160727、自定义hibernate主键生成策略生成字符串+数字自增长

需求：需要自增长注解如MyId0001、MyId0002、MyId0003

实现：实现这个接口org.hibernate.id.IdentifierGenerator

一、MyIdGenerator.java(测试用，实际项目中获取链接等可以改变)
import java.io.Serializable;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import org.apache.commons.lang.StringUtils;
import org.hibernate.HibernateException;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.IdentifierGenerator;
public class MyIdGenerator implements IdentifierGenerator{
    @Override
    public Serializable generate(SessionImplementor session, Object object)
            throws HibernateException {
        String prefix = "MyId";
        Connection connection = session.connection();
        try {
            PreparedStatement ps = connection
                    .prepareStatement("SELECT nextval ('seq_id') as nextval");
            ResultSet rs = ps.executeQuery();
            if (rs.next()) {
                int id = rs.getInt("nextval");
                String code = prefix + StringUtils.leftPad("" + id,3, '0');
                log.debug("Generated Stock Code: " + code);
                return code;
            }
        } catch (SQLException e) {
            log.error(null, e);
            throw new HibernateException(
                    "Unable to generate Stock Code Sequence");
        }
        return null;
    }
}

二、配置hibernate主键生成策略

基于配置文件的hibernate（TestHibernateIdentifier.xml）

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.fire.front.entity">
    <class name="TestHibernateIdentifier" table="test_hibernate_identifier"  dynamic-update="true">
        <meta attribute="sync-DAO">false</meta>
        <cache usage="read-write"/>
        <id name="id" type="string" column="id">
                <generator class="com.gwold.common.util.MyIdGenerator"/>
        </id>    
        <property name="name" type="string" column="name" length="40"/>       
    </class>
</hibernate-mapping>

基于注解的方式
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import org.hibernate.annotations.GenericGenerator;
public class TestHibernateIdentifier implements Serializable{
    @Id
    @GenericGenerator(name="seq_id", strategy="com.gwold.common.util.MyIdGenerator")
    @GeneratedValue(generator="seq_id")
    @Column(name = "id", unique = true, nullable = false, length = 20)
    private String id;
    private String name;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
}