Jasper Reports：从 post 休息服务获取 JSON 数据

Question

我正在尝试从休息服务中获取 JSON 数据。我知道这对于 GET 服务来说非常简单，您只需提供 URI，Jasper studio 就可以提取数据，但我想为 post 休息服务执行此操作，该服务也会消耗一些 JSON 输入.

工作流程类似于：

在请求中发送用户 ID header 和请求中的一些 JSON 参数 body.
获取 JSON 数据作为输出。
使用 JSON 数据构建报告。

我是 Jasper 的新手，我正在使用 Jasper server 6 和 Japser Studio 6，但我找不到任何文档来做这样的事情。

如果有人能为此指出正确的方向，我将不胜感激。

我能找到的关闭的东西是 this link。从那里我知道我可以创建一个构造函数，该构造函数将从其余服务中获取数据，但是我如何将其提供给报告？另请注意，此处检索的 JSON object 有点复杂，至少有 2 个包含任意数量项目的列表。

编辑：

好的，我的自定义适配器是这样的：

package CustomDataAdapter;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.json.JSONObject;

public class SearchAdapter implements JRDataSource {
/**
 * This will hold the JSON returned by generic search service
 */
private JSONObject json = null;

/**
 * Will create the object with data retrieved from service.
 */
public SearchAdapter() {
    String url = "[URL is here]";
    String request = "{searchType: \"TEST\", searchTxt: \"TEST\"}";

    // Setting up post client and request.
    HttpClient client = HttpClientBuilder.create().build();
    HttpPost post = new HttpPost(url);
    HttpResponse response = null;

    post.setHeader("userId", "1000");
    post.setHeader("Content-Type", "application/json");

    // Setting up Request payload
    HttpEntity entity = null;
    try {
        entity = new StringEntity(request);
        post.setEntity(entity);

        // do post
        response = client.execute(post);
    } catch (ClientProtocolException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    // Reading Server Response
    try {
        int statusCode = response.getStatusLine().getStatusCode();
        if (statusCode != 200) {
            throw new Exception("Search Failed");
        }

        BufferedReader in = new BufferedReader(new InputStreamReader(
                response.getEntity().getContent()));
        String inputLine;
        StringBuffer resp = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            resp.append(inputLine);
        }

        in.close();

        this.json = new JSONObject(resp.toString());
    } catch (NullPointerException e) {
        e.printStackTrace();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

}

/*
 * (non-Javadoc)
 * 
 * @see
 * net.sf.jasperreports.engine.JRDataSource#getFieldValue(net.sf.jasperreports
 * .engine.JRField)
 */
public Object getFieldValue(JRField field) throws JRException {
    // TODO Auto-generated method
    // stubhttp://community-static.jaspersoft.com/sites/default/files/images/0.png
    return this.json;
}

/*
 * (non-Javadoc)
 * 
 * @see net.sf.jasperreports.engine.JRDataSource#next()
 */
public boolean next() throws JRException {
    return (this.json != null);
}

/**
 * Return an instance of the class that implements the custom data adapter.
 */
public static JRDataSource getDataSource() {
    return new SearchAdapter();
}

}

我能够在 Jasper Studio 中创建一个适配器和测试连接功能 returns 正确，但我无法让它读取 JSON 和 [=41= 中的任何字段] 那个报告。我只得到一份空白文件。仅供参考，JSON 类似于：

{
"key": "value",
"key": "value",
"key": [list],
"key": [list]
}

Answer 1

好吧，我现在觉得自己很蠢，但解决方案很简单。原来你不能只是 return 一个 JSON 对象。您需要 return 字段并在报告中手动添加字段。

出于记录目的，我的最终代码如下所示：

package CustomDataAdapter;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.json.JSONException;
import org.json.JSONObject;

public class SearchAdapter implements JRDataSource {

    /**
     * This will hold the JSON returned by generic search service
     */
    private JSONObject json = null;

    /**
     * Ensures that we infinitely calling the service.
     */
    private boolean flag = false;
    /**
     * Will create the object with data retrieved from service.
     */
    private void setJson() {
        String url = "[URL is here]";
        String request = "{\"searchType\": \"Test\", \"searchTxt\": \"Test\"}";

        // Setting up post client and request.
        HttpClient client = HttpClientBuilder.create().build();
        HttpPost post = new HttpPost(url);
        HttpResponse response = null;

        post.setHeader("userId", "1000");
        post.setHeader("Content-Type", "application/json");

        // Setting up Request payload
        StringEntity entity = null;
        try {
            entity = new StringEntity(request);
            post.setEntity(entity);

            // do post
            response = client.execute(post);
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        // Reading Server Response
        try {
            int statusCode = response.getStatusLine().getStatusCode();
            if (statusCode != 200) {
                // Thrown Exception in case things go wrong
                BufferedReader in = new BufferedReader(new InputStreamReader(
                        response.getEntity().getContent()));
                String inputLine;
                StringBuffer resp = new StringBuffer();
                while ((inputLine = in.readLine()) != null) {
                    resp.append(inputLine);
                }

                in.close();

                String ex = "Search Failed. Status Code: " + statusCode;
                ex += "\n Error: " + resp.toString();
                throw new Exception(ex);
            }

            BufferedReader in = new BufferedReader(new InputStreamReader(
                    response.getEntity().getContent()));
            String inputLine;
            StringBuffer resp = new StringBuffer();
            while ((inputLine = in.readLine()) != null) {
                resp.append(inputLine);
            }

            in.close();

            this.json = new JSONObject(resp.toString());
        } catch (NullPointerException e) {
            e.printStackTrace();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * net.sf.jasperreports.engine.JRDataSource#getFieldValue(net.sf.jasperreports
     * .engine.JRField)
     */
    @Override
    public Object getFieldValue(JRField field) throws JRException {
        // TODO Auto-generated method
        // stubhttp://community-static.jaspersoft.com/sites/default/files/images/0.png
        try {
            return this.json.get(field.getName());
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return null;
    }

    /*
     * (non-Javadoc)
     * 
     * @see net.sf.jasperreports.engine.JRDataSource#next()
     */
    @Override
    public boolean next() throws JRException {
        if (this.json != null && !flag) {
            flag = true;
            return true;
        } else {
            return false;
        }
    }

    /**
     * Return an instance of the class that implements the custom data adapter.
     */
    public static JRDataSource getDataSource() {
        SearchAdapter adapter = new SearchAdapter();
        adapter.setJson();
        return adapter;
    }

}

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