帆软报表自定义函数-取json数据

谁践踏了优雅 2023-07-08 09:23 43阅读 0赞

帆软报表支持，写 Java 代码自定义函数，完成各种逻辑的取数。

**最近遇到一个需求，单元格里的数据是 json 格式，希望通过自定义一个函数完成取数。**

取数公式如：

JSONVAL('{"k1":"v1", "k2":["v21", "v22"], "k3":{"k31":"v31"}}', 'k1') -> v1
    JSONVAL('{"k1":"v1", "k2":["v21", "v22"], "k3":{"k31":"v31"}}', 'k2', 0) -> v21
    JSONVAL('{"k1":"v1", "k2":["v21", "v22"], "k3":{"k31":"v31"}}', 'k3', 'k31') -> v31
    JSONVAL('[1, "2", {"k1":"v1"}]', 2, 'k1') -> v1

Web 项目使用了 Gson 解析和生成 json 格式的数据，这里基于 Gson 实现。

代码如下：

package com.fr.function;
    
    import com.fr.script.AbstractFunction;
    import com.fr.stable.Primitive;
    import com.google.gson.JsonArray;
    import com.google.gson.JsonElement;
    import com.google.gson.JsonObject;
    import com.google.gson.JsonParser;
    
    /**
     * 帆软json取数,支持多层级
     * 如：
     * JSONVAL('{"k1":"v1", "k2":["v21", "v22"], "k3":{"k31":"v31"}}', 'k1') -> v1
     * JSONVAL('{"k1":"v1", "k2":["v21", "v22"], "k3":{"k31":"v31"}}', 'k2', 0) -> v21
     * JSONVAL('{"k1":"v1", "k2":["v21", "v22"], "k3":{"k31":"v31"}}', 'k3', 'k31') -> v31
     * JSONVAL('[1, "2", {"k1":"v1"}]', 2, 'k1') -> v1
     * @author ConstXiong
     */
    public class JSONVAL extends AbstractFunction{
    
    	private static final long serialVersionUID = 1L;
    
    	@Override
    	public Object run(Object[] arg) {
    		int paramLength = arg.length;
    		if (paramLength < 2 || arg[0] == null || arg[1] == null) {
    			return Primitive.ERROR_NAME;
    		}
    		try {
    			JsonParser parser = new JsonParser();
    			JsonElement jsonEle = parser.parse(arg[0].toString());
    			for (int i = 1; i < paramLength; i++) {
    				if (jsonEle.isJsonObject() && arg[i] instanceof String) {
    					jsonEle = ((JsonObject)jsonEle).get(arg[i].toString());
    				} else if (jsonEle.isJsonArray() && arg[i] instanceof Integer) {
    					jsonEle = ((JsonArray)jsonEle).get((Integer)arg[i]);
    				} else {
    					return Primitive.ERROR_VALUE;
    				}
    			}
    			//此时 jsonEle 仍可能是 JsonObject 或 JsonArray，暂不处理
    			return jsonEle.getAsString();
    		} catch (Exception e) {
    			return Primitive.ERROR_VALUE;
    		}
    	}
    	
    }

使用如图：

![format_png][]

--------------------

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[format_png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly93d3cuamF2YW5hdi5jb20vYWltZ3MvaW1hZ2VfXzIwMjAwMjI1MjI1NzIzLnBuZw?x-oss-process=image/format,png
[Link 1]: https://www.javanav.com/interview/93b0069472fd479393006c0e73043fc4.html
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[Oracle]: https://www.javanav.com/interview/5f29e9677edf4a16be3dce30d257c9ab.html
[Redis]: https://www.javanav.com/interview/066c62b3af4d4827b2243a822c3084a9.html
[Dubbo]: https://www.javanav.com/interview/9a3e7a7740324757abaab953f7ebc455.html