HttpServletRequestWrapper改写http请求body

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package cn.xs.qishi.open.api.filter;
 
import cn.xs.ambi.bas.util.StringUtils;
 
import javax.servlet.ReadListener;
import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.*;
 
/**
 * @author liuxn
 * @date 2022/5/24
 */
public class RequestWrapper extends HttpServletRequestWrapper {
    private Map<String, String> headerMap = new HashMap<>();
    // 重新赋值的body数据
    private String body;
    public RequestWrapper(HttpServletRequest request) {
        super(request);
    }
 
    public void addHeader(String name, String value) {
        headerMap.put(name, value);
    }
    public void setBody(String body) {
        this.body = body;
    }
 
    @Override
    public int getContentLength() {
        return this.body.getBytes(StandardCharsets.UTF_8).length;
    }
 
    @Override
    public long getContentLengthLong() {
        return this.body.getBytes(StandardCharsets.UTF_8).length;
    }
 
 
    @Override
    public ServletInputStream getInputStream() throws IOException {
        if (StringUtils.isBlank(body)) {
            body = "";
        }
        // 必须指定utf-8编码，否则json请求数据中如果包含中文，会出现异常
        final ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(body.getBytes(StandardCharsets.UTF_8));
        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() throws IOException {
                return byteArrayInputStream.read();
            }
        };
    }
 
    @Override
    public BufferedReader getReader() throws IOException {
        return new BufferedReader(new InputStreamReader(this.getInputStream()));
    }
 
 
    @Override
    public String getHeader(String name) {
        String headerValue = super.getHeader(name);
        if (headerMap.containsKey(name)) {
            headerValue = headerMap.get(name);
        }
        return headerValue;
    }
 
    @Override
    public Enumeration<String> getHeaderNames() {
        List<String> names = Collections.list(super.getHeaderNames());
        names.addAll(headerMap.keySet());
        return Collections.enumeration(names);
    }
 
    @Override
    public Enumeration<String> getHeaders(String name) {
        List<String> values = Collections.list(super.getHeaders(name));
        if (headerMap.containsKey(name)) {
            values.add(headerMap.get(name));
        }
        return Collections.enumeration(values);
    }
}

问题记录：- Content-length different from byte array length! cl=97, array=117

问题点：getContentLength（）、getContentLengthLong（）这两个方法取值不正确

正确写法：

@Override
   public int getContentLength() {
       return this.body.getBytes(StandardCharsets.UTF_8).length;
   }
 
   @Override
   public long getContentLengthLong() {
       return this.body.getBytes(StandardCharsets.UTF_8).length;
   }