Code片斷： .properties屬性文件操做工具類 & JSON工具類

時間 2019-11-09

標籤 code 片斷 properties 屬性文件工具 json 欄目 JavaScript 简体版

原文原文鏈接

摘要: 原創出處:www.bysocket.com 泥瓦匠BYSocket 但願轉載，保留摘要，謝謝！ 「貴專」 — 泥瓦匠java

1、java.util.Properties API & 案例

java.util.Properties 是一個屬性集合。常見的api有以下：git

load(InputStream inStream) 從輸入流中讀取屬性
getProperty(String key) 根據key，獲取屬性值
getOrDefault(Object key, V defaultValue) 根據key對象，獲取屬性值須要強轉

首先在resources目錄下增長/main/resources/fast.properties：github

fast.framework.name=fast
fast.framework.author=bysocket
fast.framework.age=1

而後直接上代碼PropertyUtil.java：json

/**
 * .properties屬性文件操做工具類
 *
 * Created by bysocket on 16/7/19.
 */
public class PropertyUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(PropertyUtil.class);

    /** .properties屬性文件名後綴 */
    public static final String PROPERTY_FILE_SUFFIX	= ".properties";

    /**
     * 根據屬性文件名,獲取屬性
     *
     * @param propsFileName
     * @return
     */
    public static Properties getProperties(String propsFileName) {
        if (StringUtils.isEmpty(propsFileName))
            throw new IllegalArgumentException();

        Properties  properties  = new Properties();
        InputStream inputStream = null;

        try {

            try {
                /** 加入文件名後綴 */
                if (propsFileName.lastIndexOf(PROPERTY_FILE_SUFFIX) == -1) {
                    propsFileName += PROPERTY_FILE_SUFFIX;
                }

                inputStream = Thread.currentThread().getContextClassLoader()
                        .getResourceAsStream(propsFileName);
                if (null != inputStream)
                    properties.load(inputStream);
            } finally {
                if ( null != inputStream) {
                    inputStream.close();
                }
            }

        } catch (IOException e) {
            LOGGER.error("加載屬性文件出錯!",e);
            throw new RuntimeException(e);
        }

        return properties;
    }

    /**
     * 根據key,獲取屬性值
     *
     * @param properties
     * @param key
     * @return
     */
    public static String getString(Properties properties, String key){
        return properties.getProperty(key);
    }

    /**
     * 根據key,獲取屬性值
     *
     * @param properties
     * @param key
     * @param defaultValue
     * @return
     */
    public static String getStringOrDefault(Properties properties, String key, String defaultValue){
        return properties.getProperty(key,defaultValue);
    }

    /**
     * 根據key,獲取屬性值
     *
     * @param properties
     * @param key
     * @param defaultValue
     * @param <V>
     * @return
     */
    public static <V> V getOrDefault(Properties properties, String key, V defaultValue){
        return (V) properties.getOrDefault(key,defaultValue);
    }
}

UT以下：api

/**
 * {@link PropertyUtil} 測試用例
 * <p/>
 * Created by bysocket on 16/7/19.
 */
public class PropertyUtilTest {

    @Test
    public void testGetProperties() {
        Properties properties = PropertyUtil.getProperties("fast");
        String fastFrameworkName = properties.getProperty("fast.framework.name");
        String authorName        = properties.getProperty("fast.framework.author");
        Object age               = properties.getOrDefault("fast.framework.age",10);
        Object defaultVal        = properties.getOrDefault("fast.framework.null",10);
        System.out.println(fastFrameworkName);
        System.out.println(authorName);
        System.out.println(age.toString());
        System.out.println(defaultVal.toString());
    }

    @Test
    public void testGetString() {
        Properties properties = PropertyUtil.getProperties("fast");
        String fastFrameworkName = PropertyUtil.getString(properties,"fast.framework.name");
        String authorName        = PropertyUtil.getString(properties,"fast.framework.author");
        System.out.println(fastFrameworkName);
        System.out.println(authorName);
    }

