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摘要: J2SE5.0新特性之静态导入
J2SE5.0新特性之静态导入<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
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J2se5.0之前,如果需要使用其他类的静态方法,如java.lang.Math中的方法,需要写以下的代码:
double value = Math.log(100)*Math.PI;
现在你只需在静态导入,然后就可以直接在代码中使用静态方法和静态字段:
import static java.lang.Math.*;
…
double value = log(100)*PI;
看一个详细的例子。我们先建一个包含一个静态方法和一个静态字段的类:
<table class=MsoTableGrid style="BACKGROUND: #cccccc; BORDER-COLLAPSE: collapse; mso-yfti-tbllook: 480; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt" cellSpacing=0 cellPadding=0 border=0><tr style="mso-yfti-irow: 0; mso-yfti-firstrow: yes; mso-yfti-lastrow: yes"><td style="BORDER-RIGHT: #d4d0c8; PADDING-RIGHT: 5.4pt; BORDER-TOP: #d4d0c8; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: #d4d0c8; WIDTH: 426.1pt; PADDING-TOP: 0cm; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent" vAlign=top width=568>package com.kuaff.jdk5;
public class StaticClass
{
public static String LABEL = "中国古代名剑";
public static void printList()
{
String[] swords = new String[] { "轩辕夏禹剑", "湛泸", "赤霄", "太阿", "龙渊", "干将", "莫邪", "鱼肠", "纯钧", "承影" };
for (String name : swords)
{
System.out.printf("%s%n", name);
}
}
}
</td></tr></table>新建一个类,静态导入上面的字段和方法,并使用它们:
<table class=MsoTableGrid style="BACKGROUND: #cccccc; BORDER-COLLAPSE: collapse; mso-yfti-tbllook: 480; mso-padding-alt: 0cm 5.4pt 0cm 5.4pt" cellSpacing=0 cellPadding=0 border=0><tr style="mso-yfti-irow: 0; mso-yfti-firstrow: yes; mso-yfti-lastrow: yes"><td style="BORDER-RIGHT: #d4d0c8; PADDING-RIGHT: 5.4pt; BORDER-TOP: #d4d0c8; PADDING-LEFT: 5.4pt; PADDING-BOTTOM: 0cm; BORDER-LEFT: #d4d0c8; WIDTH: 426.1pt; PADDING-TOP: 0cm; BORDER-BOTTOM: #d4d0c8; BACKGROUND-COLOR: transparent" vAlign=top width=568>package com.kuaff.jdk5;
import static com.kuaff.jdk5.StaticClass.*;//静态导入
public class StaticImportShow
{
public void testSI()
{
System.out.printf("%s:%n",LABEL);
printList();
}
public static void main(String[] args)
{
StaticImportShow show = new StaticImportShow();
show.testSI();
}
}
</td></tr></table>
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