在给变量赋值之后，变量仍然为null [英] variable is still null after I assign a value to it JAVA

问题描述

public void crearCliente() {

    int i, k, j, l;
    registro r = new registro();
    k = lr.getSize();

    for (i = 0; i < k; i++) {
        r = lr.get(i);
        l = r.getSize();

        String contenido[] = new String[8];
        for (j = 0; j < l; j++) {
            contenido[j] = r.getCampoR(j);
            //System.out.println(contenido[j]);
        }
        c1 = new Cliente(contenido[0], contenido[1], contenido[2], contenido[3], contenido[4], contenido[5], contenido[6], contenido[7]);
        c1.verCliente();}

在这段代码中，最后，我为c1分配了一个值，但是当我打印它时，我在所有c1字段中都得到了null.我为Cliente类写下了代码.我想打印我给c1的所有值，但是我不知道为什么在所有字段中都打印null.我使用调试器跟踪代码，直到将所有值分配给新变量的句子都正确为止.

In this code, at the end,I assign a value to c1, but when I print it i get null in all the c1 fields. I write my code down for the class Cliente. I want to print all the values i gave to c1 but i do not know why it print null in all the fields. I follow the code using the debugger and everything is right until the sentences which assign all the values to the new variable.

public class Cliente {

private String Id_cliente;
private String Cod_postal;
private String Numero;
private String Calle;
private String Provincia;
private String Poblacion;
private String Telefono;
private String Apellidos;

public Cliente(String idc, String cp, String num, String cal, String prov, String pob, String tlf, String aps){

    idc = Id_cliente;
    cp = Cod_postal;
    num = Numero;
    cal = Calle;
    prov = Provincia;
    pob = Poblacion;
    tlf = Telefono;
    aps = Apellidos;

}

public void verCliente(){

   System.out.println("Id_cliente: "+ Id_cliente);
   System.out.println("Codigo postal: "+ Cod_postal);
   System.out.println("Numero: "+ Numero);
   System.out.println("Calle: "+ Calle);
   System.out.println("Provincia: "+ Provincia);
   System.out.println("Poblacion: "+ Poblacion);
   System.out.println("Telefono: "+ Telefono);
   System.out.println("Apellidos: "+ Apellidos);

}

}

推荐答案

您应更改此

idc = Id_cliente;

到

Id_cliente = idc;. 

您正在为方法参数而不是字段分配值.相同的情况适用于构造函数 Cliente 中的所有参数.

You are assigning a values to your method parameters, rather than fields. Same applies to all of the parameters in your constructor Cliente.

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