spring data jpa 之 通用接口

　　　园主这一阵子接到一个需求，就是将spring data jpa再进行封装，实现通过调用一个baseRepository，来实现每个类的增删改查操作，结合spring data jpa 原有的便捷操作，实现快捷开发，话不多说，上代码！

1 首先编写通用接口

package com.hhsj.repository;

import com.hhsj.base.Params;
import com.hhsj.base.Result;
import org.springframework.data.jpa.repository.JpaRepository;

import java.util.LinkedHashMap;
import java.util.List;

public interface baseRepository<T ,ID>{

    /**
     * 保存数据对象
     * @param entity
     * @return
     */
    Boolean save(T entity);
    /**
     * 根据id查询
     * @param clazz
     * @param id
     * @return
     */
    T findByid(Class<T> clazz,ID id);
    /**
     * 根据表名，字段，参数查询，拼接sql语句
     * @param  clazz 表的class
     * @param filed 字段名
     * @param o 字段参数
     * @return
     */
    List<T> findByField(Class<T> clazz, String filed, Object o);

    /**
     * 多个字段的查询
     * @param clazz 表的class
     * @param map 将你的字段传入map中
     * @return
     */
    List<T> findByMoreFiled(Class<T> clazz,LinkedHashMap<String,Object> map);

    /**
     * 根据表的id删除数据
     * @param  entity
     */
    Boolean delete(T entity);
    /**
     * 更新对象
     * @param e
     * @return
     */
    Boolean update(T e ,ID id);
    /**
     * 根据条件查询总条数返回object类型
     * @param clazz 表的class
     * @param map 传入参数放入map中
     * @return
     */
    Integer findCount(Class<T> clazz, LinkedHashMap<String,Object> map);

    /**
     * 通过传入自定义参数查询
     * @param clazz
     * @param params
     * @return
     */
    List<T> findByParams(Class<T> clazz , Params params);

    /**
     * 根据id删除
     * @param clazz
     * @param id
     * @return
     */
    Boolean deleteById(Class<T> clazz, ID id);

    /**
     * 通过id集合批量删除
     * @param clazz
     * @param ids
     * @return
     */
    Boolean deleteByIds(Class<T> clazz , List<ID> ids);
}

BaseRepository

2 通用接口的实现类

package com.hhsj.repository;

import com.hhsj.base.BeanUtils;
import com.hhsj.base.Params;
import org.springframework.stereotype.Repository;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;
import javax.transaction.Transactional;
import java.lang.reflect.Field;
import java.util.*;

@Repository
public class BaseRepositoryImpl<T,ID> implements baseRepository<T,ID>{

    @PersistenceContext
    private EntityManager entityManager;

    @Override
    @Transactional
    public Boolean save(T entity){
        boolean flag = false;
        try {
            entityManager.persist(entity);
            flag = true;
        }catch (Exception e){
            System.out.println("---------------保存出错---------------");
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public T findByid(Class<T> clazz,ID id) {
        T t = null;
        try {
            t = entityManager.find(clazz, id);
        } catch (Exception e) {
            System.out.println("---------------查询出错---------------");
            e.printStackTrace();
        }
        return t;
    }

    @Override
    public List<T> findByField(Class<T> clazz, String filed, Object value ) {
        String tablename = clazz.getName();
        List<T> list = new ArrayList<>();
        try {
            String sql="from "+tablename+" u WHERE u."+filed+"=?1";
            Query query=entityManager.createQuery(sql);
            query.setParameter(1,value);
            list= query.getResultList();
            entityManager.close();
        }catch (Exception e){
            System.out.println("---------------查询出错---------------");
            e.printStackTrace();
        }
        return list;
    }

    @Override
    @Transactional
    public Boolean deleteById(Class<T> clazz, ID id) {
        Boolean flag = false;
        try {
            String tableName = clazz.getName();
            String sql = "delete from "+tableName+" u WHERE u.id = ?1";
            Query query=entityManager.createQuery(sql);
            query.setParameter(1,id);
            int i = query.executeUpdate();
            if(i != 0){
                flag = true;
            }
            entityManager.close();
        } catch (Exception e) {
            e.printStackTrace();
        }

