从类中打印所有变量值 [英] Printing all variables value from a class

问题描述

我有一个类，其中包含有关人员的信息，如下所示：

I have a class with information about a Person that looks something like this:

public class Contact {
    private String name;
    private String location;
    private String address;
    private String email;
    private String phone;
    private String fax;

    public String toString() {
        // Something here
    }
    // Getters and setters.
}

我想要 toString（）为所有变量返回 this.name + - + this.locations + ... 。我试图使用反射来实现它，如这个问题所示但我无法设法打印实例变量。

I want toString() to return this.name +" - "+ this.locations + ... for all variables. I was trying to implement it using reflection as shown from this question but I can't manage to print instance variables.

解决此问题的正确方法是什么？

What is the correct way to solve this?

推荐答案

从实施toString ：

public String toString() {
  StringBuilder result = new StringBuilder();
  String newLine = System.getProperty("line.separator");

  result.append( this.getClass().getName() );
  result.append( " Object {" );
  result.append(newLine);

  //determine fields declared in this class only (no fields of superclass)
  Field[] fields = this.getClass().getDeclaredFields();

  //print field names paired with their values
  for ( Field field : fields  ) {
    result.append("  ");
    try {
      result.append( field.getName() );
      result.append(": ");
      //requires access to private field:
      result.append( field.get(this) );
    } catch ( IllegalAccessException ex ) {
      System.out.println(ex);
    }
    result.append(newLine);
  }
  result.append("}");

  return result.toString();
}

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