92 lines
3.2 KiB
Java
92 lines
3.2 KiB
Java
/*
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* The MIT License (MIT)
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*
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* Copyright © 2020 xrv <xrg@live.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package io.github.ehlxr.test;
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import java.io.IOException;
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import java.util.Arrays;
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import java.util.LinkedHashMap;
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import java.util.List;
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import java.util.StringJoiner;
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import java.util.stream.Collectors;
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/**
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* Created by ehlxr on 2016/12/15.
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*/
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public class Test {
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public static void main(String[] args) throws IOException {
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// String s0 = "kvill";
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// String s1 = "kvill";
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// String s2 = "kvill";
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// System.out.println(s0 == s1);
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// System.out.println("**********");
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// s1.intern();
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// s2 = s2.intern(); //把常量池中"kvill"的引用赋给s2
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// System.out.println(s0 == s1);
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// System.out.println(s0 == s1.intern());
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// System.out.println(s0 == s2);
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// LinkedHashMap
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System.out.println("*****LinkedHashMap*****");
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LinkedHashMap<Object, Object> map = new LinkedHashMap<>();
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map.put("a", "111");
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map.put("b", "222");
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map.put("c", "333");
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map.put("d", "444");
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map.put("a", "555");
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System.out.println(map);
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// The String "[George:Sally:Fred]" may be constructed as follows:
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StringJoiner sj = new StringJoiner(":", "[", "]");
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sj.add("George").add("Sally").add("Fred");
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System.out.println(sj);
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// A StringJoiner may be employed to create formatted output from a java.util.stream.Stream using java.util.stream.Collectors.joining(CharSequence). For example:
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List<Integer> numbers = Arrays.asList(1, 2, 3, 4);
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String commaSeparatedNumbers = numbers.stream()
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.map(Object::toString)
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.collect(Collectors.joining(", "));
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System.out.println(commaSeparatedNumbers);
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System.out.println("------------" + (-1 >>> Integer.numberOfLeadingZeros(3)));
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String s = new String("1");
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String t = new String("1");
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String s1 = s.intern();
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String s2 = "1";
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System.out.println(s == s1);
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System.out.println(s1 == s2);
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System.out.println(s == t); // false
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System.out.println(s.intern() == t.intern()); // true
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System.in.read();
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}
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}
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