Brotherc 博客

Guava

Guava

# 常用操作

# Maps.newHashMap()

// 原生和使用Maps.newHashMap()唯一的区别就是简化代码，一个需要你手动加泛型，一个不需要你手动加
// jdk 1.8 之后已经不用加泛型了
Map<String, Object> result = new HashMap<String,Object>();
Map<String, Object> result = Maps.newHashMap();
1
2
3
4

# Joiner 和 Splitter

Map<String, String> join = Splitter.on("&").withKeyValueSeparator("=").split("id=1&name=lcs");
String split = Joiner.on("&").withKeyValueSeparator("=").join(join);
1
2
// skipNulls会过滤掉空的参数，包括数组中的null值。
Joiner.on("|").skipNulls().join(stringList);
// usefornull会以参数替换空的参数，包括数组中的null值。
Joiner.on("|").useForNull("no value").join(stringList);
1
2
3
4
// join参数可以很复杂
String result = Joiner.on("_").join("user_common_count", "name", new Object[]{"nick","adidas",10000})
1
2

# MD5加密

public class HashUtils {

	private static final HashFunction FUNCTION = Hashing.md5();

	private static final String SALT = "abcd";

	public static String encryPassword(String password){
	   HashCode hashCode =	FUNCTION.hashString(password + SALT, Charset.forName("UTF-8"));
	   return hashCode.toString();
	}

}
1
2
3
4
5
6
7
8
9
10
11
12

参考：
https://www.tinymind.net.cn/articles/6e6def50718372 (opens new window)
参考：
https://ifeve.com/google-guava-hashing/ (opens new window)

# Cache

private final Cache<String, String> cache =
    CacheBuilder.newBuilder().maximumSize(100).expireAfterAccess(15, TimeUnit.MINUTES)
        .removalListener(new RemovalListener<String, String>() {

          @Override
          public void onRemoval(RemovalNotification<String, String> notification) {
            ...
          }
        }).build();
1
2
3
4
5
6
7
8
9

# InputStream to String

InputStream inputStream = new FileInputStream("d:/sample.txt");
String text = CharStreams.toString(new InputStreamReader(inputStream, "UTF-8"));
1
2

参考：
https://www.cnblogs.com/mistor/p/6127336.html (opens new window)

简单工厂