Java-读取properties配置文件反射对类属性赋值

背景：

　　Java一般的类属性赋值方式是：通过读取或者外部传入的参数，然后调用属性的set方法进行赋值

　　这种方法，每次修改模板类，就需要修改所有对类操作赋值的方法

解决思路：

　　是否可以通过设定默认规则由一个通用方法连接类和输入参数，做到类增加属性后，根据入参是否包含改属性自动赋值

　　如下是一种简单实现，具体如下：

　1、Utils方法和测试的main函数

package com.hs.bigdata.ignite.testcase.utils;

import com.hs.bigdata.ignite.testcase.env.EnvConfig;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.*;

public class ConfigUtils {

    public static void main(String[] args) throws IOException, InvocationTargetException, IllegalAccessException {

        String filePath = "/config.properties";
        Properties properties = getProperties(filePath);
        for (Object key : properties.keySet()) {
            System.out.println(key + "=" + properties.get(key));
        }
        Map<String, String> configMap = propertiesToMap(properties);
        EnvConfig envConfig = (EnvConfig) mapToObject(new EnvConfig(), configMap);
        System.out.println(envConfig.toString());
    }

    /**
     * configMap 属性赋值给对象，对象入参全部是String
     * @param object
     * @return
     */
    public static Object mapToObject(Object object,Map<String,String> configMap) throws InvocationTargetException, IllegalAccessException {
        Method[] methods = object.getClass().getMethods();
        for (Method method : methods) {
            String name = method.getName();
            if(name.startsWith("set")) {
                String temp = name.substring(3);
                String key = temp.substring(0,1).toLowerCase() + temp.substring(1);
                String value = configMap.get(key);
                method.invoke(object, value);
            }
        }
        return object;
    }

    /**
     * properties 转成 Map
     * @param properties
     * @return
     */
    public static Map<String,String> propertiesToMap(Properties properties){
        int size = properties.size();
        Map<String,String> map = new HashMap<>(size);
        Set<Map.Entry<Object, Object>> entries = properties.entrySet();
        for (Object object : properties.keySet()) {
            String key = (String) object;
            String value = properties.getProperty(key, "");
            map.put(key,value);
        }
        return map;
    }
    /**
     * 从指定目录下加载 properties文件到properties中
     * @param path
     * @return
     */
    public static Properties getProperties(String path) throws IOException {
        InputStream inputStream = null;
        InputStreamReader inputStreamReader = null;
        Properties properties = null;
        try {
            inputStream = ConfigUtils.class.getResourceAsStream(path);
            inputStreamReader = new InputStreamReader(inputStream, "UTF-8");
            properties = new Properties();
            properties.load(inputStreamReader);
        }finally {
            if(null != inputStreamReader){
                inputStreamReader.close();
            }
            if(null != inputStream){
                inputStream.close();
            }
        }
        return properties;
    }
}

2、EnvConfig类

package com.hs.bigdata.ignite.testcase.env;

public class EnvConfig {

    private String jdbcUrl;


    public String getJdbcUrl() {
        return jdbcUrl;
    }

    public void setJdbcUrl(String jdbcUrl) {
        this.jdbcUrl = jdbcUrl;
    }

    @Override
    public String toString() {
        return "EnvConfig{" +
                "jdbcUrl='" + jdbcUrl + '\'' +
                '}';
    }
}