NIFI自定义开发API-HTTP分页功能

转载请注明地址： https://blog.csdn.net/u011291276/article/details/107213758

1、摘要

NIFI自定义开发搭建配置请参考：https://blog.csdn.net/u011291276/article/details/107211923

此文档目的为：在NIFI ETL中开发自定义HTTP分页查询，通过接口响应回的总条数和总页数，
生成多个分页查询的API接口地址，然后逐一进行请求获取响应信息；
HTTP分页查询一般为POST查询，此流程第二个组件同时也配置GET请求的分页查询；

2、最终结果展示

HTTP分页查询的流程逻辑为：第一次查询，获取接口响应的总条数；本地封装分页查询的多个URL；多个URL逐一查询获取每页数据；

核心插件及流程如下：

NIFI自定义开发API-HTTP分页功能

下面将逐个说明这三个组件，并直接贴上源代码。

3、组件1—— LeachHttpInvoke

LeachHttpInvoke组件在运行时，仅请求一条数据，目的只为获取接口响应的总条数或总页数；
基本参数大家都能看懂，其中body体和header头的格式都是对象字符串；
ReqMsg PassDown ：参数有两个值，
	false：不走分页查询，直接返回响应结果。此目的为不使用分页查询时使用，不过正常情况下，
		不使用分页查询时可以使用NIFI自带的组件InvokeHTTP请求；
	true：开始走分页查询，此组件在返回数据时，参数格式会有变化；

NIFI自定义开发API-HTTP分页功能

源码：

package com.leach.nifi.processor;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import com.leach.nifi.common.HttpRequestClient;
import org.apache.commons.io.IOUtils;
import org.apache.nifi.annotation.behavior.InputRequirement;
import org.apache.nifi.annotation.behavior.SupportsBatching;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.expression.ExpressionLanguageScope;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.flowfile.attributes.CoreAttributes;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.AbstractProcessor;
import org.apache.nifi.processor.ProcessContext;
import org.apache.nifi.processor.ProcessSession;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.processor.exception.ProcessException;
import org.apache.nifi.processor.io.OutputStreamCallback;
import org.apache.nifi.processor.io.StreamCallback;
import org.apache.nifi.processor.util.StandardValidators;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;
import org.springframework.http.MediaType;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.*;

/**
* @title   自定义HTTP 增加请求体输入框
* @author   xiaobin.wang
* @create   2020/01/08
*/

@SupportsBatching
@Tags({"leach","http", "https", "rest", "client"})
@InputRequirement(InputRequirement.Requirement.INPUT_ALLOWED)
@CapabilityDescription("HTTP RESTFulApi请求。支持分页查询操作(连接LeachHttpPagingHandle-LeachHttpPagingRequest）")
public class LeachHttpInvoke extends AbstractProcessor {

    public static final String DEFAULT_CONTENT_TYPE = "application/json";

    private static final Map<String, String> excludedHeaders = new HashMap<String, String>();

    private static final DateTimeFormatter DATE_FORMAT = DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss").withLocale(Locale.SIMPLIFIED_CHINESE).withZoneUTC();

    // properties
    public static final PropertyDescriptor PROP_METHOD = new PropertyDescriptor.Builder()
            .name("HTTP Method")
            .description("HTTP request method (GET, POST)")
            .required(true)
            .defaultValue("GET")
            .allowableValues("POST","GET")
            .build();

    public static final PropertyDescriptor PROP_URL = new PropertyDescriptor.Builder()
            .name("Remote URL")
            .description("Remote URL which will be connected to, including scheme, host, port, path.")
            .required(true)
            .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
            .addValidator(StandardValidators.URL_VALIDATOR)
            .build();
    public static final PropertyDescriptor REQUEST_BODY = new PropertyDescriptor.Builder()
            .name("Request Body")
            .description("请求体参数 JSON字符串格式对象 ｛\"key\":\"value\"｝")
            .required(false)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .build();
    public static final PropertyDescriptor CONTENT_TYPE = new PropertyDescriptor.Builder()
            .name("Content Type")
            .description("Content Type(GET请求时无效)")
            .required(true)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .allowableValues("raw","x-www-form-urlencoded","form-data")
            .defaultValue("raw")
            .build();
    public static final PropertyDescriptor REQUEST_HEADER = new PropertyDescriptor.Builder()
            .name("Request Header")
            .description("请求头 JSON字符串格式对象 ｛\"key\":\"value\"｝。此处不需要配置content-type。")
            .required(false)
            .expressionLanguageSupported(ExpressionLanguageScope.VARIABLE_REGISTRY)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .build();

