JPA注解：根据实体生成数据表和字段的注释（正向工程）
1.JPA常见注解
请移步：http://blog.csdn.net/fly910905/article/details/78140411
2.JPA注解：表注释
@org.hibernate.annotations.Table(appliesTo = "TableName",comment="表注释")
/* * Hibernate, Relational Persistence for Idiomatic Java * * License: GNU Lesser General Public License (LGPL), version 2.1 or later. * See the lgpl.txt file in the root directory or . */package org.hibernate.annotations;import java.lang.annotation.Retention;import java.lang.annotation.Target;import static java.lang.annotation.ElementType.TYPE;import static java.lang.annotation.RetentionPolicy.RUNTIME;/** * Complementary information to a table either primary or secondary. * * @author Emmanuel Bernard */@Target({TYPE})@Retention(RUNTIME)public @interface Table { /** * name of the targeted table. */ String appliesTo(); /** * Indexes. */ Index[] indexes() default {}; /** * define a table comment. */ String comment() default ""; /** * Defines the Foreign Key name of a secondary table pointing back to the primary table. */ ForeignKey foreignKey() default @ForeignKey( name="" ); /** * If set to JOIN, the default, Hibernate will use an inner join to retrieve a * secondary table defined by a class or its superclasses and an outer join for a * secondary table defined by a subclass. * If set to select then Hibernate will use a * sequential select for a secondary table defined on a subclass, which will be issued only if a row * turns out to represent an instance of the subclass. Inner joins will still be used to retrieve a * secondary defined by the class and its superclasses. * * Only applies to secondary tables */ FetchMode fetch() default FetchMode.JOIN; /** * If true, Hibernate will not try to insert or update the properties defined by this join. * * Only applies to secondary tables */ boolean inverse() default false; /** * If enabled, Hibernate will insert a row only if the properties defined by this join are non-null * and will always use an outer join to retrieve the properties. * * Only applies to secondary tables */ boolean optional() default true; /** * Defines a custom SQL insert statement. * * Only applies to secondary tables */ SQLInsert sqlInsert() default @SQLInsert(sql=""); /** * Defines a custom SQL update statement. * * Only applies to secondary tables */ SQLUpdate sqlUpdate() default @SQLUpdate(sql=""); /** * Defines a custom SQL delete statement. * * Only applies to secondary tables */ SQLDelete sqlDelete() default @SQLDelete(sql="");}
3.JPA注解：字段注释
@Column(name="columnComment",columnDefinition="varchar(200) COMMENT '字段注释'")
/* * Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved. * * This program and the accompanying materials are made available under the * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 * which accompanies this distribution. The Eclipse Public License is available * at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License * is available at http://www.eclipse.org/org/documents/edl-v10.php. */package javax.persistence;import java.lang.annotation.Retention;import java.lang.annotation.Target;import static java.lang.annotation.ElementType.FIELD;import static java.lang.annotation.ElementType.METHOD;import static java.lang.annotation.RetentionPolicy.RUNTIME;/** * Is used to specify the mapped column for a persistent property or field. * If no Column annotation is specified, the default values apply. * *
* Example 1: * * @Column(name="DESC", nullable=false, length=512) * public String getDescription() { return description; } * * Example 2: * * @Column(name="DESC", * columnDefinition="CLOB NOT NULL", * table="EMP_DETAIL") * @Lob * public String getDescription() { return description; } * * Example 3: * * @Column(name="ORDER_COST", updatable=false, precision=12, scale=2) * public BigDecimal getCost() { return cost; } * *
