为类快速赋值

package com.jareny.java.anno;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.Date;

// 设置赋值的数据类型
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface SetData {
    String setString() default "";
    double setDouble() default 0.0;
    int setInteger() default 1;
    long setLong() default 1L;
}

　　

package com.jareny.java.anno;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

// 设置日期的数据类型
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface SetDate {
    String setString() default  "1970-01-01";
}

　　

package com.jareny.java.model;

import com.jareny.java.anno.SetData;
import com.jareny.java.anno.SetDate;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;

// 为用户类快速赋值
public class UserInfo {
    @SetData(setString="userId")
    private String userId;
    @SetData(setInteger=30)
    private Integer age;
    @SetData(setDouble=30000.0)
    private Double salary;
    @SetData(setLong=5000L)
    private Long  bath;
    @SetDate(setString="1989-01-01")
    private String  bathDate;

    @Override
    public String toString() {
        return "UserInfo{" +
                "userId='" + userId + '\'' +
                ", age=" + age +
                ", salary=" + salary +
                ", bath=" + bath +
                ", bathDate='" + bathDate + '\'' +
                '}';
    }

    // 为用户类快速赋值
    public static List<UserInfo> getUserInfoList() throws Exception {
        Class<UserInfo> userInfoClass = UserInfo.class;
        Field[] declaredFields = userInfoClass.getDeclaredFields();
        List<UserInfo> list = new ArrayList<>();
        for (int index=0;index<50;index++){
            UserInfo userInfo = userInfoClass.newInstance();
            for (Field field:declaredFields){
                field.setAccessible(true);
                String name = field.getType().getName();
                // 判断是否有 @SetData 注解
                if(field.isAnnotationPresent(SetData.class)){
                    // 获取注解
                    SetData annotation = field.getAnnotation(SetData.class);
                    // 根据类型赋值操作
                    if("java.lang.String".equals(name)){
                        field.set(userInfo,annotation.setString()+index);
                    }
                    if("java.lang.Double".equals(name)){
                        field.set(userInfo,annotation.setDouble()+index);
                    }
                    if("java.lang.Integer".equals(name)){
                        field.set(userInfo,annotation.setInteger()+index);
                    }
                    if("java.lang.Long".equals(name)){
                        field.set(userInfo,annotation.setLong()+index);
                    }
                }
                // 判断是否有 @SetDate 注解
                if(field.isAnnotationPresent(SetDate.class)){
                    SetDate annotation = field.getAnnotation(SetDate.class);
                    if("java.lang.String".equals(name)){
                        field.set(userInfo,annotation.setString()+index);
                    }
                }
            }
            System.out.println(userInfo.toString());
            list.add(userInfo);
        }
        return list;
    }

    public static void main(String[] args) throws Exception {
        getUserInfoList();
    }
}