Springboot请求和响应相关注解及使用场景分析

@restcontroller
@requestmapping("/api")
public class mycontroller {
    @requestmapping(value = "/hello", method = requestmethod.get)
    public string sayhello() {
        return "hello, world!";
    }
}

@restcontroller
@requestmapping("/api")
public class mycontroller {
    @getmapping("/hello")
    public string sayhello() {
        return "hello, world!";
    }
    @postmapping("/create")
    public string createitem(@requestbody item item) {
        return "item created";
    }
}

@getmapping("/greet")
public string greet(@requestparam(name = "name", defaultvalue = "world") string name) {
    return "hello, " + name;
}

@getmapping("/items/{id}")
public item getitem(@pathvariable("id") long id) {
    // logic to fetch item by id
    return item;
}

@postmapping("/items")
public item createitem(@requestbody item item) {
    // logic to create item
    return item;
}

@getmapping("/user-agent")
public string getuseragent(@requestheader("user-agent") string useragent) {
    return "user-agent: " + useragent;
}

@getmapping("/items/{id}")
@responsebody
public item getitem(@pathvariable("id") long id) {
    // logic to fetch item by id
    return item;
}

@restcontroller
@requestmapping("/api")
public class mycontroller {
    @getmapping("/items/{id}")
    public item getitem(@pathvariable("id") long id) {
        return item;
    }
}

@postmapping("/items")
@responsestatus(httpstatus.created)
public item createitem(@requestbody item item) {
    return item;
}

@restcontroller
@requestmapping("/api")
public class mycontroller {
    @getmapping("/items/{id}")
    public item getitem(@pathvariable("id") long id) {
        if (id == null) {
            throw new itemnotfoundexception("item not found");
        }
        return item;
    }
    @exceptionhandler(itemnotfoundexception.class)
    @responsestatus(httpstatus.not_found)
    public string handleitemnotfoundexception(itemnotfoundexception ex) {
        return ex.getmessage();
    }
}

@restcontroller
@requestmapping("/api")
@crossorigin(origins = "http://example.com")
public class mycontroller {
    @getmapping("/items/{id}")
    public item getitem(@pathvariable("id") long id) {
        return item;
    }
}

@getmapping("/attributes")
public string getattribute(@requestattribute("myattribute") string myattribute) {
    return "attribute: " + myattribute;
}

@postmapping("/items")
public item createitem(@valid @requestbody item item) {
    return item;
}