背景：在SPRING 框架之中， 有一个服务端需要提供多种形态的服务，这里的多种形态只是返回值得展示形式（其实 数据内在逻辑完全一样）， 比如：

形式1： JSONP({“key1”: value1, "key2":value2, "key3":value3, ....})

形式2： {“key1”: value1, "key2":value2, "key3":value3, ....}

为了使得后台业务处理代码一样（不做任何区分），现在理由过滤器，对返回接口进行处理，根据需要加上 ：JSONP(...)

主要实现步骤如下：

1. 在web.xml 中配置过滤器

RewriteResponsecom.robin.filter.RewriteResponse RewriteResponse/* // 斜杠星代表匹配任何请求

2. 重点在于RewriteResponse 过滤器

public class RewriteResponseFilter extends Filter {

public String description() { // TODO Auto-generated method stub return null; }

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException { // TODO Auto-generated method stub ResponseWrapper responseWrapper = new ResponseWrapper((HttpServletResponse) response);

try { chain.doFilter(request, responseWrapper); } catch (ServletException e) { // TODO Auto-generated catch block e.printStackTrace(); }

String responseContent = new String(responseWrapper.getDataStream());

RestResponse fullResponse = new RestResponse(205, "OK-MESSAGE",responseContent);

byte[] responseToSend = restResponseBytes(fullResponse);

response.getOutputStream().write(responseToSend);

}

private byte[] restResponseBytes(RestResponse response) throws IOException { String serialized = new ObjectMapper().writeValueAsString(response); return serialized.getBytes("UTF-8"); }

}

3. 通用业务类（用于返回）

public class RestResponse implements Serializable { private int status;

private String message; private Object data;

public RestResponse(int status, String message, Object data) { this.status = status; this.message = message; this.data = data; } public int getStatus() { return status; }

public void setStatus(int status) { this.status = status; }

public String getMessage() { return message; }

public void setMessage(String message) { this.message = message; }

public Object getData() { return data; }

public void setData(Object data) { this.data = data; }

}

4. 实现ServletOutputStream 指定的扩展

public class FilterServletOutputStream extends ServletOutputStream {

DataOutputStream output;

public FilterServletOutputStream(OutputStream output) {

this.output = new DataOutputStream(output);

}

@Override

public void write(int arg0) throws IOException {

output.write(arg0);

}

@Override

public void write(byte[] arg0, int arg1, int arg2) throws IOException {

output.write(arg0, arg1, arg2);

}

@Override

public void write(byte[] arg0) throws IOException {

output.write(arg0);

}

}

5. 替换原来的输出

public class ResponseWrapper extends HttpServletResponseWrapper {

ByteArrayOutputStream output;

FilterServletOutputStream filterOutput;

HttpResponseStatus status = HttpResponseStatus.OK;

public ResponseWrapper(HttpServletResponse response) {

super(response);

output = new ByteArrayOutputStream();

}

@Override

public ServletOutputStream getOutputStream() throws IOException {

if (filterOutput == null) {

filterOutput = new FilterServletOutputStream(output);

}

return filterOutput;

}

public byte[] getDataStream() {

return output.toByteArray();

}

}

文章应用: http://stackoverflow.com/questions/25020331/spring-mvc-how-to-modify-json-response-sent-from-controller