    public static final PropertyDescriptor PROP_PASS_DOWN = new PropertyDescriptor.Builder()
            .name("ReqMsg PassDown")
            .description("是否允许请求信息向下传递。分页查询需向下传递（{\"url\":\"\",\"header\":{},\"body\":{}）")
            .required(false)
            .defaultValue("false")
            .allowableValues("true", "false")
            .build();

    public static final List<PropertyDescriptor> PROPERTIES = Collections.unmodifiableList(Arrays.asList(
            PROP_METHOD,
            PROP_URL,
            REQUEST_BODY,
            REQUEST_HEADER,
            CONTENT_TYPE,
            PROP_PASS_DOWN));

    public static final Relationship FAILURE = new Relationship.Builder()
            .name("failure")
            .description("执行异常或失败，返回此标志")
            .build();
    public static final Relationship SUCCESS = new Relationship.Builder()
            .name("success")
            .description("RESTFul Api执行成功，返回此URL响应的内容信息。" +
                    "当ReqMsg PassDown选择true时，将返回带有请求参数的封装体{\"reqMsg\":Object,\"respMsg\":Object}。" +
                    "当值为false时，直接返回url请求结果Object")
            .build();

    public static final Set<Relationship> RELATIONSHIPS = Collections.unmodifiableSet(new HashSet<>(Arrays.asList(
            FAILURE,SUCCESS)));

    @Override
    public Set<Relationship> getRelationships() {
        return this.RELATIONSHIPS;
    }

    @Override
    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return PROPERTIES;
    }


    @Override
    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
        final ComponentLog logger =getLogger();
        FlowFile requestFlowFile = session.get();
        if(requestFlowFile==null){
            requestFlowFile=session.create();
        }
        final String request_url = context.getProperty(PROP_URL).getValue();
        final String request_method=context.getProperty(PROP_METHOD).getValue();
        final String content_type=context.getProperty(CONTENT_TYPE).getValue();
        final boolean isPassDown=context.getProperty(PROP_PASS_DOWN).asBoolean();
        //请求头
        final String request_header = context.getProperty(REQUEST_HEADER).getValue();

        //请求参数body处理开始
        String reqMsg="";
        //获取输入参数
        if(context.getProperty(REQUEST_BODY).isSet()){
            final String request_body = context.getProperty(REQUEST_BODY).getValue();
            reqMsg=request_body;
        }else{
            final String[] req_bodys = new String[1];
            //获取请求体
            requestFlowFile = session.write(requestFlowFile, new StreamCallback() {
                @Override
                public void process(InputStream rcdIn, OutputStream rcdOut) throws IOException {
                    req_bodys[0] = IOUtils.toString(rcdIn,"utf-8");
                }
            });
            reqMsg=req_bodys[0];
        }

        try {
            String respMsg=null;
            //发送HTTP请求
            if("POST".equals(request_method)){
                respMsg= HttpRequestClient.post(request_url,reqMsg,content_type,request_header);
            }
            if("GET".equals(request_method)){
                respMsg= HttpRequestClient.get(request_url);
            }
            logger.debug("URL:"+request_url+"\n响应信息："+respMsg);
            //移除上游下来的数据
            session.remove(requestFlowFile);
            //创建响应
            FlowFile responseFlowFile = session.create();
            //向下传递则封装信息体
            if (isPassDown) {
                //将请求URL和参数、请求头封装进map，供后续分页功能使用，或其需要的地方
                Map<String,String> request=new HashMap<String,String>();
                request.put("url",request_url);
                request.put("header",request_header);
                request.put("reqMsg",reqMsg);
                request.put("respMsg",respMsg);
                request.put("method",request_method);

