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反射报错java.lang.IllegalArgumentException: wrong number of arguments 

class Person{
    private String name ;
    private String sex ;
    public  Person(){
        System.out.println("c");}
    public  Person(String c1){
         this.name =c1;
        System.out.println("c1"+c1);}
    public  Person(String c1,String c2){
        this.name =c1;
        this.sex =c2;
        System.out.println("c1"+c1 +"c2"+c2);}

</span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> String getName() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> name;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> setName(String name) {
    </span><span style="color: rgba(0, 0, 255, 1)">this</span>.name =<span style="color: rgba(0, 0, 0, 1)"> name;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span><span style="color: rgba(0, 0, 0, 1)"> String getSex() {
    </span><span style="color: rgba(0, 0, 255, 1)">return</span><span style="color: rgba(0, 0, 0, 1)"> sex;
}

</span><span style="color: rgba(0, 0, 255, 1)">public</span> <span style="color: rgba(0, 0, 255, 1)">void</span><span style="color: rgba(0, 0, 0, 1)"> setSex(String sex) {
    </span><span style="color: rgba(0, 0, 255, 1)">this</span>.sex =<span style="color: rgba(0, 0, 0, 1)"> sex;
}



}    

 public  static  void  main(String [] args){
        try {
            Class<?> clazz = Class.forName("com.leeeason.miaosha.Person") ; // 取得 Class 对象
            Constructor<?>[] constructors = clazz.getConstructors();
            System.out.print(constructors.length);
            Object o = constructors[0].newInstance();} catch (Exception e) {e.printStackTrace();
        }

}</span></pre>

报错 java.lang.IllegalArgumentException: wrong number of arguments

因为构造函数取值的时候是从下往上 从 0 开始 

  public  static  void  main(String [] args){
        try {
            Class<?> clazz = Class.forName("com.leeeason.miaosha.Person") ; // 取得 Class 对象
            Constructor<?>[] constructors = clazz.getConstructors();
            //System.out.print(constructors.length);
            //修改后
            Object o = constructors[2].newInstance();} catch (Exception e) {e.printStackTrace();
        }

}</span></pre>

返回成功