        return flag;
    }

    @Override
    @Transactional
    public Boolean deleteByIds(Class<T> clazz, List<ID> ids) {
        boolean flag = false;
        List<ID> param = new ArrayList<ID>();
        int index = 1;
        try {
            String tableName = clazz.getName();
            StringBuilder sql = new StringBuilder("delete from "+tableName+" u WHERE u.id in (");
            if (ids != null && ids.size() != 0){
                for (ID id : ids) {
                    sql.append("?").append(index).append(",");
                    param.add(id);
                    index ++ ;
                }
            }
            sql.deleteCharAt(sql.length() - 1 );
            sql.append(")");
            Query query=entityManager.createQuery(sql.toString());
            for (int x = 0;x < param.size();x++) {
                query.setParameter(x+1,param.get(x));
            }
            int i = query.executeUpdate();
            if (i != 0){
                flag = true;
            }
            entityManager.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public List<T> findByMoreFiled(Class<T> clazz,LinkedHashMap<String,Object> map) {
        String tablename = clazz.getName();
        List<T> listRe = new ArrayList<>();
        try {
            String sql="from "+tablename+" u WHERE ";
            Set<String> set=null;
            set=map.keySet();
            List<String> list=new ArrayList<>(set);
            List<Object> filedlist=new ArrayList<>();
            int x = 1;
            for (String filed:list){
                sql+="u."+filed+"=?"+x+" and ";
                filedlist.add(filed);
                x++;
            }
            sql=sql.substring(0,sql.length()-4);
            Query query=entityManager.createQuery(sql);
            for (int i=0;i<filedlist.size();i++){
                query.setParameter(i+1,map.get(filedlist.get(i)));
            }
            listRe= query.getResultList();
            entityManager.close();
        }catch (Exception e){
            System.out.println("---------------查询出错---------------");
            e.printStackTrace();
        }
        return listRe;
    }

    @Override
    @Transactional
    public Boolean update(T entity,ID id) {
        boolean flag = false;
        try {
            Object o = entityManager.find(entity.getClass(), id);
            BeanUtils.copyPropertiesExcludeNull(entity,o);
            entityManager.merge(o);
            flag = true;
        } catch (Exception e) {
            System.out.println("---------------查询出错---------------");
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    @Transactional
    public Boolean delete(T entity) {  //entity通过设置id来删除相应数据
        boolean flag=false;
        try {
            entityManager.remove(entityManager.merge(entity));
            flag=true;
        }catch (Exception e){
            System.out.println("---------------删除出错---------------");
            e.printStackTrace();
        }
        return flag;
    }

    @Override
    public Integer findCount(Class<T> clazz, LinkedHashMap<String, Object> map) {
        String tablename = clazz.getName();
        Query query= null;
        Object count = 0;
        try {
            String sql="select count(u) from "+tablename+" u WHERE ";
            Set<String> set=null;
            set=map.keySet();
            List<String> list=new ArrayList<>(set);
            List<Object> filedlist=new ArrayList<>();
            int x = 1;
            for (String filed:list){
                sql+="u."+filed+"=?"+ x +" and ";
                x++;
                filedlist.add(filed);
            }
            sql=sql.substring(0,sql.length()-4);
            query = entityManager.createQuery(sql);
            for (int i=0;i<filedlist.size();i++){
                query.setParameter(i+1,map.get(filedlist.get(i)));
            }
            count = query.getSingleResult();
        } catch (Exception e) {
            System.out.println("---------------查询出错---------------");
            e.printStackTrace();
        }
        return Integer.parseInt(count.toString());
    }

    @Override
    public List<T> findByParams(Class<T> clazz, Params params) {
        String tablename = clazz.getName();
        List<T> listRe = new ArrayList<>();
        //jpa运行时需要的参数
        List param = new ArrayList();
        try {
            StringBuilder sql = new StringBuilder();
            sql.append("from ").append(tablename).append(" u WHERE 1=1 ");
            int index = 0;
            //拼接sql，添加参数集合
            index = concatSqlForObj(index,param, sql, params.getAnd(), params.getAndPara());
            index = concatSqlForObj(index,param, sql, params.getOr(), params.getOrPara());
            index = concatSqlForList(index,param, sql, params.getBetween(), params.getBetweenPara());
            index = concatSqlForObj(index,param, sql, params.getLessThan(), params.getLessThanPara());
            index = concatSqlForObj(index,param, sql, params.getMoreThan(), params.getMoreThanPara());
            index = concatSqlForObj(index,param, sql, params.getLike(), params.getLikePara());
            index = concatSqlForObj(index,param, sql, params.getNotLike(), params.getNotLikePara());
            index = concatSqlForObj(index,param, sql, params.getOrderBy(), params.getOrderByPara());
            index = concatSqlForObj(index,param, sql, params.getNot(), params.getNotPara());

            index = concatSqlForList(index,param, sql, params.getIn(), params.getInPara());
            index = concatSqlForList(index,param, sql, params.getNotIn(), params.getNotInPara());

