将类的JVM规范名称转换为SimpleName

ClassNameUtil.java

import com.google.common.collect.ImmutableMap;

import java.util.Map;

/**
 * @author duqi
 * @createTime 2018/8/14 下午3:18
 **/
public class ClassNameUtil {

    private static final Map<String, String> descriptorsMap = ImmutableMap.<String, String>builder()
            .put("B", "byte")        //signed byte
            .put("C", "char")        //Unicode character code point in the Basic Multilingual Plane, encoded with UTF-16
            .put("D", "double")      //double-precision floating-point value
            .put("F", "float")       //single-precision floating-point value
            .put("I", "int")         //integer
            .put("J", "long")        //long integer
            .put("S", "short")       //signed short
            .put("Z", "boolean")     //true or false
            .build();
    // L ClassName ;，用于表示一个类名
    // [ 开头，表示是一个数组

    public static String convertNameToSimpleName(String sigName) {
        if (sigName == null) {
            return null;
        }

        if (sigName.contains(";")) {
            sigName = sigName.substring(0, sigName.length() - 1);
        }
        StringBuilder builder = new StringBuilder();
        int length = sigName.length();
        int arrLen = sigName.lastIndexOf("[");

        if (sigName.charAt(arrLen + 1) == 'L') {
            builder.append(sigName, arrLen + 2, length);
        } else {
            String simpSig = descriptorsMap.get(sigName.substring(arrLen + 1, length));
            if (simpSig == null) {
                builder.append(sigName);
            } else {
                builder.append(simpSig);
            }
        }

        while (arrLen-- > -1) {
            builder.append("[]");
        }

        return builder.toString();
    }

    public static void main(String[] args) {
        System.out.println(convertNameToSimpleName("[I"));
        System.out.println(convertNameToSimpleName("[[I"));
        System.out.println(convertNameToSimpleName("[Ljava.lang.String;"));
        System.out.println(convertNameToSimpleName("[Ljava.lang.management.MemoryUsage;"));
        System.out.println(convertNameToSimpleName("java.util.TreeMap"));
    }
}