1.JPA常见注解

1. 请移步：http://blog.csdn.net/fly910905/article/details/78140411

2.JPA注解：表注释

1. @org.hibernate.annotations.Table(appliesTo = "TableName",comment="表注释")
2. /*
3. * Hibernate, Relational Persistence for Idiomatic Java
4. *
5. * License: GNU Lesser General Public License(LGPL), version 2.1 or later.
6. * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
7. */
8. package org.hibernate.annotations;
10. import java.lang.annotation.Retention;
11. import java.lang.annotation.Target;
13. importstatic java.lang.annotation.ElementType.TYPE;
14. importstatic java.lang.annotation.RetentionPolicy.RUNTIME;
16. /**
17. * Complementary information to a table either primary or secondary.
18. *
19. * @author Emmanuel Bernard
20. */
21. @Target({TYPE})
22. @Retention(RUNTIME)
23. public@interface Table {
24. /**
25. * name of the targeted table.
26. */
27. String appliesTo();
29. /**
30. * Indexes.
31. */
32. Index[] indexes() default {};
34. /**
35. * define a table comment.
36. */
37. String comment()default"";
39. /**
40. * Defines the Foreign Key name of a secondary table pointing back to the primary table.
41. */
42. ForeignKey foreignKey()default@ForeignKey( name="" );
44. /**
45. * If set to JOIN, the default, Hibernate will use an inner join to retrieve a
46. * secondary table defined by a classor its superclasses and an outer join for a
47. * secondary table defined by a subclass.
48. * If set to select then Hibernate will use a
49. * sequential select for a secondary table defined on a subclass, which will be issued only if a row
50. * turns out to represent an instance of the subclass. Inner joins will still be used to retrieve a
51. * secondary defined by the classand its superclasses.
52. *
53. * <b>Only applies to secondary tables</b>
54. */
55. FetchMode fetch()default FetchMode.JOIN;
57. /**
58. * If true, Hibernate will not try to insert or update the properties defined by this join.
59. *
60. * <b>Only applies to secondary tables</b>
61. */
62. booleaninverse()defaultfalse;
64. /**
65. * If enabled, Hibernate will insert a row only if the properties defined by this join are non-null
66. * and will always use an outer join to retrieve the properties.
67. *
68. * <b>Only applies to secondary tables</b>
69. */
70. booleanoptional()defaulttrue;
72. /**
73. * Defines a custom SQL insert statement.
74. *
75. * <b>Only applies to secondary tables</b>
76. */
77. SQLInsert sqlInsert()default@SQLInsert(sql="");
79. /**
80. * Defines a custom SQL update statement.
81. *
82. * <b>Only applies to secondary tables</b>
83. */
84. SQLUpdate sqlUpdate()default@SQLUpdate(sql="");
86. /**
87. * Defines a custom SQL delete statement.
88. *
89. * <b>Only applies to secondary tables</b>
90. */
91. SQLDelete sqlDelete()default@SQLDelete(sql="");
92. }

3.JPA注解：字段注释

1. @Column(name="columnComment",columnDefinition="varchar(200) COMMENT '字段注释'")  
2. /*
3. * Copyright (c) 2008, 2009, 2011 Oracle, Inc. All rights reserved.
4. *
5. * This program and the accompanying materials are made available under the
6. * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
7. * which accompanies this distribution.  The Eclipse Public License is available
8. * at http://www.eclipse.org/legal/epl-v10.html and the Eclipse Distribution License
9. * is available at http://www.eclipse.org/org/documents/edl-v10.php.
10. */
11. package javax.persistence;
13. import java.lang.annotation.Retention;
14. import java.lang.annotation.Target;
16. importstatic java.lang.annotation.ElementType.FIELD;
17. importstatic java.lang.annotation.ElementType.METHOD;
18. importstatic java.lang.annotation.RetentionPolicy.RUNTIME;
20. /**
21. * Is used to specify the mapped column for a persistent property or field.
22. * If no <code>Column</code> annotation is specified, the default values apply.
23. *
24. * <blockquote><pre>
25. *    Example 1:
26. *
27. *    @Column(name="DESC", nullable=false, length=512)
28. *    public String getDescription() { return description; }
29. *
30. *    Example 2:
31. *
32. *    @Column(name="DESC",
33. *            columnDefinition="CLOB NOT NULL",
34. *            table="EMP_DETAIL")
35. *    @Lob
36. *    public String getDescription() { return description; }
37. *
38. *    Example 3:
39. *
40. *    @Column(name="ORDER_COST", updatable=false, precision=12, scale=2)
41. *    public BigDecimal getCost() { return cost; }
42. *
43. * </pre></blockquote>
44. *
45. *
46. * @since Java Persistence 1.0
47. */
48. @Target({METHOD, FIELD})
49. @Retention(RUNTIME)
50. public@interface Column {
52.    /**
53.     * (Optional) The name of the column. Defaults to
54. * the property or field name.
55.     */
56.    String name()default"";
58.    /**
59.     * (Optional) Whether the column is a unique key.  This is a
60.     * shortcut for the <code>UniqueConstraint</code> annotation at the table
61.     * level and is useful for when the unique key constraint
62.     * corresponds to only a single column. This constraint applies
63.     * in addition to any constraint entailed by primary key mapping and
64.     * to constraints specified at the table level.
65.     */
66.    booleanunique()defaultfalse;
68.    /**
69.     * (Optional) Whether the database column is nullable.
70.     */
71.    booleannullable()defaulttrue;
73.    /**
74.     * (Optional) Whether the column is included in SQL INSERT
75.     * statements generated by the persistence provider.
76.     */
77.    booleaninsertable()defaulttrue;
79.    /**
80.     * (Optional) Whether the column is included in SQL UPDATE
81.     * statements generated by the persistence provider.
82.     */
83.    booleanupdatable()defaulttrue;
85.    /**
86.     * (Optional) The SQL fragment that is used when
87.     * generating the DDL for the column.
88.     * <p> Defaults to the generated SQL to create a
89.     * column of the inferred type.
90.     */
91.    String columnDefinition()default"";
93.    /**
94.     * (Optional) The name of the table that contains the column.
95. * If absent the column is assumed to be in the primary table.
96.     */
97.    String table()default"";
99.    /**
100.     * (Optional) The column length. (Applies only if a
101.     * string-valued column is used.)
102.     */
103.    intlength()default255;
105.    /**
106.     * (Optional) The precision for a decimal(exact numeric)
107. * column. (Applies only if a decimal column is used.)
108.     * Value must be set by developer if used when generating
109.     * the DDL for the column.
110.     */
111.    intprecision()default0;
113.    /**
114.     * (Optional) The scale for a decimal(exact numeric) column.
115.     * (Applies only if a decimal column is used.)
116.     */
117.    intscale()default0;
118. }