                String requestMsg=JSONObject.toJSONString(request);
                responseFlowFile = session.write(responseFlowFile, new OutputStreamCallback() {
                    @Override
                    public void process(final OutputStream out) throws IOException {
                        out.write(requestMsg.getBytes("UTF-8"));
                    }
                });
            }else{
                //响应信息
                final byte[] respByte =respMsg.getBytes("utf-8");
                if (respByte.length > 0) {
                    responseFlowFile = session.write(responseFlowFile, new OutputStreamCallback() {
                        @Override
                        public void process(final OutputStream out) throws IOException {
                            out.write(respByte);
                        }
                    });
                }
            }
            if (responseFlowFile != null) {
                session.getProvenanceReporter().fetch(responseFlowFile, request_url);
            }
            //接口响应信息
            responseFlowFile = session.putAttribute(responseFlowFile, CoreAttributes.MIME_TYPE.key(), "application/json");
            //直接返回响应结果
            session.transfer(responseFlowFile, SUCCESS);
        } catch (Exception e) {
            // penalize or yield
            logger.error("Leach HTTP 异常：",e);
            try {
                if (requestFlowFile != null) {
                    session.remove(requestFlowFile);
                }
            } catch (final Exception e1) {
                logger.error("Could not cleanup response flowfile due to exception: {}", new Object[]{e1}, e1);
            }
            logger.error("LeachHttpInvoke 执行异常：{}",e);
            FlowFile flowFile=session.create();
            final String errMsg="LeachHttpInvoke 执行异常："+e.getMessage();
            flowFile=session.write(flowFile,out -> out.write(errMsg.getBytes("utf-8")));
            session.transfer(flowFile, FAILURE);
        }
    }
}

4、组件2——LeachHttpPagingHandle

LeachHttpPagingHandle 此组件 为分页查询的核心，即根据收到的总条数、总页数和自定义配置的分页参数，
	进行组装分页URL，然后返回多个URL，每个URL单独返回，在队列中也是有多个queued数据；
考虑到分页参数可能存在于嵌套JSON中，所以获取分页参数属性名可以使用“:”来进行提取；

Request Paging Size AttrName ：请求中每页数据量的属性名，若存在于嵌套中，则使用英文“:”号分割(POST请求必填)。
	例：key:key1:key2 ；
Request Paging Index AttrName ： 请求中分页页码的属性名，若存在于嵌套中，则使用英文“:”号分割(POST请求必填)。
	例：key:key1:key2 ；
Response DataSize AttrName ： 响应内容中总条数的属性名，若提取嵌套中的属性名，则使用英文“:”号分割。
	例：key:key1:key2 ；
Total Page Size ： 总分页页码数。若不填"Response  DataSize AttrName"，则将此属性值设置的页码数作为总页数进行分页查询；
Get Paging URL ： GET请求需循环分页时使用，页码大小实际参数使用\"${size}\"替换，分页页码实际参数使用\"${index}\"替换。	
	处理时会根据响应计算出的总页数依次替换这两个变量，返回多个分页后的URL。
	例：http://127.0.0.1:8080/get?attr1=参数1&pageSize=${size}&pageIndex=${index} 。
	此参数主要为GET请求分页使用。

NIFI自定义开发API-HTTP分页功能

源码：

package com.leach.nifi.processor;

import com.alibaba.fastjson.JSONObject;
import com.leach.nifi.common.LeachCommon;
import org.apache.commons.io.IOUtils;
import org.apache.nifi.annotation.behavior.InputRequirement;
import org.apache.nifi.annotation.behavior.SideEffectFree;
import org.apache.nifi.annotation.behavior.SupportsBatching;
import org.apache.nifi.annotation.behavior.WritesAttribute;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.flowfile.attributes.CoreAttributes;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.*;
import org.apache.nifi.processor.exception.ProcessException;
import org.apache.nifi.processor.io.StreamCallback;
import org.apache.nifi.processor.util.StandardValidators;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.*;

