Springboot 修改post请求接口入参或重新赋值

前言

很久之前写过一篇就是自动填充接口参数的，利用的 HandlerMethodArgumentResolver 自定义注解

Springboot Controller接口默认自动填充业务实体参数值_springboot设置入参默认值-CSDN博客

现在这一篇也差不多，达到的目的就是重新去给post请求的参数赋值、修改啥的。

不多说，开始。

正文

首先知道一点，post请求的参数，一旦取出来就没了，因为是流数据。

所以老样子，我们写多一个HttpServletRequestWrapper ：

BodyReaderHttpServletRequestWrapper

java 复制代码

import org.apache.commons.lang3.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.Enumeration;
import java.util.Map;
import java.util.Vector;

/**
 * @Author : JCccc
 * @CreateTime : 2020/3/27
 * @Description :
 **/
public class BodyReaderHttpServletRequestWrapper extends HttpServletRequestWrapper {

    private final byte[] body;

    /**
     * 所有参数的集合
     */
    private Map<String, String[]> parameterMap;


    public BodyReaderHttpServletRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        BufferedReader reader = request.getReader();
        body = readBytes(reader);
        parameterMap = request.getParameterMap();
    }


    @Override
    public BufferedReader getReader() throws IOException {

        ServletInputStream inputStream = getInputStream();

        if (null == inputStream) {
            return null;
        }

        return new BufferedReader(new InputStreamReader(inputStream));
    }

    @Override
    public Enumeration<String> getParameterNames() {
        Vector<String> vector = new Vector<>(parameterMap.keySet());
        return vector.elements();
    }

    @Override
    public ServletInputStream getInputStream() throws IOException {

        if (body == null) {
            return null;
        }

        final ByteArrayInputStream bais = new ByteArrayInputStream(body);
        return new ServletInputStream() {

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

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

            @Override
            public void setReadListener(ReadListener listener) {

            }

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

    /**
     * 通过BufferedReader和字符编码集转换成byte数组
     *
     * @param br
     * @return
     * @throws IOException
     */
    private byte[] readBytes(BufferedReader br) throws IOException {
        String str;
        StringBuilder retStr = new StringBuilder();
        while ((str = br.readLine()) != null) {
            retStr.append(str);
        }
        if (StringUtils.isNotBlank(retStr.toString())) {
            return retStr.toString().getBytes(StandardCharsets.UTF_8);
        }
        return null;
    }
}

然后是我们这一期的核心，

DefaultDataFillHandlerMethodArgumentResolver

java 复制代码

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.speediance.admin.auth.ShiroUtils;
import com.speediance.admin.dto.req.UserDefaultDataFill;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;

import javax.servlet.http.HttpServletRequest;
import java.io.BufferedReader;
import java.util.Date;
import java.util.Objects;

@Component
public class DefaultDataFillHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.hasParameterAnnotation(UserDefaultDataFill.class);
    }

    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
                                  NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
        HttpServletRequest request = webRequest.getNativeRequest( HttpServletRequest.class );
        BodyReaderHttpServletRequestWrapper myRequestWrapper = new BodyReaderHttpServletRequestWrapper((HttpServletRequest) request);
        // 从Request的包装类中读取数据
        BufferedReader reader = myRequestWrapper.getReader();
        StringBuilder sb = new StringBuilder();
        String line;
        while ((line = reader.readLine()) != null) {
            sb.append(line);
        }
        reader.close();
        JSONObject jsonObject = JSON.parseObject(sb.toString());
        Object bean = BeanUtils.instantiateClass(parameter.getParameterType());
        BeanWrapper beanWrapper = new BeanWrapperImpl(bean);
        //重新赋值
        for (String key : jsonObject.keySet()) {
            beanWrapper.setPropertyValue(key,jsonObject.get(key));
        }
        Long userId = //比如从数据库查出来 或者从token解析出来;
   
 
        //举例子给如入参自动填充 更新操作人
        beanWrapper.setPropertyValue("updateUserId", userId);
      
        return bean;
    }


}

然后就是重写一个自定义注解，相当于需要填充数据或者进入到参数修改，我们采用它标注：

复制代码

UserDefaultDataFill

java 复制代码

import java.lang.annotation.*;


@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface UserDefaultDataFill {

}

然后就OK了，看看怎么用：

比如说一个更新接口，我们想默认填充上入参里面的修改用户ID （简单举例，其余业务要修改值，赋值自己套用就可以）

然后可以看到我们的参数解析器里面的代码 (其实就是复制流拿出参数，修改完变成当前接口的bean)：

OK，就到这。