2022-03-06
1112
原创
Hibernate生成SQL语句过程复现
Hibernate生成SQL语句过程复现
文件目录结构：
├── entity -- 数据库的实体类包
| ├── ABean -- 表A对应的数据类型
| ├── BBean -- 表B对应的数据类型
├── dao -- dao包
| ├── impl -- 实现包
| | ├── BaseDaoImpl -- dao层基类
| | ├── ADaoImpl -- dao层A表对应的类
| | ├── BDaoImpl -- dao层B表对应的类
| ├── BaseDao -- dao层基类接口
| ├── ADao -- A类接口
| ├── BDao -- B类接口
先创建好需要用到的bean，即ABean和BBean：
/**
* @Author: 陌攻
* @Description: 表A对应的数据类型
* @Date: 2021/1/6 13:16
* @Modified By:
*/
@Entity
@Table(name="a_table")
public class ABean {
private Long id;
private Date createTime;
private Date updateTime;
@Id
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
@Column(name="CREATE_TIME")
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@Column(name="UPDATE_TIME")
public Date getUpdateTime() {
return updateTime;
}
public void setUpdateTime(Date updateTime) {
this.updateTime = updateTime;
}
}
/**
* @Author: 陌攻
* @Description: 表B对应的数据类型
* @Date: 2021/1/6 13:16
* @Modified By:
*/
@Entity
@Table(name="b_table")
public class BBean {
private Long id;
private Date createTime;
private ABean aBean;
@Id
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
@Column(name="CREATE_TIME")
public Date getCreateTime() {
return createTime;
}
public void setCreateTime(Date createTime) {
this.createTime = createTime;
}
@ManyToOne(cascade=CascadeType.MERGE,optional=true,fetch=FetchType.LAZY)
@JoinColumn(name="id")
public ABean getABean() {
return aBean;
}
public void setABean(ABean aBean) {
this.aBean = aBean;
}
}
创建dao层基类接口：
/**
* @Author: 陌攻
* @Description: dao层基类接口
* @Date: 2021/1/6 13:16
* @Modified By:
*/
public interface BaseDao<T> {
/**
* 创建对应的实体类插入语句
* @param obj
* @return
*/
String createInsertSQLString(T obj);
/**
* 单表修改使用；；生成对应的修改语句
* @param obj
* @return
*/
String createUpdateSQLString(T obj);
/**
* 单表删除使用；；生成对应的删除语句
* @param list
* @return
*/
String createDelSQLString(List<String> list);
}
实现基类接口，下面的代码中为了直观显示直接把sql语句和值拼接在一起输出。
/**
* @Author: 陌攻
* @Description: dao层基类，为了方便不做封装
* @Date: 2021/1/6 13:16
* @Modified By:
*/
public class BaseDaoImpl<T> implements BaseDao<T>{
private Class<T> clazz;
//单表插入使用：生成对应的插入语句
@Override
public String createInsertSQLString(T obj) {
//获取类对象
Class<?> aClass = obj.getClass();
//获取类头部的Table注解
Table table = aClass.getAnnotation(Table.class);
//存放插入语句的字段名
StringBuffer stringBuffer0 = new StringBuffer();
//存放插入语句的插入值
StringBuffer stringBuffer1 = new StringBuffer();
try {
for (int i = 0; i < aClass.getMethods().length; i++) {
Column column = aClass.getMethods()[i].getAnnotation(Column.class);
Id id = aClass.getMethods()[i].getAnnotation(Id.class);
JoinColumn joinColumn = aClass.getMethods()[i].getAnnotation(JoinColumn.class);
//判断否有@Column注解
if (column != null && aClass.getMethods()[i].invoke(obj)!=null) {
stringBuffer0.append(column.name());//列名
Object col = aClass.getMethods()[i].invoke(obj);
if(col instanceof Date){
Date d = (Date) col;
stringBuffer1.append("to_date('");
stringBuffer1.append(DateUtils.getTimeStr(d));//填充值
stringBuffer1.append("', 'yyyy-mm-dd hh24:mi:ss')");
}else{
stringBuffer1.append("'");
stringBuffer1.append(col.toString());//填充值
stringBuffer1.append("'");
}
stringBuffer0.append(",");
stringBuffer1.append(",");
//判断否有@JoinColumn注解
} else if (joinColumn != null && aClass.getMethods()[i].invoke(obj)!=null) {
Object invoke = aClass.getMethods()[i].invoke(obj);
for (int j = 0; j < invoke.getClass().getMethods().length; j++) {
Id annotation3 = invoke.getClass().getMethods()[j].getAnnotation(Id.class);
if (annotation3 != null) {
stringBuffer0.append(joinColumn.name());//列名
stringBuffer1.append("'");
stringBuffer1.append(invoke.getClass().getMethods()[j].invoke(invoke).toString());//填充值
stringBuffer1.append("'");
stringBuffer0.append(",");
stringBuffer1.append(",");
break;
}
}
//判断否有@Id注解
} else if (id != null) {
String name = aClass.getMethods()[i].getName();//"getId"
name = name.substring(3).toUpperCase();//去除"get",转换成大写
stringBuffer0.append(name);//列名
stringBuffer1.append("'");
stringBuffer1.append(UUID.randomUUID().toString().replaceAll("-",""));//填充值
stringBuffer1.append("'");
stringBuffer0.append(",");
stringBuffer1.append(",");
}
}
stringBuffer0.deleteCharAt(stringBuffer0.length() - 1);
stringBuffer1.deleteCharAt(stringBuffer1.length() - 1);