/**
* @title    
* @author   xiaobin.wang
* @create   2020/01/02
*/
//不需要关注上下文
@SideEffectFree
//支持批量
@SupportsBatching
//用于标记这个processor的标签，可以用于搜索
@Tags({ "leach","add", "value", "avro" ,"static","param"})
// 声明，对于该processor输入是必须的
@InputRequirement(InputRequirement.Requirement.INPUT_ALLOWED)
//针对这个processor的注释
@CapabilityDescription("HTTP  RESTFulApi请求，接收的数据格式为JSON对象：{\"url\":\"String\",\"header\":\"{}\",\"reqMsg\":\"{}\",\"connectTimeout\":\"\",\"readTimeout\":\"\"}")
@WritesAttribute(attribute = "mime.type", description = "Sets the mime type to application/json")
public class LeachHttpPagingHandle extends AbstractProcessor {

    private List<PropertyDescriptor> properties;
    private Set<Relationship> relationships;

    public static final PropertyDescriptor PAGE_SIZE=new PropertyDescriptor.Builder()
            .name("Page Size")
            .required(true)
            .addValidator(StandardValidators.NUMBER_VALIDATOR)
            .defaultValue("200")
            .description("分页页码大小")
            .build();
    public static final PropertyDescriptor PAGING_SIZE_ATTR_NAME = new PropertyDescriptor.Builder()
            // 参数名，输入框前展示的内容
            .name("Request Paging Size AttrName")
            // 是否必填
            .required(false)
            // 添加过滤器
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .description("请求中每页数据量的属性名，若存在于嵌套中，则使用英文“:”号分割(POST请求必填)。例：key:key1:key2")
            // 内容添加完成后构建
            .build();
    public static final PropertyDescriptor PAGING_INDEX_ATTR_NAME = new PropertyDescriptor.Builder()
            // 参数名，输入框前展示的内容
            .name("Request Paging Index AttrName")
            // 是否必填
            .required(false)
            // 添加过滤器
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .description("请求中分页页码的属性名，若存在于嵌套中，则使用英文“:”号分割(POST请求必填)。例：key:key1:key2")
            // 内容添加完成后构建
            .build();
    public static final PropertyDescriptor DATASIZE_ATTR_NAME = new PropertyDescriptor.Builder()
            // 参数名，输入框前展示的内容
            .name("Response DataSize AttrName")
            // 是否必填
            .required(false)
            // 添加过滤器
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .description("响应内容中总条数的属性名，若提取嵌套中的属性名，则使用英文“:”号分割。例：key:key1:key2")
            // 内容添加完成后构建
            .build();

    public static final PropertyDescriptor TOTAL_PAGE_SIZE = new PropertyDescriptor.Builder()
            // 参数名，输入框前展示的内容
            .name("Total Page Size")
            // 是否必填
            .required(false)
            // 添加过滤器
            .addValidator(StandardValidators.NUMBER_VALIDATOR)
            .description("总分页页码数。若不填\"DataSize AttrName\"，则将此属性值设置的页码数作为总页数进行分页查询")
            // 内容添加完成后构建
            .build();
    public static final PropertyDescriptor GET_PAGING_URL= new PropertyDescriptor.Builder()
            // 参数名，输入框前展示的内容
            .name("Get Paging URL")
            // 是否必填
            .required(false)
            // 添加过滤器
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .description("GET请求需循环分页时使用，页码大小实际参数使用\"${size}\"替换，分页页码实际参数使用\"${index}\"替换。" +
                    "\n处理时会根据响应计算出的总页数依次替换这两个变量，返回多个分页后的URL。" +
                    "\n例：http://127.0.0.1:8080/get?attr1=参数1&pageSize=${size}&pageIndex=${index}")
            // 内容添加完成后构建
            .build();

    public static final Relationship SUCCESS = new Relationship.Builder().name("success")
            .description("API分页查询处理成功，返回数据格式为JSON对象：{\"url\":\"String\",\"header\":\"{}\",\"reqMsg\":\"{}\"}").build();

    public static final Relationship FAILURE = new Relationship.Builder().name("failure").description(
            "API分页查询处理异常或失败，返回此标志。")
            .build();

