getConstructor、getDeclaredConstructor区别

getDeclaredConstructor：返回指定参数类型、所有声明的（包括private）构造函数

getConstructor：返回指定参数类型、具有public访问权限的构造函数

1、

/**

     * Returns a Constructor object which represents the constructor matching the given parameter types that is declared by the class represented by this Class.
     * Class[] null is equivalent to the empty array.
     */
    @SuppressWarnings("unchecked")

public Constructor<T> getDeclaredConstructor(Class<?>... parameterTypes)

2、

    /**
     * Returns a Constructor object which represents the public constructormatching the given parameter types.
     * Class[] null is equivalent to the empty array.
     *
     * Use getDeclaredConstructor if you don't want to search superclasses.
     */
    @SuppressWarnings("unchecked")
    public Constructor<T> getConstructor(Class<?>... parameterTypes) throws NoSuchMethodException

getDeclaredConstructor：返回指定参数类型、所有声明的（包括private）构造函数

getConstructor：返回指定参数类型、具有public访问权限的构造函数

Class中，有其他类似方法。

反射获取private构造方法

package com.test;

A {

private String str;

public A() { str = "first"; }

private A(String str) { this.str = str; }

public String getStr() { return str; }

}

void main(String[] args) {

Class cls = Class.forName("com.test.A");

Class[] paramsType = { String.class };

Object[] params = { "second" };

Constructor con = cls.getDeclaredConstructor(paramsType);

con.setAccessible(true);

A a = (A)con.newinstanct(params);

a.getStr();// second

}