Entity与Entity之间的相互转化

一。两个实体类的属性名称对应之间的转化

1.两个实体类

public class Entity1 {

    private Integer id;

    private String name;

    private Integer age;

    private byte sex;

       // get/set

}

public class Entity2 {

    private String name;

    private Double sal;

    private Integer age;

        // get/set

}

2。Entity2Entity 转化类

public class Entity2Entity {

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

        Entity1 en = new Entity1(1, "zcj", 18, (byte)1);

        Object parse = parse(en,new Entity2());

        System.out.println(parse);

    }

    public static <T, F> F parse(T src, F target) throws Exception{

        Method[] srcMethods = src.getClass().getMethods();

        Method[] targetMethod = target.getClass().getMethods();

        for(Method m : srcMethods) {

            if(m.getName().startsWith("get")) {

                Object result = m.invoke(src);

                for(Method mm : targetMethod) {

                    if(mm.getName().startsWith("set") && mm.getName().substring(3).

                            equals(m.getName().substring(3))) {

                        mm.invoke(target,result);

                    }

                }

            }

        }

        return target;

    }

}

3。运行结果

PersonDto [personId=1, personName=zcj, personAge=12, sal=12.0]

二。基于实体类中要转化的get方法或者属性进行转化

package com.entity.demo3;

import java.lang.reflect.Field;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import com.entity.demo.Entity1;

import com.entity.demo.Entity2;

public class EntityUtil {

    public static void main(String[] args) {

        Entity1 src = new Entity1(1, "zcj", 18, (byte)1);

        Entity2 target = new Entity2();

//        target = entity2entityByMethod(src,target);

        target = entity2entityByField(src,target);

        System.out.println(target);

    }

    // 首字母转大写

    public static String firstChartToUpper(String str) {

        if (Character.isUpperCase(str.charAt(0))) {

            return str;

        }

        StringBuffer sb = new StringBuffer();

        return sb.append(Character.toUpperCase(str.charAt(0))).append(str.substring(1)).toString();

    }

    /**

     * 基于实体类中要转化的get方法获取

     * @param src

     * @param target

     * @return

     */

    public static <T, F> F entity2entityByMethod(T src, F target) {

        Field[] targetFields = target.getClass().getDeclaredFields();

        for (Field field : targetFields) {

            try {

                Method method = src.getClass().getMethod("get" + firstChartToUpper(field.getName()));

                Object value = method.invoke(src);

                field.setAccessible(true);

                field.set(target, value);

            } catch (Exception e) {

                continue;

            }

        }

        return target;

    }

    /**

     * 基于实体类中属性进行转换

     * @param src

     * @param target

     * @return

     */

    public static <T, F> F entity2entityByField(T src, F target) {

        Field[] srcFields = src.getClass().getDeclaredFields();

        Class<? extends Object> class1 = target.getClass();

        for (Field field : srcFields) {

            try {

                field.setAccessible(true);

                Object value = field.get(src);

                if(value == null) {

                    continue;

                }

                Method mm = class1.getMethod("set"+firstChartToUpper(field.getName()),value.getClass());

                mm.invoke(target, value);

            } catch (Exception e) {

                e.printStackTrace();

                continue;

            }

        }

        return target;

    }

}

三。利用反射+注解进行转化

1.两个实体类

public class Pseron {

	private String perId;

	private String perName;

	private String perAge;

	private Double sal;

	private Integer pno;

}

public class PersonDto {

	@RelMapper(value="perId")

	private String personId;

	@RelMapper(value="perName")

	private String personName;

	@RelMapper(value="perAge")

	private String personAge;

	private Double sal;

}

2.一个自定义的注解

//Target 注解的使用域，FIELD表示使用在属性上面，TYPE表示使用在类上面

@Target({ElementType.FIELD,ElementType.TYPE})

//Retention 设置注解的生命周期 ，这里定义为RetentionPolicy.RUNTIME 非常关键

@Retention(RetentionPolicy.RUNTIME)

@Documented

public @interface Mapper {

    //自定义属性

    String value() default "";

}

3.转化类

public class Entity2Dto {

    public static void main(String[] args){

        Object en2Dto = en2Dto(new Pseron("1","zcj", "12",12.0,null), new PersonDto());

        System.out.println(en2Dto);

    }

    public static Object en2Dto(Object src,Object target) {

        Field[] targetFields = target.getClass().getDeclaredFields();

        Class<? extends Object> srcFields = src.getClass();

        String name;

        for (Field field : targetFields) {

            try {

                field.setAccessible(true);

                // 判断这个字段上是否有相应的注解信息（RelMapper.class）

                if(field.isAnnotationPresent(Mapper.class)){

                    Mapper annotation = field.getAnnotation(Mapper.class);

                    name = annotation.value();

                }else {

                    name = field.getName();

                }

                Field field2 = srcFields.getDeclaredField(name);

                if(field2 != null) {

                    field2.setAccessible(true);

                }

                Object object = field2.get(src);

                field.set(target, object);

            }catch (Exception e) {

                e.printStackTrace();

            }

        }

        return target;

    }

}

巴特西

Entity与Entity之间的相互转化

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