    @Override
    public void init(final ProcessorInitializationContext context) {
        ArrayList<PropertyDescriptor> properties = new ArrayList<>();
        properties.add(PAGE_SIZE);
        properties.add(PAGING_SIZE_ATTR_NAME);
        properties.add(PAGING_INDEX_ATTR_NAME);
        properties.add(DATASIZE_ATTR_NAME);
        properties.add(TOTAL_PAGE_SIZE);
        properties.add(GET_PAGING_URL);
        // 防止多线程ADD
        this.properties = Collections.unmodifiableList(properties);
        Set<Relationship> relationships = new HashSet<>();
        relationships.add(SUCCESS);
        relationships.add(FAILURE);
        // 防止多线程ADD
        this.relationships = Collections.unmodifiableSet(relationships);
    }


    @Override
    public void onTrigger(ProcessContext processContext, ProcessSession processSession) throws ProcessException {
        ComponentLog logger=getLogger();
        FlowFile flowFile = processSession.get();
        if (flowFile == null) {
            getLogger().error("FlowFile is null", new Object[] {});
            return;
        }

        //拿到请求信息，下边开始处理分页参数
        int page_size = processContext.getProperty(PAGE_SIZE).asInteger();
        int start_index = 1;
        String paging_size_attr_name = processContext.getProperty(PAGING_SIZE_ATTR_NAME).getValue();
        String paging_index_attr_name = processContext.getProperty(PAGING_INDEX_ATTR_NAME).getValue();
        String datasize_attr_name = processContext.getProperty(DATASIZE_ATTR_NAME).getValue();
        final String get_paging_uri = processContext.getProperty(GET_PAGING_URL).getValue();

        final String[] _request_str=new String[1];
        try {
            flowFile = processSession.write(flowFile, new StreamCallback() {
                @Override
                public void process(InputStream rcdIn, OutputStream rcdOut) throws IOException {
                    String json = IOUtils.toString(rcdIn,"utf-8");
                    _request_str[0]=json;
                }
            });

            //url method header reqMsg respMsg
            final String httpStr=_request_str[0];
            Map<String,String> httpMap=JSONObject.parseObject(httpStr,Map.class);
            JSONObject reqJson=JSONObject.parseObject(httpMap.get("reqMsg"),JSONObject.class);
            JSONObject respJson=JSONObject.parseObject(httpMap.get("respMsg"),JSONObject.class);
            String method=httpMap.get("method");
            //取出响应信息后，直接删除
            httpMap.remove("respMsg");

            //计算总页数
            int total_page=0;
            //判断是否填写了total_page_size
            if(processContext.getProperty(TOTAL_PAGE_SIZE).isSet()){
                //如果设置，则按照这个为总页数
                total_page = processContext.getProperty(TOTAL_PAGE_SIZE).asInteger();
            }else{
                //否则根据响应信息中返回的字段来计算总页数
                String[] attrs=datasize_attr_name.split(":");
                List<String> list=new ArrayList<>();
                Collections.addAll(list,attrs);
                //获取属性Value
                Object dataSizeStr=LeachCommon.extractAttrVal(list,respJson);
                try {
                    double data_size=Float.valueOf(String.valueOf(dataSizeStr));
                    //总条数 / 总页数  向上取整，转int
                    total_page=new Double(Math.ceil(data_size/page_size)).intValue();
                } catch (NumberFormatException e) {
                    e.printStackTrace();
                    logger.error("总数据量属性提取内容应为整数数字类型，当前内容：{}",new Object[]{String.valueOf(dataSizeStr)});
                    throw new NumberFormatException("总数据量属性提取内容应为整数数字类型，当前内容：{}"+String.valueOf(dataSizeStr));
                }
            }
            if(start_index > total_page){
                logger.error("开始查询的页码（"+start_index+"）大于总页数（"+total_page+"），不执行查询。当前每页："+page_size+"条");
                throw new Exception("开始查询的页码（"+start_index+"）大于总页数（"+total_page+"），不执行查询。当前每页："+page_size+"条");
            }
            logger.info("total_page："+total_page+",start_index:"+start_index);
            //现在有总页数、有请求信息，开始替换请求信息中的分页参数，然后封装HTTP请求到flowfile
            if("GET".equals(method)){
                //get分页替换参数
                if(get_paging_uri.indexOf(":_index") > 0){
                    for(int i=start_index;i<=total_page;i++){
                        String paging_uri=get_paging_uri
                                .replaceAll(":_index",i+"")
                                .replaceAll(":_size",page_size+"");
                        httpMap.put("url",paging_uri);