    @Test
    public void testGetOrDefault() {
        Properties properties = PropertyUtil.getProperties("fast");
        Object age               = PropertyUtil.getOrDefault(properties,"fast.framework.age",10);
        Object defaultVal        = PropertyUtil.getOrDefault(properties,"fast.framework.null",10);
        System.out.println(age.toString());
        System.out.println(defaultVal.toString());
    }
}

Run Console:app

1
10
fast
bysocket
1
10
fast
bysocket

相關對應代碼分享在 Github 主頁socket

2、JACKSON 案例

首先，加個Maven 依賴:ide

<!-- Jackson -->
		<dependency>
			<groupId>org.codehaus.jackson</groupId>
			<artifactId>jackson-mapper-asl</artifactId>
			<version>1.9.13</version>
		</dependency>
		<dependency>
			<groupId>org.codehaus.jackson</groupId>
			<artifactId>jackson-jaxrs</artifactId>
			<version>1.9.13</version>
		</dependency>

而後直接上代碼JSONUtil：工具

/**
 * JSON 工具類
 * <p/>
 * Created by bysocket on 16/7/19.
 */
public class JSONUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(JSONUtil.class);

    /**
     * 默認JSON類
     **/
    private static final ObjectMapper mapper = new ObjectMapper();

    /**
     * 將 Java 對象轉換爲 JSON 字符串
     *
     * @param object
     * @param <T>
     * @return
     */
    public static <T> String toJSONString(T object) {
        String jsonStr;
        try {
            jsonStr = mapper.writeValueAsString(object);
        } catch (Exception e) {
            LOGGER.error("Java Object Can't covert to JSON String!");
            throw new RuntimeException(e);
        }
        return jsonStr;
    }


    /**
     * 將 JSON 字符串轉化爲 Java 對象
     *
     * @param json
     * @param clazz
     * @param <T>
     * @return
     */
    public static <T> T toObject(String json, Class<T> clazz) {
        T object;
        try {
            object = mapper.readValue(json, clazz);
        } catch (Exception e) {
            LOGGER.error("JSON String Can't covert to Java Object!");
            throw new RuntimeException(e);
        }
        return object;
    }

}

UT以下:測試

/**
 * {@link JSONUtil} 測試用例
 * <p/>
 * Created by bysocket on 16/7/19.
 */
public class JSONUtilTest {

    @Test
    public void testToJSONString() {
        JSONObject jsonObject = new JSONObject(1, "bysocket", 33);
        String jsonStr = JSONUtil.toJSONString(jsonObject);
        Assert.assertEquals("{\"age\":1,\"name\":\"bysocket\",\"id\":33}", jsonStr);
    }

    @Test(expected = RuntimeException.class)
    public void testToJSONStringError() {
        JSONUtil.toJSONString(System.out);
    }

    @Test
    public void testToObject() {
        JSONObject jsonObject = new JSONObject(1, "bysocket", 33);
        String jsonStr = JSONUtil.toJSONString(jsonObject);
        JSONObject resultObject = JSONUtil.toObject(jsonStr, JSONObject.class);
        Assert.assertEquals(jsonObject.toString(), resultObject.toString());
    }

    @Test(expected = RuntimeException.class)
    public void testToObjectError() {
        JSONUtil.toObject("{int:1}", JSONObject.class);
    }
}

class JSONObject {
    int age;
    String name;
    Integer id;

    public JSONObject() {
    }

    public JSONObject(int age, String name, Integer id) {
        this.age = age;
        this.name = name;
        this.id = id;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    @Override
    public String toString() {
        return "JSONObject{" +
                "age=" + age +
                ", name='" + name + '\'' +
                ", id=" + id +
                '}';
    }
}

Run Console（拋出了異常信息）:

16/07/19 23:09:13 ERROR util.JSONUtil: JSON String Can't covert to Java Object!
16/07/19 23:09:13 ERROR util.JSONUtil: Java Object Can't covert to JSON String!