解决spring设置filter过滤器结合rest风格获取post请求body参数输入流问题

           由于最近在使用spring+jersey开发要设置基于servlet的filter。当在filter中通过request.getReader或者getInputStream读取body中的json参数处理时，由于rest风格的jersey框架底层亦是基于同样原理读取post请求body中参数。因为request自身的原则：getReader或者getInputStream只能调用其中一个且只有一次可以正常获取body中内容，导致在filter中通过getReader第一次读取body中参数成功，当放行时，jersey中控制器执行时候，会出现异常：

java.lang.IllegalStateException: getReader() has already been called for this request。

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###           运行系统：windows8

###          JDK版本 ： JDK1.7

###          框架：spring3x + jersey2.x

###          开发IDE：MyEclipse

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1.0 在web.xml中配置spring过滤器filter，集成自定义filter

<filter>
<filter-name>DelegateFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
<init-param>
<param-name>targetBeanName</param-name>
<param-value>myFilter</param-value> <!-- 自定义拦截器-->
</init-param>
<init-param>
<param-name>targetFilterLifecycle</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>DelegateFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

2.0在spring配置文件application.xml中定义自定义filterbean。

<bean id="myFilter" class="com.cybbj.action.filter.FilterPost"></bean>

PS:若是在filter中想使用springIOC容器中其他bean.如其他service类。那么可以在该bean中配置。
例如在filter中需要注入公用commonSerivce
public class myFilter implements Filter{
private CommonService commonService;

//需要setter
.......
}

要想使用commonService而不抛出空指针异常，需要在bean中配置依赖：
<bean id="myFilter" class="com.cybbj.action.filter.FilterPost">
<property name="commonService"> <ref bean="commonService"/> <!-- 其中commonService是通过注解或者xml配置到IOC容器中的类--></property></bean>

3.0 自定义filter
原始代码与运行结果如下：

public class FilterPost implements Filter{

private Log log = LogFactory.getLog(FilterPost.class);

String param = "";

public void destroy() {
// TODO Auto-generated method stub

}

public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = null;
if(req instanceof HttpServletRequest) {
request = (HttpServletRequest)req;
}

if("POST".equalsIgnoreCase(request.getMethod())){
param = this.getBodyString(request.getReader());
log.info("filter读取body中的参数>>>>>>>>>"+param);
chain.doFilter(request, res);
}

}

public void init(FilterConfig config) throws ServletException {

}

//获取request请求body中参数
public static String getBodyString(BufferedReader br) {
String inputLine;
String str = "";
try {
while ((inputLine = br.readLine()) != null) {
str += inputLine;
}
br.close();
} catch (IOException e) {
System.out.println("IOException: " + e);
}
return str;
}

4.0基于jersey的controller中post请求处理

@POST
@Path("/postJson")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
public Map<String, String> postByJson(Map<String, Object> jsonParam) {

JSONObject jo = new JSONObject(jsonParam);
System.out.println(jsonParam);
Map<String, String> param = new HashMap<String, String>();
param.put("name", jo.getString("name").length()==0? "" : jo.getString("name"));
param.put("age", jo.getString("age").length()==0  ? "" :jo.getString("age"));
param.put("status", "200");
param.put("Msg", "ok,success");
return param;
}

5. 抛出异常
java.lang.IllegalStateException: getReader() has already been called for this request
at org.apache.catalina.connector.Request.getInputStream(Request.java:1085)

解决方法：

结合JODD开源框架，且在Filter中将ServletRequest替换为ServletRequestWrapper 来解决该问题。

A：添加jodd支持：

在pom.xml中添加对jodd的依赖：

<!-- https://mvnrepository.com/artifact/org.jodd/jodd-core -->
<dependency>
</span><groupId>org.jodd</groupId>
</span><artifactId>jodd-core</artifactId>
</span><version>3.4.8</version>
</dependency>

B:结合jodd创建自定义ServletRequestWrapper

public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper{

private final byte[] body; //用于保存读取body中数据

public BodyReaderHttpServletRequestWrapper(HttpServletRequest request)
throws IOException {
super(request);
body = StreamUtil.readBytes(request.getReader(), "UTF-8");
}

@Override
public BufferedReader getReader() throws IOException {
return new BufferedReader(new InputStreamReader(getInputStream()));
}

@Override
public ServletInputStream getInputStream() throws IOException {
final ByteArrayInputStream bais = new ByteArrayInputStream(body);
return new ServletInputStream() {

@Override
public int read() throws IOException {
return bais.read();
}

@Override
public boolean isFinished() {
// TODO Auto-generated method stub
return false;
}

@Override
public boolean isReady() {
// TODO Auto-generated method stub
return false;
}

@Override
public void setReadListener(ReadListener arg0) {
// TODO Auto-generated method stub

}
};
}
}

C:用wrapper替换request修改filter

public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
String method = "GET";
ServletRequest requestWrapper = null;
if(req instanceof HttpServletRequest) {
method = ((HttpServletRequest) req).getMethod();
requestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) req);  //替换
}

if("POST".equalsIgnoreCase(method)){
param = this.getBodyString(requestWrapper.getReader());
log.info("filter读取body中的参数>>>>>>>>>"+param);
chain.doFilter(requestWrapper, res);
}

D:请求测试



请求成功................

参考文章：http://liwx2000.iteye.com/blog/1542431