}catch (Exception e){
System.out.println(e.toString());
}
StringBuffer stringBuffer = new StringBuffer();
stringBuffer.append(" insert into ");
stringBuffer.append(table.name());
stringBuffer.append(" ( ");
stringBuffer.append(stringBuffer0);
stringBuffer.append(" ) values ( ");
stringBuffer.append(stringBuffer1);
stringBuffer.append(" )");
return stringBuffer.toString();
// System.out.println("SQL:"+stringBuffer.toString());
}
//单表修改使用；；生成对应的修改语句
@Override
public String createUpdateSQLString(T obj) {
Class<?> aClass = obj.getClass();
Table table = aClass.getAnnotation(Table.class);
StringBuffer stringBuffer0 = new StringBuffer();
String name ="",idValue="";
try {
for (int i = 0; i < aClass.getMethods().length; i++) {
Column column = aClass.getMethods()[i].getAnnotation(Column.class);
Id id = aClass.getMethods()[i].getAnnotation(Id.class);
JoinColumn joinColumn = aClass.getMethods()[i].getAnnotation(JoinColumn.class);
if (column != null && aClass.getMethods()[i].invoke(obj)!=null) {
stringBuffer0.append(column.name());//列名
stringBuffer0.append("=");
Object col = aClass.getMethods()[i].invoke(obj);
if(col instanceof Date){
Date d = (Date) col;
stringBuffer0.append("to_date('");
stringBuffer0.append(DateUtils.getTimeStr(d));//填充值
stringBuffer0.append("', 'yyyy-mm-dd hh24:mi:ss')");
}else{
stringBuffer0.append("'");
stringBuffer0.append(col.toString());//填充值
stringBuffer0.append("'");
}
stringBuffer0.append(",");
} else if (joinColumn != null && aClass.getMethods()[i].invoke(obj)!=null) {
Object invoke = aClass.getMethods()[i].invoke(obj);
for (int j = 0; j < invoke.getClass().getMethods().length; j++) {
Id annotation3 = invoke.getClass().getMethods()[j].getAnnotation(Id.class);
if (annotation3 != null) {
stringBuffer0.append(joinColumn.name());//列名
stringBuffer0.append("='");
stringBuffer0.append(invoke.getClass().getMethods()[j].invoke(invoke).toString());//填充值
stringBuffer0.append("'");
stringBuffer0.append(",");
break;
}
}
} else if (id != null) {
name = aClass.getMethods()[i].getName();//"getId"
name = name.substring(3).toUpperCase();//去除"get",转换成大写
idValue=aClass.getMethods()[i].invoke(obj).toString();//填充值
}
}
stringBuffer0.deleteCharAt(stringBuffer0.length() - 1);
}catch (Exception e){
System.out.println(e.toString());
}
StringBuffer stringBuffer = new StringBuffer();
stringBuffer.append(" update ");
stringBuffer.append(table.name());
stringBuffer.append(" set ");
stringBuffer.append(stringBuffer0);
stringBuffer.append(" where ");
stringBuffer.append(name);
stringBuffer.append(" = '");
stringBuffer.append(idValue);
stringBuffer.append("'");
return stringBuffer.toString();
// System.out.println("SQL:"+stringBuffer.toString());
}
//单表删除使用；；生成对应的删除语句
@Override
public String createDelSQLString(List<String> list) {
// Class<?> aClass = clazz.getClass();
Table table = clazz.getAnnotation(Table.class);
StringBuffer stringBuffer0 = new StringBuffer();
String name ="";
try {
for (int i = 0; i < clazz.getMethods().length; i++) {
Id id = clazz.getMethods()[i].getAnnotation(Id.class);
if (id != null) {
name = clazz.getMethods()[i].getName();//"getId"
name = name.substring(3).toUpperCase();//去除"get",转换成大写
}
}
for (String id:list) {
stringBuffer0.append("'");
stringBuffer0.append(id);
stringBuffer0.append("'");
stringBuffer0.append(",");
}
stringBuffer0.deleteCharAt(stringBuffer0.length() - 1);
}catch (Exception e){
System.out.println(e.toString());
}
StringBuffer stringBuffer = new StringBuffer();
stringBuffer.append(" delete from ");
stringBuffer.append(table.name());
stringBuffer.append(" where ");
stringBuffer.append(name);//id
stringBuffer.append(" in ( ");
stringBuffer.append(stringBuffer0);
stringBuffer.append(" )");
return stringBuffer.toString();
// System.out.println("SQL:"+stringBuffer.toString());
}
}
创建dao层A表对应的接口和类：
public interface ADao extends BaseDao<ABean>{
}
@Repository("ADaoImpl")
public class ADaoImpl extends BaseDaoImpl<ABean> implements ADao {
}
创建dao层B表对应的接口和类：
public interface BDao extends BaseDao<BBean>{
}
@Repository("BDaoImpl")
public class BDaoImpl extends BaseDaoImpl<BBean> implements BDao {
}
最后在服务层调用即可生成对应的sql。
java
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