                        String pageStr=JSONObject.toJSONString(httpMap);
                        FlowFile pageFlowFile=processSession.create();
                        pageFlowFile=processSession.write(pageFlowFile,out -> out.write(pageStr.getBytes("utf-8")));
                        Map<String, String> attributes = new HashMap<>();
                        attributes.put(CoreAttributes.MIME_TYPE.key(),"application/json");
                        attributes.put("inputProcessor", this.getIdentifier());
                        attributes.put("relationship","success");
                        attributes.put("level", "INFO");

                        pageFlowFile=processSession.putAllAttributes(pageFlowFile,attributes);
                        processSession.transfer(pageFlowFile, SUCCESS);
                    }
                }else{
                    String pageStr=JSONObject.toJSONString(httpMap);
                    FlowFile pageFlowFile=processSession.create();
                    pageFlowFile=processSession.write(pageFlowFile,out -> out.write(pageStr.getBytes("utf-8")));
                    Map<String, String> attributes = new HashMap<>();
                    attributes.put(CoreAttributes.MIME_TYPE.key(),"application/json");
                    attributes.put("inputProcessor", this.getIdentifier());
                    attributes.put("relationship","success");
                    attributes.put("level", "INFO");

                    pageFlowFile=processSession.putAllAttributes(pageFlowFile,attributes);
                    processSession.transfer(pageFlowFile, SUCCESS);
                }
            }else{
                //POST方式替换变量
                List<String> attrList =new ArrayList<String>();
                Collections.addAll(attrList,paging_size_attr_name.split(":"));
                //替换分页size
                reqJson=LeachCommon.replaceAttr(attrList,reqJson,page_size+"");
                String[] indexAttrs=paging_index_attr_name.split(":");
                //开始替换当前页下标
                for(int i=start_index;i<=total_page;i++){
                    attrList.clear();
                    //将数组添加到集合中，方便移除元素递归操作
                    Collections.addAll(attrList,indexAttrs);
                    //替换当前页下标
                    reqJson= LeachCommon.replaceAttr(attrList,reqJson,i+"");
                    //替换http请求包中的请求信息，保留url、header等信息
                    httpMap.put("reqMsg",JSONObject.toJSONString(reqJson));

                    //将每一页的httpMap封装进flowfile中
                    String pageStr=JSONObject.toJSONString(httpMap);
                    FlowFile pageFlowFile=processSession.create();
                    pageFlowFile=processSession.write(pageFlowFile,out -> out.write(pageStr.getBytes("utf-8")));
                    Map<String, String> attributes = new HashMap<>();
                    attributes.put(CoreAttributes.MIME_TYPE.key(),"application/json");
                    attributes.put("inputProcessor", this.getIdentifier());
                    attributes.put("relationship","success");
                    attributes.put("level", "INFO");

                    pageFlowFile=processSession.putAllAttributes(pageFlowFile,attributes);
                    processSession.transfer(pageFlowFile, SUCCESS);
                }
            }
            //移除
            processSession.remove(flowFile);
        } catch (final Exception pe) {
            logger.error("API分页处理异常：{}",pe);
            if(flowFile!=null){
                try {
                    processSession.remove(flowFile);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            flowFile=processSession.create();
            final String errMsg="API分页处理异常："+pe.getMessage();
            flowFile=processSession.write(flowFile,out -> out.write(errMsg.getBytes("utf-8")));
            flowFile = processSession.putAttribute(flowFile, CoreAttributes.MIME_TYPE.key(), "application/json");
            flowFile = processSession.putAttribute(flowFile, "inputProcessor", this.getIdentifier());
            flowFile = processSession.putAttribute(flowFile, "relationship", "failure");
            flowFile = processSession.putAttribute(flowFile, "level", "ERROR");
            processSession.transfer(flowFile, FAILURE);
        }
    }

