复杂对象的输出--定制toString

先来看一个类

public class ComplexObject implements Serializable {

    private static final long         serialVersionUID = -3986831089858789914L;

    private int                    id;

    private String                    name;

    private AccountTypeEnum           type;

    private String                    national;

    private Date                      gmtCreate;

    private Date                      gmtModified;

    private String                    memo;

    private SubType1                 subType1;

    private List<SubType2>            subType2List;

    private final Map<String, String> infoMap          = new HashMap<String, String>();

}

 复杂对象ComplexObject包含了如下属性：

1基本类型：String、枚举、int

2Date对象

3.自定义对象

4.List集合

5.Map对象

 

如果输出的对象更易看清每一个字段的值呢

1.ToStringBuilder的默认style

调用方式：ToStringBuilder.reflectionToString(object)

 

2.ToStringBuilder的默认MULTI_LINE_STYLE

调用方式：ToStringBuilder.reflectionToString(customer,ToStringStyle.MULTI_LINE_STYLE)

 

3.自定制toString方法

 private void getFields(Object obj, StringBuffer str, int level, boolean isListElement)
                                                                                                  throws IllegalArgumentException,
                                                                                                  IllegalAccessException {
        if (obj == null) {
            return;
        }

        Class clazz = obj.getClass();
        if (clazz == ComplexObject.class) {
            str.append(" " + clazz.getSimpleName() + "\n");
            level++;
        }

        // 当前输入对象为List元素
        if (isListElement) {
            for (int i = 0; i < level; i++) {
                str.append("     ");
            }
            str.append("└—— " + clazz.getSimpleName() + "\n");
            level++;
            isListElement = false;
        }

        // 获得当前输入对象声明的所有属性
        Field[] fieldArray = clazz.getDeclaredFields();
        for (Field field : fieldArray) {
            for (int i = 0; i < level; i++) {
                str.append("     ");
            }
            field.setAccessible(true);
            // 当前属性未赋值
            if (field.get(obj) == null) {
                str.append("└—— " + field.getName() + " = " + field.get(obj) + "\n");
            } else if (field.getType() == SubType1.class 
                       || field.getType() == SubType2.class ) {
                str.append("└—— " + field.getName() + "\n");
                getFields(field.get(obj), str, level + 1, false);
            } else if (field.getType() == List.class) {
                str.append("└—— " + field.getName() + "\n");
                List list = (List) field.get(obj);
                for (Object object : list) {
                    getFields(object, str, level + 1, true);
                }
            } else if (field.getType() == Map.class) {
                str.append("└—— " + field.getName() + "\n");
                level++;
                Map map = (Map) field.get(obj);
                Set keySet = map.keySet();
                for (Object key : keySet) {
                    for (int i = 0; i < level; i++) {
                        str.append("     ");
                    }
                    str.append("└—— " + key + " = " + map.get(key) + "\n");
                }
            } else if (field.getType() == Date.class) {
                str.append("└—— "
                           + field.getName()
                           + " = "
                           + new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
                               .format((Date) field.get(obj)) + "\n");
            }
            else {
                str.append("└—— " + field.getName() + " = " + field.get(obj) + "\n");
            }
        }

    }

 调用方式：

public String toString() {
        StringBuffer str = new StringBuffer("\n----------------------\n");
        try {
            this.getFields(this, str, 0, false);
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        str.append("----------------------\n");
        return str.toString();
    }

输出结构：

 

----------------------
 ComplexObject
     └—— serialVersionUID = -3986831089858789914
     └—— id= 123
     └—— name = ss
     └—— type = PRIVATE_ACCOUNT
     └—— national = null
     └—— createStatus = OPEN
     └—— enableStatus = CAN_USE
     └—— gmtCreate = 2008-09-18 17:42:27
     └—— gmtModified = null
     └—— memo = null
     └—— subType1List
          └—— SubType1
               └—— SubType1属性1= 2088102000419591
               └—— SubType1属性2 = 2
               └—— SubType1属性3 = 3
               └—— SubType1属性4 = 4
               └—— SubType1属性5 = 5        
     └—— SubType2
          └—— SubType2属性1= 1
          └—— SubType2属性2= 2
          └—— SubType2属性3= 3
          └—— SubType2属性4= 4
     └—— infoMap
           └—— key1= value1
           └—— key2= value2
           └—— key3= value3
           └—— key4= value4

使用反射，支持任意对象类型嵌套