            Query query=entityManager.createQuery(sql.toString());
            //limit
            if (params.getLimitPara() != null){
                List list = params.getLimitPara().get("limit");
                query.setFirstResult((Integer) list.get(0));
                query.setMaxResults((Integer) list.get(1));
            }
            for (int i=0;i<param.size();i++){
                query.setParameter(i+1,param.get(i));
            }
            listRe= query.getResultList();
            entityManager.close();
        }catch (Exception e){
            System.out.println("---------------查询出错---------------");
            e.printStackTrace();
        }
        return listRe;
    }

    public static int concatSqlForObj(int index,List param ,StringBuilder sql , List<String> symbols , LinkedHashMap<String , Object> params){
        //拼接sql时需要的参数索引
        int index1 = index;
        //取list中的键值对是需要的索引
        int x = 0;
        if (symbols != null && symbols.size() != 0){
            for (String  symbol: symbols) {
                //通过转换list获取键值对
                List<Map.Entry<String, Object>> indexedList = new ArrayList<Map.Entry<String, Object>>(params.entrySet());
                Map.Entry<String, Object> entry = indexedList.get(x);
                String key = entry.getKey();
                Object value = entry.getValue();

                index1 ++ ;
                x++;

                if (symbol.equals("or")){
                    sql.append(" or u.").append(key).append("=?").append(index1);
                }else if(symbol.equals("<")){
                    sql.append(" and u.").append(key).append("<?").append(index1);
                }else if(symbol.equals(">")){
                    sql.append(" and u.").append(key).append(">?").append(index1);
                }else if(symbol.equals("like")){
                    sql.append(" and u.").append(key).append(" like ?").append(index1);
                }else if(symbol.equals("notlike")){
                    sql.append(" and u.").append(key).append(" not like ?").append(index1);
                }else if(symbol.equals("!=")){
                    sql.append(" and u.").append(key).append(" != ?").append(index1);
                }
                else if(symbol.equals("orderby")){
                    //val的值可取asc 和 desc
                    sql.append(" ORDER BY ").append(key).append(" ").append(value.toString());
                    return index1;
                }
                else {
                    sql.append(" and u."+key + symbol+"?" + index1);
                }
                param.add(value);
            }
        }
        return index1;
    }

    public static int concatSqlForList(int index,List param ,StringBuilder sql , List<String> symbols , LinkedHashMap<String , List> params){
        //拼接sql时需要的参数索引
        int index1 = index;
        //取list中的键值对是需要的索引
        int x = 0;
        if (symbols != null && symbols.size() != 0){
            for (String  symbol: symbols) {
                //通过转换list获取键值对
                List<Map.Entry<String, List>> indexedList = new ArrayList<Map.Entry<String, List>>(params.entrySet());
                Map.Entry<String, List> entry = indexedList.get(x);
                String key = entry.getKey();
                List value = entry.getValue();

                index1 ++ ;
                x++;

                if(symbol.equals("between")){
                    sql.append(" and u.").append(key).append(" between ?").append(index1).append(" and ?").append(index1 + 1);
                    index1 ++;
                }else if (symbol.equals("in") || symbol.equals("notin")){
                    sql.append(" and u.").append(key);
                    if (symbol.equals("in")){
                        sql.append(" in (?");
                    }else {
                        sql.append(" not in (?");
                    }
                    sql.append(index1);
                    param.add(value.get(0));
                    for (int i = 1 ; i < value.size() ; i++){
                        index1 ++;
                        sql.append(",?").append(index1);
                        param.add(value.get(i));
                    }
                    sql.append(")");
                    return index1;
                }
                param.add(value.get(0));
                param.add(value.get(1));
            }
        }
        return index1;
    }
}

BaseRepositoryImpl

3 多条件查询的参数类

package com.hhsj.base;

import lombok.Data;

import java.util.ArrayList;
import java.util.List;
import java.util.LinkedHashMap;