    @Override
    public Set<Relationship> getRelationships() {
        return relationships;
    }

    @Override
    public List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return properties;
    }
}

5、组件3——LeachHttpPagingRequest

LeachHttpPagingRequest 组件目的为将收到的URL发起http请求 ；此组件比较简单，配置如下；

NIFI自定义开发API-HTTP分页功能

源码：

package com.leach.nifi.processor;

import com.alibaba.fastjson.JSONObject;
import com.leach.nifi.common.HttpRequestClient;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.nifi.annotation.behavior.InputRequirement;
import org.apache.nifi.annotation.behavior.SupportsBatching;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.flowfile.attributes.CoreAttributes;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.AbstractProcessor;
import org.apache.nifi.processor.ProcessContext;
import org.apache.nifi.processor.ProcessSession;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.processor.exception.ProcessException;
import org.apache.nifi.processor.io.StreamCallback;
import org.apache.nifi.processor.util.StandardValidators;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.*;

/**
* @title   自定义HTTP HTTP请求直接发送
* @author   xiaobin.wang
* @create   2020/05/07
*/

@SupportsBatching
@Tags({"leach","http","api", "post","get"})
@InputRequirement(InputRequirement.Requirement.INPUT_ALLOWED)
@CapabilityDescription("根据传入或输入的http对象，直接进行发送并返回json信息。" +
        "传入http对象格式为JSON对象或JSON集合：[{\"url\":\"String\",\"header\":\"{}\",\"reqMsg\":\"{}\",\"connectTimeout\":\"\",\"readTimeout\":\"\"}]")
public class LeachHttpPagingRequest extends AbstractProcessor {

    // properties
    public static final PropertyDescriptor PROP_METHOD = new PropertyDescriptor.Builder()
            .name("HTTP Method")
            .description("HTTP request method (GET, POST)")
            .required(true)
            .defaultValue("GET")
            .allowableValues("POST","GET")
            .build();
    // properties
    public static final PropertyDescriptor HTTP_MSG = new PropertyDescriptor.Builder()
            .name("HTTP Msg")
            .description("输入数据格式为JSON对象或JSON集合：[{\"url\":\"String\",\"header\":\"{}\",\"reqMsg\":\"{}\"}]")
            .required(false)
            .build();
    public static final PropertyDescriptor CONTENT_TYPE = new PropertyDescriptor.Builder()
            .name("Content Type")
            .description("Content Type(GET请求时无效)")
            .required(true)
            .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
            .allowableValues("raw","x-www-form-urlencoded","form-data")
            .defaultValue("raw")
            .build();

    public static final List<PropertyDescriptor> PROPERTIES = Collections.unmodifiableList(Arrays.asList(
            PROP_METHOD,CONTENT_TYPE,HTTP_MSG));

    public static final Relationship FAILURE = new Relationship.Builder()
            .name("failure")
            .description("执行异常或失败，返回此标志")
            .build();
    public static final Relationship SUCCESS = new Relationship.Builder()
            .name("success")
            .description("API查询成功，返回接口响应的JSON信息")
            .build();

    public static final Set<Relationship> RELATIONSHIPS = Collections.unmodifiableSet(new HashSet<>(Arrays.asList(
            FAILURE,SUCCESS)));

    @Override
    public Set<Relationship> getRelationships() {
        return this.RELATIONSHIPS;
    }

    @Override
    protected List<PropertyDescriptor> getSupportedPropertyDescriptors() {
        return PROPERTIES;
    }

    @Override
    public void onTrigger(ProcessContext context, ProcessSession session) throws ProcessException {
        final ComponentLog logger =getLogger();

