Java - 使用模板从字符串中提取键值对

Question

所以在 org.apache.commons.lang3.text 中有一个名为 StrSubstitutor 的类，它可以接受这样的映射:

Map<String, String> params = new HashMap<String, String>();
params.put("name","Vivek");
params.put("id","900");
params.put("somethingelse","blah");

和这样的模板字符串:

    <data>
       <id>${id}</id>
       <name>${name}</name>
       <something>${somethingelse}</something>
    </data>

生成这样的输出字符串:

   <data>
       <id>900</id>
       <name>Vivek</name>
       <something>blah</something>
   </data>

我想要的恰恰相反。有没有一种方法可以将输出字符串和模板以模板变量作为键并以字符串中的相应值作为值来填充 map ？

PS - 我将使用的字符串不一定总是 XML。这只是一个例子。

编辑:我认为有些人感到困惑，因为变量名称和标签名称相同。标签只是说明性的，与问题无关。我关心的是 ${} 中的变量。我添加了另一个标签来说明我的意思。

Answer 1

这是另一种选择:

import java.util.HashMap;
import java.util.Map;

public class Test{

    public static void main(String[] args){

        //simulate template. Assuming no more than on param in line
        String[] template = new String[]{
                                    "<data>",
                                    "<id>${id}</id>",
                                    "<name>${name}</name>",
                                    "<something>${somethingelse}</something>",
                                    "</data>"
                                    };

        String[] output = new String[]{
                                    "<data>",
                                    "<id>900</id>",
                                    "<name>Vivek</name>",
                                    "<somethingelse>blah</somethingelse>",
                                    "</data>"
                                    };

        Map<String, String> params = getParams(template);

        getValues(params, output);

        for(String key : params.keySet()) {
            System.out.println(key +" : " + params.get(key));
        }
    }

    private static Map<String, String> getParams(String[] template) {

        Map<String, String> params = new HashMap<String, String>();

        for (String line : template) {

            //get location of 3 chars ${}
            int index$ = line.indexOf("$");
            int indexLeftB = line.indexOf("{");
            int indexRightB = line.indexOf("}");

            //make sure all ${} are present
            if((index$ <0) || (indexLeftB <0) || (indexRightB <0) ) {
                continue;
            }

            //make sure they are in the right order
            if( ((indexLeftB - index$) !=1) || (indexRightB < indexLeftB)) {
                continue;
            }

            //get param
            String param = getParamFromLine(line, indexLeftB+1 , indexRightB);

            if(param != null) {

                params.put(param,null);
            }
        }

        return params;
    }

    private static void getValues(Map<String, String> params, String[] output) {

        //iterate over map
        for(String param : params.keySet()) {

            String tag = "<"+param+">"; //like <name>
            String closeTag = "</"+param+">"; //like <name>

            //iterate over output
            for(String line : output) {

                line = line.trim(); //remove all whitespace
                //look for first occurrence of patternToSearch
                int index1 = line.indexOf(tag, 0);
                int index2 = line.indexOf(closeTag, index1);

                //make sure there are 2 occurrences in
                if((index1 < 0) || (index2 < 0)) {
                    continue;
                }

                String value = getParamFromLine(line, index1+ tag.length(), index2);
                if(value != null) {

                    params.put(param, value);
                }
            }
        }
    }

    private static String getParamFromLine(String line, int indexLeftB, int indexRightB) {

        String param = line.substring(indexLeftB, indexRightB);

        return (param.trim().length() == 0) ? null : param.trim();
    }
}