1. hibernate简介
1.1 什么是hibernate？
hibernate是一个持久层的ORM框架
ORM：Object Relational Mapping，对象关系映射
1.2 为什么使用hibernate？
可以自动生成sql语句，减少重复的工作，节省时间在更有意义的地方。
1.3 hibernate的优势
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1.4 下载地址
https://sourceforge.net/projects/hibernate/files/hibernate-orm/
2. 使用hibernate
使用idea不需要自己手动导入约束，使用idea不需要自己手动导入约束，使用idea不需要自己手动导入约束
目录结构
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- 书写主配置文件
<hibernate-configuration>
<session-factory>
<!-- 数据库驱动 -->
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<!-- 数据库url -->
<property name="hibernate.connection.url">jdbc:mysql://xxx.xxx.7.239/xiaobang</property>
<!-- 数据库连接用户名 -->
<property name="hibernate.connection.username">root</property>
<!-- 数据库连接密码 -->
<property name="hibernate.connection.password">123456789</property>
<!-- 数据库方言
不同的数据库中,sql语法略有区别. 指定方言可以让hibernate框架在生成sql语句时.针对数据库的方言生成.
sql99标准: DDL 定义语言 库表的增删改查
DCL 控制语言 事务 权限
DML 操纵语言 增删改查
注意: MYSQL在选择方言时,请选择最短的方言.
-->
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- #hibernate.show_sql true
#hibernate.format_sql true
-->
<!-- 将hibernate生成的sql语句打印到控制台 -->
<property name="hibernate.show_sql">true</property>
<!-- 将hibernate生成的sql语句格式化(语法缩进) -->
<property name="hibernate.format_sql">true</property>
<!--
## auto schema export 自动导出表结构. 自动建表
#hibernate.hbm2ddl.auto create 自动建表.每次框架运行都会创建新的表.以前表将会被覆盖,表数据会丢失.(开发环境中测试使用)
#hibernate.hbm2ddl.auto create-drop 自动建表.每次框架运行结束都会将所有表删除.(开发环境中测试使用)
#hibernate.hbm2ddl.auto update(推荐使用) 自动生成表.如果已经存在不会再生成.如果表有变动.自动更新表(不会删除任何数据).
#hibernate.hbm2ddl.auto validate 校验.不自动生成表.每次启动会校验数据库中表是否正确.校验失败.
-->
<property name="hbm2ddl.auto">update</property>
<!-- 引入orm元数据
路径书写: 填写src下的路径
-->
<mapping resource="domain/Customer.hbm.xml" />
</session-factory>
</hibernate-configuration>
- 创建Customer类
public class Customer {
/*
* CREATE TABLE `t_customer` (
`cust_id` BIGINT(32) NOT NULL AUTO_INCREMENT COMMENT '客户编号(主键)',
`cust_name` VARCHAR(32) NOT NULL COMMENT '客户名称(公司名称)',
`cust_source` VARCHAR(32) DEFAULT NULL COMMENT '客户信息来源',
`cust_industry` VARCHAR(32) DEFAULT NULL COMMENT '客户所属行业',
`cust_level` VARCHAR(32) DEFAULT NULL COMMENT '客户级别',
`cust_linkman` VARCHAR(64) DEFAULT NULL COMMENT '联系人',
`cust_phone` VARCHAR(64) DEFAULT NULL COMMENT '固定电话',
`cust_mobile` VARCHAR(16) DEFAULT NULL COMMENT '移动电话',
PRIMARY KEY (`cust_id`)
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
*/
private Long cust_id;
private String cust_name;
private String cust_source;
private String cust_industry;
private String cust_level;
private String cust_linkman;
private String cust_phone;
private String cust_mobile;
public Long getCust_id() {
return cust_id;
}
public void setCust_id(Long cust_id) {
this.cust_id = cust_id;
}
public String getCust_name() {
return cust_name;
}
public void setCust_name(String cust_name) {
this.cust_name = cust_name;
}
public String getCust_source() {
return cust_source;
}
public void setCust_source(String cust_source) {
this.cust_source = cust_source;
}
public String getCust_industry() {
return cust_industry;
}
public void setCust_industry(String cust_industry) {
this.cust_industry = cust_industry;
}
public String getCust_level() {
return cust_level;
}
public void setCust_level(String cust_level) {
this.cust_level = cust_level;
}
public String getCust_linkman() {
return cust_linkman;
}
public void setCust_linkman(String cust_linkman) {
this.cust_linkman = cust_linkman;
}
public String getCust_phone() {
return cust_phone;
}
public void setCust_phone(String cust_phone) {
this.cust_phone = cust_phone;
}
public String getCust_mobile() {
return cust_mobile;
}
public void setCust_mobile(String cust_mobile) {
this.cust_mobile = cust_mobile;
}
@Override
public String toString() {
return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]";
}
}
- 书写orm配置文件
<!-- 配置表与实体对象的关系 -->
<!-- package属性:填写一个包名.在元素内部凡是需要书写完整类名的属性,可以直接写简答类名了. -->
<hibernate-mapping package="domain" >
<!--
class元素: 配置实体与表的对应关系的
name: 完整类名
table:数据库表名
-->
<class name="Customer" table="cst_customer" >
<!-- id元素:配置主键映射的属性
name: 填写主键对应属性名
column(可选): 填写表中的主键列名.默认值:列名会默认使用属性名
type(可选):填写列(属性)的类型.hibernate会自动检测实体的属性类型.
