SpringBoot中如何灵活的实现接口数据的加解密功能？
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数据是企业的第四张名片，企业级开发中少不了数据的加密传输，所以本文介绍下SpringBoot中接口数据加密、解密的方式。
本文目录
一、加密方案介绍
对接口的加密解密操作主要有下面两种方式：
- 自定义消息转换器
优势：仅需实现接口，配置简单。
劣势：仅能对同一类型的MediaType进行加解密操作，不灵活。
- 使用spring提供的接口RequestBodyAdvice和ResponseBodyAdvice
优势：可以按照请求的Referrer、Header或url进行判断，按照特定需要进行加密解密。
比如在一个项目升级的时候，新开发功能的接口需要加解密，老功能模块走之前的逻辑不加密，这时候就只能选择上面的第二种方式了，下面主要介绍下第二种方式加密、解密的过程。
二、实现原理
RequestBodyAdvice可以理解为在@RequestBody之前需要进行的 操作，ResponseBodyAdvice可以理解为在@ResponseBody之后进行的操作，所以当接口需要加解密时，在使用@RequestBody接收前台参数之前可以先在RequestBodyAdvice的实现类中进行参数的解密，当操作结束需要返回数据时，可以在@ResponseBody之后进入ResponseBodyAdvice的实现类中进行参数的加密。
RequestBodyAdvice处理请求的过程：
RequestBodyAdvice源码如下：
public interface RequestBodyAdvice {
boolean supports(MethodParameter methodParameter, Type targetType,
Class<? extends HttpMessageConverter<?>> converterType);
HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage, MethodParameter parameter,
Type targetType, Class<? extends HttpMessageConverter<?>> converterType) throws IOException;
Object afterBodyRead(Object body, HttpInputMessage inputMessage, MethodParameter parameter,
Type targetType, Class<? extends HttpMessageConverter<?>> converterType);
@Nullable
Object handleEmptyBody(@Nullable Object body, HttpInputMessage inputMessage, MethodParameter parameter,
Type targetType, Class<? extends HttpMessageConverter<?>> converterType);
}
调用RequestBodyAdvice实现类的部分代码如下：
protected <T> Object readWithMessageConverters(HttpInputMessage inputMessage, MethodParameter parameter,
Type targetType) throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {
MediaType contentType;
boolean noContentType = false;
try {
contentType = inputMessage.getHeaders().getContentType();
}
catch (InvalidMediaTypeException ex) {
throw new HttpMediaTypeNotSupportedException(ex.getMessage());
}
if (contentType == null) {
noContentType = true;
contentType = MediaType.APPLICATION_OCTET_STREAM;
}
Class<?> contextClass = parameter.getContainingClass();
Class<T> targetClass = (targetType instanceof Class ? (Class<T>) targetType : null);
if (targetClass == null) {
ResolvableType resolvableType = ResolvableType.forMethodParameter(parameter);
targetClass = (Class<T>) resolvableType.resolve();
}
HttpMethod httpMethod = (inputMessage instanceof HttpRequest ? ((HttpRequest) inputMessage).getMethod() : null);
Object body = NO_VALUE;
EmptyBodyCheckingHttpInputMessage message;
try {
message = new EmptyBodyCheckingHttpInputMessage(inputMessage);
for (HttpMessageConverter<?> converter : this.messageConverters) {
Class<HttpMessageConverter<?>> converterType = (Class<HttpMessageConverter<?>>) converter.getClass();
GenericHttpMessageConverter<?> genericConverter =
(converter instanceof GenericHttpMessageConverter ? (GenericHttpMessageConverter<?>) converter : null);
if (genericConverter != null ? genericConverter.canRead(targetType, contextClass, contentType) :
(targetClass != null && converter.canRead(targetClass, contentType))) {
if (logger.isDebugEnabled()) {
logger.debug("Read [" + targetType + "] as \\"" + contentType + "\\" with [" + converter + "]");
}
if (message.hasBody()) {
HttpInputMessage msgToUse =
getAdvice().beforeBodyRead(message, parameter, targetType, converterType);
body = (genericConverter != null ? genericConverter.read(targetType, contextClass, msgToUse) :
((HttpMessageConverter<T>) converter).read(targetClass, msgToUse));
body = getAdvice().afterBodyRead(body, msgToUse, parameter, targetType, converterType);
}
else {
body = getAdvice().handleEmptyBody(null, message, parameter, targetType, converterType);
}
break;
}
}
}
catch (IOException ex) {
throw new HttpMessageNotReadableException("I/O error while reading input message", ex);
}
if (body == NO_VALUE) {
if (httpMethod == null || !SUPPORTED_METHODS.contains(httpMethod) ||
(noContentType && !message.hasBody())) {
return null;
}
throw new HttpMediaTypeNotSupportedException(contentType, this.allSupportedMediaTypes);
}
return body;
}
从上面源码可以到当converter.canRead()和message.hasBody()都为true的时候，会调用beforeBodyRead()和afterBodyRead()方法，所以我们在实现类的afterBodyRead()中添加解密代码即可。
ResponseBodyAdvice处理响应的过程：
ResponseBodyAdvice源码如下：
public interface ResponseBodyAdvice<T> {
boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType);
@Nullable
T beforeBodyWrite(@Nullable T body, MethodParameter returnType, MediaType selectedContentType,
Class<? extends HttpMessageConverter<?>> selectedConverterType,
ServerHttpRequest request, ServerHttpResponse response);
}
调用ResponseBodyAdvice实现类的部分代码如下：
if (selectedMediaType != null) {
selectedMediaType = selectedMediaType.removeQualityValue();
for (HttpMessageConverter<?> converter : this.messageConverters) {
GenericHttpMessageConverter genericConverter =
(converter instanceof GenericHttpMessageConverter ? (GenericHttpMessageConverter<?>) converter : null);
if (genericConverter != null ?
((GenericHttpMessageConverter) converter).canWrite(declaredType, valueType, selectedMediaType) :
converter.canWrite(valueType, selectedMediaType)) {
outputValue = (T) getAdvice().beforeBodyWrite(outputValue, returnType, selectedMediaType,
(Class<? extends HttpMessageConverter<?>>) converter.getClass(),
inputMessage, outputMessage);
if (outputValue != null) {
addContentDispositionHeader(inputMessage, outputMessage);
if (genericConverter != null) {
genericConverter.write(outputValue, declaredType, selectedMediaType, outputMessage);
}
else {
((HttpMessageConverter) converter).write(outputValue, selectedMediaType, outputMessage);
}
if (logger.isDebugEnabled()) {
logger.debug("Written [" + outputValue + "] as \\"" + selectedMediaType +
"\\" using [" + converter + "]");
}
}
return;
}
}
}
从上面源码可以到当converter.canWrite()为true的时候，会调用beforeBodyWrite()方法，所以我们在实现类的beforeBodyWrite()中添加解密代码即可。
三、实战
新建一个spring boot项目spring-boot-encry，按照下面步骤操作。
- pom.xml中引入jar
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.60</version>
</dependency>
二探ReentrantLock非公平锁的加解锁过程