping("/hello")
public Map<String, Object> hello(@RequestBody Map<String, Object> map) {
return map;
}
}
- 编写项目启动类
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
验证结果
使用 Postman 进行请求
启动服务，使用 postman 进行请求，请求体为 {"name":"user1","sex":1,"birthday":"2000-01-01"}
使用测试用例验证
因为使用测试用例时不会主动加载 Filter，所以需要在启动测试用例环境时进行注册
MockMvcBuilders.webAppContextSetup(webApplicationContext).addFilter(new TraceFilter()).build();
测试用例代码如下：
@RunWith(SpringRunner.class)
@WebAppConfiguration
@SpringBootTest(classes = Application.class)
public class FilterTest {
private MockMvc mvc;
@Autowired
private WebApplicationContext webApplicationContext;
@Before
public void setUp() {
mvc = MockMvcBuilders.webAppContextSetup(webApplicationContext)
.addFilter(new TraceFilter())
.build();
}
@Test
public void test() throws Exception {
MvcResult mvcResult = mvc.perform(
MockMvcRequestBuilders
.post("/hello")
.contentType(MediaType.APPLICATION_JSON_UTF8)
.content("{\"name\":\"user1\",\"sex\":1,\"birthday\":\"2000-01-01\"}")
)
.andDo(MockMvcResultHandlers.print())
.andReturn();
Assert.assertEquals(200, mvcResult.getResponse().getStatus());
}
}
源码地址
本章源码 : https://gitee.com/gongm_24/spring-boot-tutorial.git
总结
Filter 用途很多，本文主要不是讲解 Filter 如何使用，而是讲解如何在 SpringBoot 项目中进行 Filter 的注册。
Filter 注册主要是依赖于 FilterRegistrationBean 类，这只是一种方式，另外 Filter 也可以通过 @WebFilter 注解进行自动注册。