/**
 * 自定义参数
 */
@Data
public class Params {

    private final List<String> and;
    private final LinkedHashMap<String ,Object> andPara;

    private final List<String> or;
    private final LinkedHashMap<String ,Object> orPara;

    private final List<String> between;
    private final LinkedHashMap<String ,List> betweenPara;

    private final List<String> lessThan;
    private final LinkedHashMap<String ,Object> lessThanPara;

    private final List<String> moreThan;
    private final LinkedHashMap<String ,Object> moreThanPara;

   /* private final List<String> isNull;
    private final LinkedHashMap<String ,Object> isNullPara;

    private final List<String> isNotNull;
    private final LinkedHashMap<String ,Object> isNotNullPara;*/

    private final List<String> like;
    private final LinkedHashMap<String ,Object> likePara;

    private final List<String> notLike;
    private final LinkedHashMap<String ,Object> notLikePara;

    private final List<String> orderBy;
    private final LinkedHashMap<String ,Object> orderByPara;

    private final List<String> not;
    private final LinkedHashMap<String ,Object> notPara;

    private final List<String> in;
    private final LinkedHashMap<String ,List> inPara;

    private final List<String> notIn;
    private final LinkedHashMap<String ,List> notInPara;

    private final List<String> limit;
    private final LinkedHashMap<String ,List> limitPara;

    private Params(Bulider bulider){
        this.and = bulider.and;
        this.andPara = bulider.andPara;
        this.or = bulider.or;
        this.orPara = bulider.orPara;
        this.between = bulider.between;
        this.betweenPara = bulider.betweenPara;
        this.lessThan = bulider.lessThan;
        this.lessThanPara = bulider.lessThanPara;
        this.moreThan = bulider.moreThan;
        this.moreThanPara = bulider.moreThanPara;
        /*this.isNull = bulider.isNull;
        this.isNullPara = bulider.isNullPara;
        this.isNotNull = bulider.isNotNull;
        this.isNotNullPara = bulider.isNotNullPara;*/
        this.like = bulider.like;
        this.likePara = bulider.likePara;
        this.notLike = bulider.notLike;
        this.notLikePara = bulider.notLikePara;
        this.orderBy = bulider.orderBy;
        this.orderByPara = bulider.orderByPara;
        this.not = bulider.not;
        this.notPara = bulider.notPara;
        this.in = bulider.in;
        this.inPara = bulider.inPara;
        this.notIn = bulider.notIn;
        this.notInPara = bulider.notInPara;
        this.limit = bulider.limit;
        this.limitPara = bulider.limitPara;
    }

    public static Params.Bulider builder() {
        return new Params.Bulider();
    }

    public static class Bulider{
        private List<String> and;
        private LinkedHashMap<String ,Object> andPara;

        private List<String> or;
        private LinkedHashMap<String ,Object> orPara;

        private List<String> between;
        private LinkedHashMap<String ,List> betweenPara;

        private List<String> lessThan;
        private LinkedHashMap<String ,Object> lessThanPara;

        private List<String> moreThan;
        private LinkedHashMap<String ,Object> moreThanPara;

       /* private List<String> isNull;
        private LinkedHashMap<String ,Object> isNullPara;

        private List<String> isNotNull;
        private LinkedHashMap<String ,Object> isNotNullPara;*/

        private List<String> like;
        private LinkedHashMap<String ,Object> likePara;

        private List<String> notLike;
        private LinkedHashMap<String ,Object> notLikePara;

        private List<String> orderBy;
        private LinkedHashMap<String ,Object> orderByPara;

        private List<String> not;
        private LinkedHashMap<String ,Object> notPara;

        private List<String> in;
        private LinkedHashMap<String ,List> inPara;

        private List<String> notIn;
        private LinkedHashMap<String ,List> notInPara;

        private List<String> limit;
        private LinkedHashMap<String ,List> limitPara;

        public Bulider Euqal(String key , Object value){
            this.and = new ArrayList<>();
            this.andPara = new LinkedHashMap<>();
            this.and.add("=");
            this.andPara.put(key,value);
            return this;
        }

        public Bulider Or(String key , Object value){
            this.or = new ArrayList<>();
            this.orPara = new LinkedHashMap<>();
            this.or.add("or");
            this.orPara.put(key,value);
            return this;
        }

