java如何检查变量名是否包含字符串，然后输出字符串变量内容

Question

我有这4个变量

private final String PROG_DEPT = "PROGRAMMING/ENGINEERING";
private final String DES_DEPT = "DESIGN/WRITING";
private final String ART_DEPT = "VISUAL ARTS";
private final String SOUND_DEPT = "AUDIO";

我想做的是得到一个字符串，并将其与变量进行比较，然后输出变量包含的内容（如果它等于它）

例如，如果我的字符串等于“ART_DEPT”，则检查是否存在名为ART_DEPT的变量，然后输出“VISUAL ARTS”

我想把它放在一个2D字符串数组或列表中，但我不确定该怎么做

Answer 1

听起来像是在寻找反射（或者如果希望使用不同的数据类型，而不是在类中查找变量，则使用Map<String, String>）。看起来映射方法已经被很好地涵盖了，所以这只是因为我感兴趣，这里是反射方法（不是说这不是解决这个问题的最佳方法，而是因为您要求检查变量是否存在，然后获取它的值）

import java.lang.reflect.Field;

public class SOQuestion {
  private final String PROG_DEPT = "PROGRAMMING/ENGINEERING";
  private final String DES_DEPT = "DESIGN/WRITING";
  private final String ART_DEPT = "VISUAL ARTS";
  private final String SOUND_DEPT = "AUDIO";

  public static void main(String ... args) throws IllegalArgumentException, IllegalAccessException, InstantiationException {
    System.out.println(reflectValue("ART_DEPT", SOQuestion.class));
    System.out.println(reflectValue("COMP_DEPT", SOQuestion.class));
  }

  public static String reflectValue(String varible, Class thing) throws IllegalArgumentException, IllegalAccessException, InstantiationException {
    Field[] fs = thing.getDeclaredFields();
    for(int i = 0; i < fs.length; i++) {
      if(fs[i].getName().equals(varible)) {
        fs[i].setAccessible(true);
        return (String) fs[i].get(thing.newInstance());
      }
    }
    return null;
  }
}

第一个打印"ATR_DEPT"的请求将打印VISUAL ARTS，第二个对不存在的"COMP_DEPT"的请求将返回null

Answer 2

试试这个

      List<String> list=new ArrayList<>();
      list.add("private final String PROG_DEPT = \"PROGRAMMING/ENGINEERING\";");
      list.add("private final String DES_DEPT = \"DESIGN/WRITING\";");
      list.add("private final String ART_DEPT = \"VISUAL ARTS\";");
      list.add("private final String SOUND_DEPT = \"AUDIO\";");
      String search="ART_DEPT";
      for (String i:list){
         if(i.contains(search)){
             System.out.println(i.split("=")[1].replaceAll(";",""));
         }
      }

住在这里。您可以使用Map来实现这一点，但要实现这一点，您必须从这些字符串创建一个Map

Answer 3

我会使用枚举：

package com.stackoverflow.so18327373;

public class App {
    public static void main(final String[] args) {
        final String in = "DES_DEPT";
        try {
            final Departement departement = Departement.valueOf(in);
            System.out.println(departement.getLabel());
        } catch (final IllegalArgumentException ex) {
            // in was not a known departement
            System.err.println("Bad value: " + in);
        }
    }

    public static enum Departement {
        PROG_DEPT("PROGRAMMING/ENGINEERING"), 
        DES_DEPT("DESIGN/WRITING"), 
        ART_DEPT("VISUAL ARTS"), 
        SOUND_DEPT("AUDIO");

        private final String label;

        private Departement(final String label) {
            this.label = label;
        }

        public String getLabel() {
            return this.label;
        }
    }
}

然后使用valueOf()

Answer 4

您要查找的数据类型是Map<String, String>

Map<String, String> departmentNames = new HashMap<String, String>();
departmentNames.put("PROG_DEPT", "PROGRAMMING/ENGINEERING");
departmentNames.put("DES_DEPT", "DESIGN/WRITING");
//...etc...

//...

String dept = "PROG_DEPT";
String deptName = departmentNames.get(dept);
System.out.println(deptName); //outputs "PROGRAMMING/ENGINEERING"

Map将唯一键绑定到值。在这种情况下，两者都具有类型String。您可以使用put(key, value)添加绑定，并使用get(key)获取键的绑定

Answer 5

你需要的是一张地图

private final Map<String,String> myMap= new HashMap<String,String>() ;
{
    myMap.put("PROG_DEPT","PROGRAMMING/ENGINEERING");
    myMap.put("DES_DEPT","DESIGN/WRITING");
    myMap.put("ART_DEPT","VISUAL ARTS");
    myMap.put("SOUND_DEPT","AUDIO");
}

然后按以下方式使用：

String input= "ART_DEPT" ;
System.out.println( myMap.get(input) );

Answer 6

您可能希望使用某种Map，例如HashMap<String,String>。我建议您阅读Map接口和HashMap类的Javadocs