4.示例：

4.1实体（实体中使用了Swagger，不需要的可去掉）：

1. package com.newcapec.dao.domain;
3. import io.swagger.annotations.ApiModel;
4. import io.swagger.annotations.ApiModelProperty;
6. import javax.persistence.Column;
7. import javax.persistence.Entity;
8. import javax.persistence.GeneratedValue;
9. import javax.persistence.Id;
10. import java.util.Date;
12. importstatic javax.persistence.GenerationType.AUTO;
16. /**
17. * @Title: 用户报名缴费信息实体
18. * @ClassName: com.newcapec.dao.domain.UserEnrollPay.java
19. * @Description: 位于校内的报名系统--中间库上
20. *
21. * @Copyright2016-2017 新开普 - Powered By 研发中心
22. * @author: 王延飞
23. * @date:  2017-12-1315:31
24. * @version V1.0
25. */
26. @Entity
27. @org.hibernate.annotations.Table(appliesTo = "user_enroll_pay",comment="用户报名缴费信息")
28. @ApiModel("Person(用户报名缴费信息)")
29. publicclassUserEnrollPay {
31.    @Id
32.    @GeneratedValue(strategy = AUTO)
33.    @Column(name = "id", unique = true, nullable = false,columnDefinition="bigint(20) COMMENT '主键id'")
34.    @ApiModelProperty("主键id")
35.    private Long id;
37.    /**
38.     * 证件号
39.     */
40.    @Column(columnDefinition="varchar(20) COMMENT '证件号'")
41.    @ApiModelProperty("证件号")
42.    private String idserial;
44.    /**
45.     * 订单金额
46.     */
47.    @Column(columnDefinition = "Decimal(10,2) COMMENT '订单金额'", scale = 2 ,precision=10)
48.    @ApiModelProperty("订单金额")
49.    privatedouble orderamt;
51.    /**
52.     * 支付时间
53.     */
54.    @Column(columnDefinition="datetime COMMENT '支付时间'")
55.    @ApiModelProperty("支付时间")
56.    private Date paytime;
57.    /**
58.     * 支付标志
59.     * 0-未支付
60.     * 1-支付中
61.     * 2-支付成功
62.     * 3-支付失败
63.     * 4-已过期
64.     * 5-已取消
65.     */
66.    @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'")
67.    @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")
68.    private Integer payflag;
71.    public Long getId() {
72.        return id;
73.    }
75.    publicvoidsetId(Long id) {
76.        this.id = id;
77.    }
79.    public String getIdserial() {
80.        return idserial;
81.    }
83.    publicvoidsetIdserial(String idserial) {
84.        this.idserial = idserial;
85.    }
87.    publicdoublegetOrderamt() {
88.        return orderamt;
89.    }
91.    publicvoidsetOrderamt(double orderamt) {
92.        this.orderamt = orderamt;
93.    }
95.    public Date getPaytime() {
96.        return paytime;
97.    }
99.    publicvoidsetPaytime(Date paytime) {
100.        this.paytime = paytime;
101.    }
103.    public Integer getPayflag() {
104.        return payflag;
105.    }
107.    publicvoidsetPayflag(Integer payflag) {
108.        this.payflag = payflag;
109.    }
111.    @Override
112.    public String toString() {
113.        return"UserEnrollPay{" +
114.                "id=" + id +
115.                ", idserial='" + idserial + '\'' +
116.                ", orderamt=" + orderamt +
117.                ", paytime=" + paytime +
118.                ", payflag=" + payflag +
119.                '}';
120.    }
121. }

4.2生成的数据表

1. CREATETABLE `user_enroll_pay` (
2.  `id` bigint(20) NOTNULL AUTO_INCREMENT COMMENT '主键id',
3.  `idserial` varchar(20) COLLATE utf8_unicode_ci DEFAULTNULL COMMENT '证件号',
4.  `orderamt` decimal(10,2) DEFAULTNULL COMMENT '订单金额',
5.  `payflag` int(2) DEFAULTNULL 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',
6.  `paytime` datetime DEFAULTNULL COMMENT '支付时间',
7.  PRIMARY KEY (`id`)
8. ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci COMMENT='用户报名缴费信息';