package javaSE2;
public class StringBuilder {
public static void main(String[] args){
StringBuilder builder = new StringBuilder();
builder.append("a");
}
}
报错是The method append(String) is undefined for the type StringBuilder
package javaSE2;
public class StringBuilder {
public static void main(String[] args){
StringBuilder builder = new StringBuilder();
builder.append("a");
}
}
报错是The method append(String) is undefined for the type StringBuilder
你定义的是一个同名的StringBuilder类
你new实例化也是这个类.但是你这个类没有.append方法.
你应该用的是java.lang里面提供StringBuilder类
修改一,将你的public class StringBuilder类名改为其他类名(如:StringBuilderXXX);
修改二,java.lang.StringBuilder builder = new java.lang.StringBuilder();这样用就有append方法了
任选一个修改即可