How to get reflection method in Java?

1. Get the method to be reflected

When getting the reflection method, there are two methods, getMethod and getDeclaredMethod.

class Class {
 @CallerSensitive
 public Method getMethod(String name, Class<?>... parameterTypes)
 throws NoSuchMethodException, SecurityException {
 Objects.requireNonNull(name);
 SecurityManager sm = System.getSecurityManager();
 if (sm != null) {
 // 1. 检查方法权限
 checkMemberAccess(sm, Member.PUBLIC, Reflection.getCallerClass(), true);
 }
 // 2. 获取方法
 Method method = getMethod0(name, parameterTypes);
 if (method == null) {
 throw new NoSuchMethodException(methodToString(name, parameterTypes));
 }
 // 3. 返回方法的拷贝
 return getReflectionFactory().copyMethod(method);
 }
 @CallerSensitive
 public Method getDeclaredMethod(String name, Class<?>... parameterTypes)
 throws NoSuchMethodException, SecurityException {
 Objects.requireNonNull(name);
 SecurityManager sm = System.getSecurityManager();
 if (sm != null) {
 // 1. 检查方法是权限
 checkMemberAccess(sm, Member.DECLARED, Reflection.getCallerClass(), true);
 }
 // 2. 获取方法
 Method method = searchMethods(privateGetDeclaredMethods(false), name, parameterTypes);
 if (method == null) {
 throw new NoSuchMethodException(methodToString(name, parameterTypes));
 }
 // 3. 返回方法的拷贝
 return getReflectionFactory().copyMethod(method);
 }
}

2. In Java5, a for-each loop is provided, which simplifies looping of arrays and collections. Fore-each loops allow you to iterate over an array without retaining the index in a traditional for loop or calling the hasNext method and next method in a while loop when using an iterator to iterate through the collection.

double[] values = ...;
for(double value : values) {
    // TODO: 处理value
}
 
List<Double> valueList = ...;
for(Double value : valueList) {
    // TODO: 处理value
}

3. Get the name of the current method

<span style=
"font-family:Arial;font-size:14px;"
>String methodName = Thread.currentThread().getStackTrace()[
1
].getMethodName(); </span>

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