打印类中的所有变量值

Question

我有一堂课，其中包含有关Person的信息，看起来像这样：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toString()返回this.name +" - "+ this.locations + ...所有变量。我试图使用反射来实现它，如该问题所示，但是我无法打印实例变量。解决此问题的正确方法是什么？

Answer 1

从实现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();

}

Answer 2

通用toString（）一排，使用反射和样式自定义：

import org.apache.commons.lang3.builder.ReflectionToStringBuilder;

import org.apache.commons.lang3.builder.ToStringStyle;

...

public String toString()

{

  return ReflectionToStringBuilder.toString(this, ToStringStyle.SHORT_PREFIX_STYLE);

}