[java学习点滴]PropertiesUtil 读取properties配置帮助类

1 package com.hager.util;
2
3 import java.io.File;
4 import java.io.FileInputStream;
5 import java.io.IOException;
6 import java.io.InputStream;
7 import java.util.Map;
8 import java.util.Properties;
9
10 /**
11  * @Author wzh
12  * @Date 2017/1/16.
13  * @Version V1.0 15  * @Description 读取properties配置帮助类
16  */
17 public class PropertiesUtil {
18
19
20     private PropertiesUtil() {
21     }
22
23     /**
24      * 读取properties文件
25      *
26      * @param file 文件路径
27      * @return 返回properties 对象
28      */
29     public static Properties fromFile(String file) {
30         InputStream stream = null;
31
32         try {
33             stream = new FileInputStream(new File(file));
34             return fromStream(stream);
35         } catch (IOException e) {
36             throw new RuntimeException(e);
37         } finally {
38             close(stream);
39         }
40     }
41
42     /**
43      * 读取properties文件
44      *
45      * @param file 文件路径
46      * @return 返回properties 对象
47      */
48     public static Properties fromClasspath(String file) {
49         InputStream stream = null;
50         try {
51             stream = Thread.currentThread().getContextClassLoader().getResourceAsStream(file);
52             return fromStream(stream);
53         } catch (Exception e) {
54             throw new RuntimeException(e);
55         } finally {
56             close(stream);
57         }
58     }
59
60     /**
61      * convert stream  to properties
62      *
63      * @param stream InputStream
64      * @return Properties
65      * @throws IOException
66      */
67     private static Properties fromStream(InputStream stream) throws IOException {
68         Properties dest = new Properties();
69         Properties src = new Properties();
70         src.load(stream);
71
72         // 如果key value为字符串，需要trim一下
73         for (Map.Entry<Object, Object> entry : src.entrySet()) {
74             Object key = entry.getKey();
75             Object value = entry.getValue();
76
77             Object newKey = key;
78             Object newValue = value;
79             if (newKey instanceof String) {
80                 newKey = key.toString().trim();
81             }
82
83             if (newValue instanceof String) {
84                 newValue = value.toString().trim();
85             }
86
87             dest.put(newKey, newValue);
88         }
89
90         return dest;
91     }
92
93     /**
94      * dispose stream
95      *
96      * @param stream InputStream
97      */
98     private static void close(InputStream stream) {
99         if (stream != null) {
100             try {
101                 stream.close();
102             } catch (IOException e) {
103             }
104         }
105     }
106 }

src/main/resources/test.properties;
内容简单：

test=aaa

1  @Test
2     public void fromClasspath() throws Exception {
3         String fileName = "test.properties";
4
5         Properties properties = PropertiesUtil.fromClasspath(fileName);
6         String values = properties.getProperty("test");
7         System.out.println(JsonHelper.serialize(properties));
8
9         Assert.assertEquals("aaa", values);
10         Assert.assertNotNull(properties);
11     }

{"test":"aaa"}

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