* * * @since Java Persistence 1.0 */@Target({METHOD, FIELD})@Retention(RUNTIME)public @interface Column { /** * (Optional) The name of the column. Defaults to * the property or field name. */ String name() default ""; /** * (Optional) Whether the column is a unique key. This is a * shortcut for the UniqueConstraint annotation at the table * level and is useful for when the unique key constraint * corresponds to only a single column. This constraint applies * in addition to any constraint entailed by primary key mapping and * to constraints specified at the table level. */ boolean unique() default false; /** * (Optional) Whether the database column is nullable. */ boolean nullable() default true; /** * (Optional) Whether the column is included in SQL INSERT * statements generated by the persistence provider. */ boolean insertable() default true; /** * (Optional) Whether the column is included in SQL UPDATE * statements generated by the persistence provider. */ boolean updatable() default true; /** * (Optional) The SQL fragment that is used when * generating the DDL for the column. * Defaults to the generated SQL to create a
* column of the inferred type. */ String columnDefinition() default ""; /** * (Optional) The name of the table that contains the column. * If absent the column is assumed to be in the primary table. */ String table() default ""; /** * (Optional) The column length. (Applies only if a * string-valued column is used.) */ int length() default 255; /** * (Optional) The precision for a decimal (exact numeric) * column. (Applies only if a decimal column is used.) * Value must be set by developer if used when generating * the DDL for the column. */ int precision() default 0; /** * (Optional) The scale for a decimal (exact numeric) column. * (Applies only if a decimal column is used.) */ int scale() default 0;}
4.示例：
4.1实体（实体中使用了Swagger，不需要的可去掉）：
package com.newcapec.dao.domain;import io.swagger.annotations.ApiModel;import io.swagger.annotations.ApiModelProperty;import javax.persistence.Column;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;import java.util.Date;import static javax.persistence.GenerationType.AUTO;/** * @Title: 用户报名缴费信息实体 * @ClassName: com.newcapec.dao.domain.UserEnrollPay.java * @Description: 位于校内的报名系统--中间库上 * * @Copyright 2016-2017 新开普 - Powered By 研发中心 * @author: 王延飞 * @date: 2017-12-13 15:31 * @version V1.0 */@Entity@org.hibernate.annotations.Table(appliesTo = "user_enroll_pay",comment="用户报名缴费信息")@ApiModel("Person(用户报名缴费信息)")public class UserEnrollPay { @Id @GeneratedValue(strategy = AUTO) @Column(name = "id", unique = true, nullable = false,columnDefinition="bigint(20) COMMENT '主键id'") @ApiModelProperty("主键id") private Long id; /** * 证件号 */ @Column(columnDefinition="varchar(20) COMMENT '证件号'") @ApiModelProperty("证件号") private String idserial; /** * 订单金额 */ @Column(columnDefinition = "Decimal(10,2) COMMENT '订单金额'", scale = 2 ,precision=10) @ApiModelProperty("订单金额") private double orderamt; /** * 支付时间 */ @Column(columnDefinition="datetime COMMENT '支付时间'") @ApiModelProperty("支付时间") private Date paytime; /** * 支付标志 * 0-未支付 * 1-支付中 * 2-支付成功 * 3-支付失败 * 4-已过期 * 5-已取消 */ @Column(columnDefinition="int(2) COMMENT '支付标志 0-未支付 1-支付中 2-支付成功 3-支付失败 4-已过期 5-已取消'") @ApiModelProperty("支付标志 0-未支付 1-支付中 2-支付成功 3-支付失败 4-已过期 5-已取消") private Integer payflag; public Long getId() { return id; } public void setId(Long id) { this.id = id; } public String getIdserial() { return idserial; } public void setIdserial(String idserial) { this.idserial = idserial; } public double getOrderamt() { return orderamt; } public void setOrderamt(double orderamt) { this.orderamt = orderamt; } public Date getPaytime() { return paytime; } public void setPaytime(Date paytime) { this.paytime = paytime; } public Integer getPayflag() { return payflag; } public void setPayflag(Integer payflag) { this.payflag = payflag; } @Override public String toString() { return "UserEnrollPay{" + "id=" + id + ", idserial='" + idserial + '\'' + ", orderamt=" + orderamt + ", paytime=" + paytime + ", payflag=" + payflag + '}'; }}
4.2生成的数据表
CREATE TABLE `user_enroll_pay` ( `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键id', `idserial` varchar(20) COLLATE utf8_unicode_ci DEFAULT NULL COMMENT '证件号', `orderamt` decimal(10,2) DEFAULT NULL COMMENT '订单金额', `payflag` int(2) DEFAULT NULL COMMENT '支付标志 0-未支付 1-支付中 2-支付成功 3-支付失败 4-已过期 5-已取消', `paytime` datetime DEFAULT NULL COMMENT '支付时间', PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci COMMENT='用户报名缴费信息';