        public Bulider Between(String key , Object value1 , Object value2){
            this.between = new ArrayList<>();
            this.betweenPara = new LinkedHashMap<>();
            List value = new ArrayList();
            value.add(value1);
            value.add(value2);
            this.between.add("between");
            this.betweenPara.put(key,value);
            return this;
        }

        public Bulider LessThan(String key , Object value){
            this.lessThan = new ArrayList<>();
            this.lessThanPara = new LinkedHashMap<>();
            this.lessThan.add("<");
            this.lessThanPara.put(key,value);
            return this;
        }

        public Bulider MoreThan(String key , Object value){
            this.moreThan = new ArrayList<>();
            this.moreThanPara = new LinkedHashMap<>();
            this.moreThan.add(">");
            this.moreThanPara.put(key,value);
            return this;
        }

        /*public Bulider IsNull(String key , Object value){
            this.isNull = new ArrayList<>();
            this.isNullPara = new LinkedHashMap<>();
            this.isNull.add("isnull");
            this.isNullPara.put(key,value);
            return this;
        }

        public Bulider IsNotNull(String key , Object value){
            this.isNotNull = new ArrayList<>();
            this.isNotNullPara = new LinkedHashMap<>();
            this.isNotNull.add("isnotnull");
            this.isNotNullPara.put(key,value);
            return this;
        }*/

        public Bulider Like(String key , Object value){
            this.like = new ArrayList<>();
            this.likePara = new LinkedHashMap<>();
            this.like.add("like");
            this.likePara.put(key,value);
            return this;
        }

        public Bulider NotLike(String key , Object value){
            this.notLike = new ArrayList<>();
            this.notLikePara = new LinkedHashMap<>();
            this.notLike.add("notlike");
            this.notLikePara.put(key,value);
            return this;
        }

        public Bulider OrderBy(String key , Object value){
            this.orderBy = new ArrayList<>();
            this.orderByPara = new LinkedHashMap<>();
            this.orderBy.add("orderby");
            this.orderByPara.put(key,value);
            return this;
        }

        public Bulider NotEqual(String key , Object value){
            this.not = new ArrayList<>();
            this.notPara = new LinkedHashMap<>();
            this.not.add("!=");
            this.notPara.put(key,value);
            return this;
        }

        public Bulider In(String key , Object ... values){
            this.in = new ArrayList<>();
            this.inPara = new LinkedHashMap<>();
            List list = new ArrayList();
            for (Object value : values) {
                list.add(value);
            }
            this.in.add("in");
            this.inPara.put(key,list);
            return this;
        }

        public Bulider NotIn(String key , Object ... values){
            this.notIn = new ArrayList<>();
            this.notInPara = new LinkedHashMap<>();
            List list = new ArrayList();
            for (Object value : values) {
                list.add(value);
            }
            this.notIn.add("notin");
            this.notInPara.put(key,list);
            return this;
        }

        public Bulider Limit(Integer value1 , Integer value2){
            this.limit = new ArrayList<>();
            this.limitPara = new LinkedHashMap<>();
            List<Integer> list = new ArrayList();
            list.add(value1);
            list.add(value2);
            this.limit.add("limit");
            this.limitPara.put("limit",list);
            return this;
        }

        public Params build() {
            return new Params(this);
        }
    }

}

Params

4 我的测试类

package com.hhsj.controller;

import com.hhsj.base.Params;
import com.hhsj.base.Result;
import com.hhsj.entity.DevUser;
import com.hhsj.repository.BaseRepositoryImpl;
import com.hhsj.service.impl.DevUserServiceImpl;
import com.sun.org.apache.xml.internal.security.keys.keyresolver.implementations.PrivateKeyResolver;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.*;

@RestController
public class UserController {
    @Autowired
    private BaseRepositoryImpl baseRepository;

    @GetMapping("/cs/save")
    public Boolean csSave(){
        DevUser devUser = new DevUser();
        devUser.setUsername("xxasdasdasdasdasdasdasd");
        devUser.setPassword("dddfadadadasdasd");
        return baseRepository.save(devUser);
    }

    @GetMapping("/cs/findById")
    public DevUser csF(){
        return (DevUser) baseRepository.findByid(DevUser.class,5);
    }

    @GetMapping("/cs/delbyid")
    public Boolean csDelById(){
        return baseRepository.deleteById(DevUser.class,5);
    }

