spring 获取方法参数签名

最新推荐文章于 2024-05-23 18:37:51 发布

原创最新推荐文章于 2024-05-23 18:37:51 发布 · 2.1k 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#源码 #spring #methods

spring 专栏收录该内容

14 篇文章

订阅专栏

本文介绍如何使用Spring框架的DefaultParameterNameDiscoverer类来获取方法参数名称。通过具体示例展示了如何利用Spring的类来实现参数签名的获取。

最近在用CXF restful ,cxf3 集成了Validation, 但hibernate validation返回的异常信息里不能准确的显示出方法参数签名，只能以arg0 arg1来表示参数，对于我们的外部api来说我只能说hibernate做的真烂，spring 在处理这方面就做的很好，最后还是借用下spring的类来实现，下面给出spring的如何获取参数方法签名。

 @Test
    public void testParameterName() {
        DefaultParameterNameDiscoverer discoverer = new DefaultParameterNameDiscoverer();
        AccountService service = new AccountService();
        Method[] methods = service.getClass().getDeclaredMethods();
        for (Method method : methods) {
            String[] result = discoverer.getParameterNames(method);
            if (result != null) {
                for (String name : result) {
                    System.out.println(name);
                }
            }
        }
    }

public class AccountService {


    public String getAccountName(String id, int sex){
        
        return "test";
    }
}

org.springframework.core.PrioritizedParameterNameDiscoverer类的实现

@Override
	public String[] getParameterNames(Method method) {
		for (ParameterNameDiscoverer pnd : this.parameterNameDiscoverers) {
			String[] result = pnd.getParameterNames(method);//看下面实现
			if (result != null) {
				return result;
			}
		}
		return null;
	}

org.springframework.core.LocalVariableTableParameterNameDiscoverer.getParameterNames(Method)

@Override
	public String[] getParameterNames(Method method) {
		Method originalMethod = BridgeMethodResolver.findBridgedMethod(method);
		Class<?> declaringClass = originalMethod.getDeclaringClass();
		Map<Member, String[]> map = this.parameterNamesCache.get(declaringClass);//参数缓存
		if (map == null) {
			map = inspectClass(declaringClass);//
			this.parameterNamesCache.put(declaringClass, map);
		}
		if (map != NO_DEBUG_INFO_MAP) {
			return map.get(originalMethod);
		}
		return null;
	}
        /**
 <span style="white-space:pre">	</span>* Inspects the target class. Exceptions will be logged and a maker map returned
<span style="white-space:pre">	</span> * to indicate the lack of debug information.
 <span style="white-space:pre">	</span>*/
<span style="white-space:pre">	</span>private Map<Member, String[]> inspectClass(Class<?> clazz) {
<span style="white-space:pre">		</span>InputStream is = clazz.getResourceAsStream(ClassUtils.getClassFileName(clazz));
<span style="white-space:pre">		</span>if (is == null) {//看类是否可以加载
<span style="white-space:pre">			</span>// We couldn't load the class file, which is not fatal as it
<span style="white-space:pre">			</span>// simply means this method of discovering parameter names won't work.
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Cannot find '.class' file for class [" + clazz +
<span style="white-space:pre">				</span>"] - unable to determine constructor/method parameter names");
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>return NO_DEBUG_INFO_MAP;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>try {
<span style="white-space:pre">		</span>ClassReader classReader = new ClassReader(is);//spring核心包ASM类解析工具
<span style="white-space:pre">		</span>Map<Member, String[]> map = new ConcurrentHashMap<Member, String[]>(32);
<span style="white-space:pre">		</span>classReader.accept(new ParameterNameDiscoveringVisitor(clazz, map), 0);
<span style="white-space:pre">		</span>return map;
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (IOException ex) {
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("Exception thrown while reading '.class' file for class [" + clazz +
<span style="white-space:pre">				</span>"] - unable to determine constructor/method parameter names", ex);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>catch (IllegalArgumentException ex) {
<span style="white-space:pre">			</span>if (logger.isDebugEnabled()) {
<span style="white-space:pre">				</span>logger.debug("ASM ClassReader failed to parse class file [" + clazz +
<span style="white-space:pre">				</span>"], probably due to a new Java class file version that isn't supported yet " +
<span style="white-space:pre">				</span>"- unable to determine constructor/method parameter names", ex);
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>finally {
<span style="white-space:pre">			</span>try {
<span style="white-space:pre">				</span>is.close();
<span style="white-space:pre">			</span>}
<span style="white-space:pre">			</span>catch (IOException ex) {
<span style="white-space:pre">			</span>// ignore
<span style="white-space:pre">			</span>}
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return NO_DEBUG_INFO_MAP;
<span style="white-space:pre">	</span>}