在java代码中给mysql必备字段设置默认值

第一种方式

mybatisplus提供的@TableField注解直接可以解决时间默认值的问题

@TableField注解配合FieldFill 根据新增修改不同操作设置默认值

// 字段添加填充内容
@ApiModelProperty(value = "创建时间")
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
@TableField(value = "create_date", fill = FieldFill.INSERT)
private LocalDateTime createDate;@ApiModelProperty(value = "修改时间")
@JsonFormat(shape = JsonFormat.Shape.STRING, pattern = "yyyy-MM-dd HH:mm:ss")
@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
@TableField(value = "modify_date", fill = FieldFill.INSERT_UPDATE)
private LocalDateTime modifyDate;

第二种方式

自定义反射工具类ReflectUtil，统一处理mysql必备字段赋值

比第一种方式的好处是可以根据项目的权限控制，获取当前登录人信息，记录当前登录人为操作人

import java.beans.PropertyDescriptor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeanUtils;
import org.springframework.util.CollectionUtils;public class ReflectUtil {private static final Logger log = LoggerFactory.getLogger(ReflectUtil.class);private ReflectUtil() {}public static <T> void setFieldValueWhenExists(T t, String fieldName, Object value) {setFieldValueWhenExists(t, fieldName, value, false);}public static <T> void setFieldValue(T t, String fieldName, Object value) {setFieldValueWhenExists(t, fieldName, value, true);}public static <T> void setFieldValueWhenExists(T t, String fieldName, Object value, boolean override) {try {List<Field> fields = getField(t.getClass(), fieldName);if (CollectionUtils.isEmpty(fields)) {return;}Iterator var5 = fields.iterator();while(var5.hasNext()) {Field field = (Field)var5.next();setSingleFieldValue(t, field, fieldName, value, override);}} catch (Exception var7) {log.error("反射设置属性值失败", var7);}}private static <T> void setSingleFieldValue(T t, Field field, String fieldName, Object value, boolean override) throws Exception {int typeCode = field.getModifiers();Object oldValue = null;Method method;if (Modifier.isPublic(typeCode)) {oldValue = field.get(t);} else {method = t.getClass().getMethod("get" + getMethodName(fieldName));oldValue = method.invoke(t);}if (oldValue == null || override) {if (Modifier.isPublic(typeCode)) {field.set(t, value);} else {method = t.getClass().getMethod("set" + getMethodName(fieldName), value != null ? value.getClass() : field.getType());method.invoke(t, value);}}}private static String getMethodName(String fieldName) throws Exception {byte[] items = fieldName.getBytes();items[0] = (byte)((char)items[0] - 97 + 65);return new String(items);}public static List<Field> getField(Class<?> clazz, String filedName) {if (clazz != null && !StringUtils.isEmpty(filedName)) {List<Field> fields = new ArrayList();for(Class<?> tempClass = clazz; tempClass != null; tempClass = tempClass.getSuperclass()) {fields.addAll(Arrays.asList(tempClass.getDeclaredFields()));}return (List)(CollectionUtils.isEmpty(fields) ? fields : getFieldByName(fields, filedName));} else {throw new IllegalArgumentException("params is illegal");}}public static List<Field> getFieldByName(List<Field> fields, String fieldName) {if (fields != null && fields.size() != 0 && !StringUtils.isEmpty(fieldName)) {List<Field> foundFields = new ArrayList();Iterator var3 = fields.iterator();while(var3.hasNext()) {Field field = (Field)var3.next();String name = field.getName();if (fieldName.equals(name)) {foundFields.add(field);}}return foundFields;} else {throw new IllegalArgumentException("params is illegal");}}public static boolean isFiledWithName(Field field, String fieldName) {if (field != null && !StringUtils.isEmpty(fieldName)) {return fieldName.equals(field.getName());} else {throw new IllegalArgumentException("params is illegal");}}public static String getFieldValueByFieldName(String fieldName, Object object) {try {Field field = object.getClass().getDeclaredField(fieldName);field.setAccessible(true);Object hisValue = field.get(object);return null == hisValue ? "" : hisValue.toString();} catch (Exception var4) {return "";}}public static Object getFieldValue(Object obj, String fieldName, boolean isTrimSpace) {Object val = null;if (obj instanceof Map) {val = ((Map)obj).get(fieldName);} else {val = getProperty(obj, fieldName);}if (val != null && val instanceof String && isTrimSpace) {val = ((String)val).trim();if ("".equals(val)) {val = null;}}return val;}private static Object getProperty(Object obj, String fieldName) {PropertyDescriptor pd = getPropertyDescriptor(obj.getClass(), fieldName);if (pd != null && pd.getReadMethod() != null) {try {return pd.getReadMethod().invoke(obj, (Object[])null);} catch (Exception var4) {throw new RuntimeException(var4);}} else {throw new IllegalStateException("In class" + obj.getClass() + ", no getter method found for field '" + fieldName + "'");}}private static PropertyDescriptor getPropertyDescriptor(Class<?> clazz, String propertyName) {return BeanUtils.getPropertyDescriptor(clazz, propertyName);}
}

自定义类，重写相关方法，设置默认值

public abstract class BaseService<M extends BaseMapper<T>, T> extends ServiceImpl<M, T> {protected Log log = LogFactory.getLog(this.getClass());@Autowiredprotected M baseMapper;public boolean save(T entity) {this.beforeSave(entity);return super.save(entity);}public boolean updateById(T entity) {this.beforeUpdate(entity);return super.updateById(entity);}public boolean auditById(T entity) {this.beforeAudit(entity);return super.updateById(entity);}protected void beforeSave(Object object) {LocalDateTime now = LocalDateTime.now();// 可根据项目中具体情况获取当前登录信息String userLogin = "admin";ReflectUtil.setFieldValue(object, "createBy", userLogin);ReflectUtil.setFieldValue(object, "createDate", now);ReflectUtil.setFieldValue(object, "modifyBy", userLogin);ReflectUtil.setFieldValue(object, "modifyDate", now);}protected void beforeUpdate(Object object) {LocalDateTime now = LocalDateTime.now();String userLogin = "admin";ReflectUtil.setFieldValue(object, "modifyBy", userLogin);ReflectUtil.setFieldValue(object, "modifyDate", now);}protected void beforeAudit(Object object) {LocalDateTime now = LocalDateTime.now();String userLogin = "admin";ReflectUtil.setFieldValue(object, "auditBy", userLogin);ReflectUtil.setFieldValue(object, "auditDate", now);}
}

项目中统一继承BaseService类即可

@Slf4j
@Service
public class UserServiceImpl extends BaseService<UserMapper, User> {
}