test_123=admin

注:value 可用单引号，双引号，不用引号修饰

package com.......test;

import java.io.IOException;

import java.io.InputStream;

import java.util.Properties;

public class PropertiesUtil {

    private static final String PROP_FILE = "test.properties";

    private static Properties properties;

    static {
        properties = new Properties();
        try {
            InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(PROP_FILE);
            BufferedReader bf = new BufferedReader(new InputStreamReader(is, "UTF-8"));//解决读取properties文件中产生中文乱码的问题
            assert (is != null);
            properties.load(bf);

        } catch (IOException e) {
            throw new RuntimeException("读取" + PROP_FILE + "配置文件异常", e);
        }
    }

    public static String getValue(String key) {
        return properties.getProperty(key);
    }
}

    @Test

    public void test() {

        String  keyWord = "test_123";

        String value = PropertiesUtil.getValue(keyWord);

        System.out.println("value = " + value);

    }