一、java.util.Properties API & 案例
java.util.Properties 是一個屬性集合。常見的api有如下：
- 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，獲取屬性值需要強轉
首先在resources目錄下增加/main/resources/fast.properties：
fast.framework.name=fast
fast.framework.author=bysocket
fast.framework.age=1然後直接上代碼PropertyUtil.java：
/**
* .properties屬性文件操作工具類
*
* 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如下：
/**
* {@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:
1
10
fast
bysocket
1
10
fast
bysocket相關對應代碼分享在 Github 主頁
二、JACKSON 案例
首先，加個Maven 依賴:
<!-- 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>然後直接上代碼JSONUtil：
/**
* 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 對象轉換為 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 字符串轉化為 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如下:
/**
* {@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!三、小結
相關對應代碼分
本文章為轉載內容，我們尊重原作者對文章享有的著作權。如有內容錯誤或侵權問題，歡迎原作者聯繫我們進行內容更正或刪除文章。