    @GetMapping("/cs/findByField")
    public List<DevUser> csFindByField(){
        return baseRepository.findByField(DevUser.class,"username","1");
    }

    @GetMapping("/cs/delByIds")
    public boolean csdelByIds(){
        List<Integer> list = new ArrayList<>();
        list.add(8);
        list.add(9);
        return baseRepository.deleteByIds(DevUser.class,list);
    }

    @GetMapping("/cs/findByFields")
    public List<DevUser> csFindByFields(){
        LinkedHashMap map = new LinkedHashMap();
        map.put("username","12");
        map.put("password","dddf");
        return baseRepository.findByMoreFiled(DevUser.class,map);
    }

    @GetMapping("/cs/del")
    public Boolean csDel(){
       DevUser devUser = new DevUser();
       devUser.setId(6);
        return baseRepository.delete(devUser);
    }

    @GetMapping("/cs/upd")
    public Boolean csUpd(){
        DevUser devUser = new DevUser();
        devUser.setId(3);
        devUser.setUsername("123345567qweqwwwqe");
        devUser.setPassword("asdaslkdaksdfviosdhfgsdbfkjhdasiofhasdfbdasihgo");
        return baseRepository.update(devUser,devUser.getId());
    }

    @GetMapping("/cs/getCount")
    public Integer csgetCount(){
        LinkedHashMap map = new LinkedHashMap();
        map.put("username","1");
        return baseRepository.findCount(DevUser.class,map);
    }

    @GetMapping("/cs/findByParm")
    public List<DevUser> csfindByParm(){
        Params build = Params.builder().Euqal("password","wqeq").Like("username","%q%").OrderBy("id","desc").build();
        return baseRepository.findByParams(DevUser.class, build);
    }
}

UserController

4 yml文件

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 12345
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    show-sql: true

4 附上通用的Result

package com.hhsj.base;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import lombok.Data;

/**
 * @author cnyuchu@gmail.com
 * @date 2018/11/8 9:27
 */
@Data
public class Result<T> {

    private final String result;

    private final Integer code;

    private final String message;

    private final T data;

    private Result(Builder<T> builder) {
        this.result = builder.result;
        this.code = builder.code;
        this.message = builder.message;
        this.data = builder.data;
    }

    public static<T> Result.Builder<T> builder() {
        return new Result.Builder<>();
    }

    public static class Builder<T> {
        private String result;

        private Integer code;

        private String message;

        private T data;

        public Builder<T> code(Integer code) {
            this.code = code;
            return this;
        }

        public Builder<T>  message(String message) {
            this.message = message;
            return this;
        }

        public Builder<T>  result(String result) {
            this.result = result;
            return this;
        }

        public Builder<T>  success() {
            this.result = "SUCCESS";
            this.code = 200;
            return this;
        }

        public Builder<T>  fail() {
            this.result = "FAILURE";
            this.code = 500;
            return this;
        }

        public Builder<T>  data(T data) {
            this.data = data;
            return this;
        }

        public Result<T> build() {
            return new Result<>(this);
        }
    }

    @JsonIgnore
    public Boolean isFailed(){
        return this.code==500;
    }
}

Result

5 自定义的beanUtils工具类，可复制不为null的属性

package com.hhsj.base;

import org.springframework.beans.BeanWrapper;
import org.springframework.beans.BeanWrapperImpl;
import org.springframework.beans.BeansException;

import java.util.HashSet;
import java.util.Set;

/**
 * BeanUtils
 *
 * @author zhuyoufeng
 */
public class BeanUtils extends org.springframework.beans.BeanUtils {

    public static String[] getNullPropertyNames(Object source) {
        final BeanWrapper src = new BeanWrapperImpl(source);
        java.beans.PropertyDescriptor[] pds = src.getPropertyDescriptors();

        Set<String> emptyNames = new HashSet<String>();
        for (java.beans.PropertyDescriptor pd : pds) {
            Object srcValue = src.getPropertyValue(pd.getName());
            if (srcValue == null) emptyNames.add(pd.getName());
        }
        String[] result = new String[emptyNames.size()];
        return emptyNames.toArray(result);
    }

    public static void copyPropertiesExcludeNull(Object source, Object target) throws BeansException {
        org.springframework.beans.BeanUtils.copyProperties(source, target, getNullPropertyNames(source));
    }
}

BeanUtils

今天的代码就这么多了，有问题一起探讨，谢谢各位。

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