例子很简单，设计一个程序，输入三个整数，判断这三个整数作为三边的长度能否构成一个三角形，如果可以则返回三角形的类型（普通三角形，等腰三角形或者等边三角形）
　　实现代码（我自己随便写的做个例子用，估计代码质量很差。。）：
public class JudgeTriangle
{
//普通三角形
private static int NORMAL_TRIANGLE = 0;
//等腰三角形
private static int ISOSCELES_TRIANGLE  = 1;
//等边三角形
private static int EQUILATERAL_TRIANGEL = 2;
//无法构成三角形
private static int ERROR_CODE = -1;
public int getNormalTriangle()
{
return NORMAL_TRIANGLE;
}
public int getIsoscelesTriangle()
{
return ISOSCELES_TRIANGLE;
}
public int getEquilateralTriangle()
{
return EQUILATERAL_TRIANGEL;
}
public int getErrorCode()
{
return ERROR_CODE;
}
public int judgeType(int a，int b，int c)
{
if ((a<=0)||(b<=0)||(c<=0))
{
return ERROR_CODE;
}
if ((a+b<c || Math.abs(a-b)>c) || (b+c<a || Math.abs(b-c)>a) || (a+c<b || Math.abs(a-c)>b))
{
return ERROR_CODE;
}
if (a==b || b==c || c==a)
{
if (a==b && b==c)
{
return EQUILATERAL_TRIANGEL;
}
else
{
return ISOSCELES_TRIANGLE;
}
}
else
{
return NORMAL_TRIANGLE;
}
}
}
　　单元测试代码:
import static org.junit.Assert.*;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
public class JudgeTriangleTest {
private static JudgeTriangle judgeTriangle = new JudgeTriangle();
@Before
public void setUp() throws Exception {
}
@Test
public void testIsNormalTriangle() throws Exception {
assertEquals(judgeTriangle.getNormalTriangle()，judgeTriangle.judgeType(3， 4， 5));
}
@Test
public void testIsIsoscelesTriangle() throws Exception {
assertEquals(judgeTriangle.getIsoscelesTriangle()，judgeTriangle.judgeType(2， 2， 3));
}
@Test
public void testEquilateralTriangle() throws Exception {
assertEquals(judgeTriangle.getEquilateralTriangle()，judgeTriangle.judgeType(2， 2， 2));
}
@Test
public void testNotTriangle() throws Exception {
assertEquals(judgeTriangle.getErrorCode()，judgeTriangle.judgeType(10， -10， 10));
assertEquals(judgeTriangle.getErrorCode()，judgeTriangle.judgeType(10， 2， 2));
}
@After
public void tearDown() throws Exception {
}
}