getReader() has already been called for this request

原因：getReader() 是流只能读一次，读了就变成-1 ，getInputStream()也一样

解决原理装饰模式：

继承HttpServletRequestWrapper重写getInputStream()和getReader() 然后用Filter 把继承了HttpServletRequestWrapper往下传，在这一线程中需要用getInputStream()/getReader()都去新的类中取，下面是代码

1工具类：

private static final int BUFFER_SIZE = 1024 * 8;


public static String read(HttpServletRequest request) throws IOException {
    BufferedReader bufferedReader = request.getReader();
    StringWriter writer = new StringWriter();
    write(bufferedReader,writer);
    return writer.getBuffer().toString();
}

public static long write(Reader reader,Writer writer) throws IOException {
    return write(reader, writer, BUFFER_SIZE);
}

public static long write(Reader reader, Writer writer, int bufferSize) throws IOException
{
    int read;
    long total = 0;
    char[] buf = new char[bufferSize];
    while( ( read = reader.read(buf) ) != -1 ) {
        writer.write(buf, 0, read);
        total += read;
    }
    return total;
}

2：继承HttpServletRequestWrapper 重写

public class MyRequestWrapper extends HttpServletRequestWrapper {
    private final String body;


    public MyRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        this.body = GeneralUtlis.read(request);
    }

    public String getBody() {
        return body;
    }



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

            @Override
            public boolean isFinished() {
                return false;
            }

            @Override
            public boolean isReady() {
                return false;
            }

            @Override
            public void setReadListener(ReadListener readListener) {

            }

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

    @Override
    public BufferedReader getReader(){
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }

}

3过滤器：（注意

@Order(GlobalConstant.PRIORITY)          这是SPRING 执行优先级，（极限情况下可设置0）就这个地方吃亏搞了一天

@Component
@Order(GlobalConstant.PRIORITY)
public class MyFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        //TODO something
    }

    @Override
    public void destroy() {
        //TODO something
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        //取Body数据
        MyRequestWrapper requestWrapper = new MyRequestWrapper(request);
        filterChain.doFilter(requestWrapper != null ? requestWrapper :request,servletResponse);

    }

getReader() has already been called for this request

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