        FlowFile requestFlowFile = session.get();
        if(requestFlowFile==null){
            requestFlowFile=session.create();
        }
        final String http_msg = context.getProperty(HTTP_MSG).getValue();
        final String content_type = context.getProperty(CONTENT_TYPE).getValue();
        final String http_method = context.getProperty(PROP_METHOD).getValue();

        final String[] req_bodys = new String[1];
        //获取请求Flowfile
        requestFlowFile = session.write(requestFlowFile, new StreamCallback() {
            @Override
            public void process(InputStream rcdIn, OutputStream rcdOut) throws IOException {
                req_bodys[0] = IOUtils.toString(rcdIn,"utf-8");
            }
        });
        String httpMsg=req_bodys[0];

        //如果flowfile传入是空的，且输入参数有数据，则使用输入数据进行查询
        if(StringUtils.isEmpty(httpMsg) && context.getProperty(http_msg).isSet()){
            httpMsg = context.getProperty(http_msg).getValue();
        }
        List<Map<String,String>> httpMapList=new ArrayList<Map<String,String>>();
        if(httpMsg.trim().startsWith("[")){
            httpMapList=JSONObject.parseObject(httpMsg,List.class);
        }else{
            Map<String,String> map=JSONObject.parseObject(httpMsg,Map.class);
            httpMapList.add(map);
        }
        try {
            //响应集合
            List<FlowFile> respFlowFiles=new ArrayList<FlowFile>();
            for(Map<String,String> httpMap : httpMapList){
                logger.debug("请求URL:{}\n请求header:{}\n请求Req:{}",new Object[]{httpMap.get("url"),httpMap.get("header"),httpMap.get("reqMsg")});
                //发送HTTP请求
                String respMsg=null;
                //发送HTTP请求
                if("POST".equals(http_method)){
                    respMsg= HttpRequestClient.post(httpMap.get("url"),httpMap.get("reqMsg"),content_type,httpMap.get("header"));
                }
                if("GET".equals(http_method)){
                    respMsg= HttpRequestClient.get(httpMap.get("url"));
                }
                respMsg=respMsg!=null?respMsg:"";
                //使用完移除 请求体里面的内容
                session.remove(requestFlowFile);
                //创建响应
                FlowFile responseFlowFile = session.create();
                //响应信息
                final byte[] respData =respMsg.getBytes("utf-8");
                if (respData.length > 0) {
                    responseFlowFile = session.write(responseFlowFile, out ->out.write(respData));
                }
                if (responseFlowFile != null) {
                    session.getProvenanceReporter().fetch(responseFlowFile, httpMap.get("url"));
                }

                Map<String, String> attributes = new HashMap<>();
                attributes.put(CoreAttributes.MIME_TYPE.key(),"application/json");
                attributes.put("inputProcessor", this.getIdentifier());
                attributes.put("relationship","success");
                attributes.put("level", "INFO");

                responseFlowFile=session.putAllAttributes(responseFlowFile,attributes);
                respFlowFiles.add(responseFlowFile);
            }
            //接口响应信息
            session.transfer(respFlowFiles,SUCCESS);
        } catch (Exception e) {
            try {
                if (requestFlowFile != null) {
                    session.remove(requestFlowFile);
                }
            } catch (final Exception e1) {
                logger.error("Could not cleanup response flowfile due to exception: {}", new Object[]{e1}, e1);
            }
            logger.error("LeachHttpPagingRequest API请求异常：{}",e);
            FlowFile flowFile=session.create();
            final String errMsg="LeachHttpPagingRequest API请求异常："+e.getMessage();
            flowFile=session.write(flowFile,out -> out.write(errMsg.getBytes("utf-8")));
            session.transfer(flowFile, FAILURE);
        }
    }
}

6、总结

此流程为个人开发，里面的逻辑基本都有注释，上下的组件格式也是经过单独处理进行发送和接收。
各位同学在开发时也可以根据个人需求进行逻辑修改。

NIFI自定义开发API-HTTP分页功能

1、摘要

2、最终结果展示

3、组件1—— LeachHttpInvoke

4、组件2——LeachHttpPagingHandle

5、组件3——LeachHttpPagingRequest

6、总结

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