1、*先放源码：实体类:public class Person {private Stri艘绒庳焰ng name;private int 锾攒揉敫age;public String getName(){ return name;}public void setName(String name) {this.name = name;}public int getAge() {return age;}public void setAge(int age){ if (age < 0 ) { throw new IllegalArgumentException("age is invalid"); } this.age = age;}}测试:public class abc {@Testpublic void aaa(){Person person = new Person();person.setAge(-1);}}
2、*1.try…catch…finally方式public class abc {@Testpublic void aaa(){Person person = new Person();try {person.setAge(-1);} catch (Exception e) {}}}
3、*2.hrows抛异常public class abc {@Testpublic void aaa() throws Exception{FileInputStream fis = new FileInputStream("xxx.txt");fis.close();}}
4、*3.junit annotation方式JUnit中提供了一个expected的annotation来检查异常。@Test(expected = IllegalArgumentException.class) public void shouldGetExceptionWhenAgeLessThan0() { Person person = new Person(); person.setAge(-1); }这种方式看起来要简洁多了，但是无法检查异常中的消息。
5、*4.ExpectedException方式 JUnit7以后提供了一个叫做ExpectedException的Rule来实现对异常的测试。@Rule public ExpectedException exception = ExpectedException.none();@Test public void shouldGetExceptionWhenAgeLessThan0() { Person person = new Person(); exception.expect(IllegalArgumentException.class); exception.expectMessage(containsString("age is invalid")); person.setAge(-1); }这种方式既可以检查异常类型，也可以验证异常中的消息。
6、*5.catch-exception库 有个catch-exception库也可以实现对异常的测廖嘤傥笏试。 首先引用该库。pom.xml<dependency> <groupId>com.googlecode.catch-exception</groupId> <artifactId>catch-exception</artifactId> <version>1.2.0</version> <scope>test</scope> <!-- test scope to use it only in tests --> </dependency>然后这样书写测试。@Test public void shouldGetExceptionWhenAgeLessThan0() { Person person = new Person(); catchException(person).setAge(-1); assertThat(caughtException(),instanceOf(IllegalArgumentException.class)); assertThat(caughtException().getMessage(), containsString("age is invalid")); }这样的好处是可以精准的验证异常是被测方法抛出来的，而不是其它方法抛出来的。catch-exception库还提供了多种API来进行测试。先加载fest-assertion库。<dependency> <groupId>org.easytesting</groupId> <artifactId>fest-assert-core</artifactId> <version>2.0M10</version> </dependency>然后可以书写BDD风格的测试。@Test public void shouldGetExceptionWhenAgeLessThan0() { // given Person person = new Person(); // when when(person).setAge(-1); // then then(caughtException()) .isInstanceOf(IllegalArgumentException.class) .hasMessage("age is invalid") .hasNoCause(); }如果喜欢Hamcrest风格的验证风格的话，catch-exception也提供了相应的Matcher API。@Test public void shouldGetExceptionWhenAgeLessThan0() { // given Person person = new Person(); // when when(person).setAge(-1); // then assertThat(caughtException(), allOf( instanceOf(IllegalArgumentException.class) ,hasMessage("age is invalid") ,hasNoCause())); }