如何在Java中使用其他类的set方法？

Question

How can I set the value of a parameter of class A in class B using the setvarA method of class A ?

public class A{

String varA;
public String getvarA() {
        return varA;
    }
public void setvarA(String varA) {
        this.varA=varA;
    }
}

public class B{

String name = "abc";
A objA = new A();
objA.setvarA(name) ; ## THIS LINES THROWS AN ERROR

}

The error is:

Syntax error on token "name", VariableDeclaratorId expected after this token and Syntax error on token(s), misplaced constructs

Answer 1

public class A{

    String varA;
    public String getvarA() {
        return varA;
    }
    public void setvarA(String varA) {
        this.varA=varA;
    }
}

class B {
    String name = "abc";
    A objA = new A();

    B() {
        objA.setvarA(name);
    }
}

Answer 2

I'm surprised that you only complain about one error.

There are a number of different errors in the code you posted:

• It's String , not string (case is important)
• In the method setvarA , this is wrong: this.varA = var.A; , should have been: this.varA = varA;
• Forgot a semi-colon after String name = "abc"
• Forgot () after new A : A objA = new A();

Answer 3

Revised Code:

public class A{

        String varA; //<-String, not string
        public String getVarA() { 
                return varA;
            }
        public void setVarA(String varA) {
                this.varA=varA; //<- var.A not valid
            }
        }

        class B{
          B(){ //<- Need to write this code in a method or constructor
            String name = "abc"; //<- Semi-colon?
            A objA = new A(); //<- what about parenthesis?
            objA.setVarA(name); //<- Semi-colon?
            }
        }

Answer 4

Here's the corrected and complete code:

public class A{

    String varA;

    public String getvarA() {
        return varA;
    }

    public void setvarA(String varA) {
        this.varA = varA;
    }
}

public class B{

    public B(){
        String name = "abc"
        A objA = new A();
        objA.setvarA(name);
    }
}

Both classes must go in separate files, calles A.java and B.java, of course. Add a main method in one of these files, creating B.

Answer 5

It should be A objA = new A();

• By doing this, you are invoking the constructor of class A which creates the object of class A and assigns the reference variable objA to it .
• Also, objA.setvarA(name); . You missed semicolon here.
• change your string to String . java is case sensitive. String is a class.
• change this.varA=var.A; to this.varA = varA;
• Missing semi colon here String name = "abc" . Change to String name = "abc";
• You have put extra semi colon in setter method. Please correct that.

• Also, you need to call the method from some init block or constructor or a method

  B() { objA.setvarA(name); }