小编ber*_*ard的帖子

我在Spring MVC中有一个带有可选路径变量的方法.我试图在没有提供可选路径变量的情况下测试它.

来自Controller的片段,用于调用的资源URI-

@RequestMapping(value = "/some/uri/{foo}/{bar}", method = RequestMethod.PUT)
public <T> ResponseEntity<T> someMethod(@PathVariable("foo") String foo, @PathVariable(value = "bar", required = false) String bar) {

    LOGGER.info("foo: {}, bar: {}", foo, bar);
}

我使用MockMvc测试的片段 -

//inject context
@Autowired
private WebApplicationContext webApplicationContext;

protected MockMvc mockMvc;

@Before
public void setup() {
    //build mockMvc
    mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
}

@Test
public void someMethodTest() throws Exception {
    //works as expected
    mockMvc.perform(put("/some/uri/{foo}/{bar}", "foo", "bar"))
            .andExpect(status().isOk()); //works

    //following doesn't work

    //pass null for optional
    mockMvc.perform(put("/some/uri/{foo}/{bar}", "foo", null))
            .andExpect(status().isOk()); //throws …

我在使用类型参数初始化类时遇到问题.这似乎是Java类型推断的一个缺点,我想知道是否有办法绕过这个或更好的方法实现这一点.

public class ParentModel {}

public class ChildModel extends ParentModel {}

public class Service<E extends ParentModel, T extends Collection<E>> {
    private Class<T> classOfT;
    private Class<E> classOfE;

    public Service(Class<E> classOfE, Class<T> classOfT) {
        this.classOfE = classOfE;
        this.classOfT = classOfT;
    }
}

public class BusinessLogic {
    public void someLogic() {
        Service<ChildModel, ArrayList<ChildModel>> service = new 
            Service<ChildModel, ArrayList<ChildModel>>(ChildModel.class, ArrayList.class);
    }
}

编译时错误在BusinessLogic::someLogic():

构造函数Service <ChildModel,ArrayList <ChildModel >>(Class <ChildModel>,Class <ArrayList>)未定义

编译为Java 7.

我为Java 7和C#(.net 3.5)编写了一段相同的(相似的)代码,并得到了令人困惑的输出.请帮助我理解这种行为:

Java的:

public class strTest {
    public static void main(String [] s) {      
        String s1 = "abc";
        String s2 = new String(new char[] {'a', 'b', 'c'});
        System.out.println(s1 == s2);                      // false
        System.out.println(((Object)s1) == ((Object)s2));  // false
        System.out.println(s1.equals(s2));                 // true
    }
}

输出:false false true

C#:

namespace ConsoleApplication1
{
    class Program2
    {
        static void Main(string[] args)
        {
            String s1 = "abc";
            String s2 = new String(new Char[] {'a', 'b', 'c'});
            Console.WriteLine(s1 == s2);                     // true
            Console.WriteLine(((Object)s1) == ((Object)s2)); // …