每个类型有三种填法: java类型|hibernate类型|数据库类型
not-null(可选):配置该属性(列)是否不能为空. 默认值:false
length(可选):配置数据库中列的长度. 默认值:使用数据库类型的最大长度
-->
<id name="cust_id" >
<!-- generator:主键生成策略 -->
<generator class="native"></generator>
</id>
<!-- property元素:除id之外的普通属性映射
name: 填写属性名
column(可选): 填写列名
type(可选):填写列(属性)的类型.hibernate会自动检测实体的属性类型.
每个类型有三种填法: java类型|hibernate类型|数据库类型
not-null(可选):配置该属性(列)是否不能为空. 默认值:false
length(可选):配置数据库中列的长度. 默认值:使用数据库类型的最大长度
-->
<property name="cust_name" column="cust_name" >
<!-- <column name="cust_name" sql-type="varchar" ></column> -->
</property>
<property name="cust_source" column="cust_source" ></property>
<property name="cust_industry" column="cust_industry" ></property>
<property name="cust_level" column="cust_level" ></property>
<property name="cust_linkman" column="cust_linkman" ></property>
<property name="cust_phone" column="cust_phone" ></property>
<property name="cust_mobile" column="cust_mobile" ></property>
</class>
</hibernate-mapping>
- 测试
public class testHibernate {
@Test
//保存客户
public void fun1(){
Configuration conf = new Configuration().configure();
SessionFactory sessionFactory = conf.buildSessionFactory();
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
Customer c = new Customer();
c.setCust_id(1l);
c.setCust_name("lisi");
session.save(c);//执行保存
tx.commit();
session.close();
sessionFactory.close();
}
}
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3. API详解
public class testHibernate {
@Test
public void testFunc01(){
// 创建，调用空参构造，读取指定的主配置文件 -> 默认读取src下的"hibernate.cfg.xml"
Configuration conf = new Configuration().configure();
// 根据配置信息创建sessionFactory对象
// 注意： 1.sessionFactory 负责保存和使用所有配置信息，消耗内存资源非常大
// 2.sessionFactory 属于线程安全的对象设计
// 保证在一个web项目中，只有一个sessionFactory对象
SessionFactory sessionFactory = conf.buildSessionFactory();
// 打开一个新的session对象
Session session = sessionFactory.openSession();
// 开启事务并获得操作事务的Transaction对象
Transaction transaction = session.beginTransaction();
// 查询
Customer customer = session.get(Customer.class, 1l);
System.out.println(customer);
// 提交事务
transaction.commit();
// 释放资源
session.close();
// 释放资源
sessionFactory.close();
}
}
4. 抽取工具类
public class HibernateUtils {
private static SessionFactory sessionFactory;
/// 只能有一个sessionFactory
static {
Configuration conf = new Configuration().configure();
sessionFactory = conf.buildSessionFactory();
}
public static Session openSession() {
Session session = sessionFactory.openSession();
return session;
}
public static Session getCurrentSession() {
Session session = sessionFactory.getCurrentSession();
return session;
}
}
测试
@Test
public void testFunc02(){
Session session = HibernateUtils.openSession();
Transaction transaction = session.beginTransaction();
Customer customer = session.get(Customer.class, 1l);
customer.setCust_name("wangwu");
System.out.println(customer);
// 提交事务
transaction.commit();
// 释放资源
session.close();
}
5. 使用hibernate来构建完整的web项目
搭建一个网页，用来保存用户
1.目录结构
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2.导入网页资源（这里我们不关注网页的代码）
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3.完成保存用户的需求
dao层
public interface ServiceDao {
public void save(Customer customer);
}
public class CustomerDaoImpl implements CustomerDao {
@Override
public void save(Customer customer) {
Session session = HibernateUtils.openSession();
Transaction transaction = session.beginTransaction();
session.save(customer);
transaction.commit();
session.close();
}
}
service层
public interface CustomerService {
public void save(Customer customer);
}
public class CustomerServiceImpl implements CustomerService {
private CustomerDao serviceDao = new CustomerDaoImpl();
@Override
public void save(Customer customer) {
serviceDao.save(customer);
}
}
// web层
@WebServlet(name = "AddCustomerServlet")
public class AddCustomerServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
private CustomerService customerService = new CustomerServiceImpl();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 1. 获得参数，封装到customer对象
Customer customer = new Customer();
try {
BeanUtils.populate(customer, request.getParameterMap());
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
// 2.调用service保存客户
customerService.save(customer);
// 3.重定向到客户列表
response.sendRedirect(request.getContextPath() + "/ListCustomerServlet");
}
}
配置文件
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1">
<display-name>hibernate_crm</display-name>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
<!--使用filter解决乱码问题-->
<filter>
<filter-name>encodeFilter</filter-name>
<filter-class>web.filter.GenericEncodingFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>encodeFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<servlet>
<description></description>
<display-name>AddCustomerServlet</display-name>
<servlet-name>AddCustomerServlet</servlet-name>
<servlet-class>web.AddCustomerServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>AddCustomerServlet</servlet-name>
<url-pattern>/AddCustomerServlet</url-pattern>
</servlet-mapping>
</web-app>
6. 使用filter解决乱码
前面给出了filter的配置，这里直接给出filter的代码
/**
* 通用编码解决方案
*
*/
public class GenericEncodingFilter implements Filter {
public void destroy() {
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
// 转型为与协议相关对象
HttpServletRequest httpServletRequest = (HttpServletRequest) request;
// 对request包装增强
HttpServletRequest myRequest = new MyRequest(httpServletRequest);
chain.doFilter(myRequest, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
}
}
// 自定义request对象
class MyRequest extends HttpServletRequestWrapper {
private HttpServletRequest request;
private boolean hasEncode;
public MyRequest(HttpServletRequest request) {
super(request);// super必须写
this.request = request;
}
// 对需要增强方法 进行覆盖
@Override
public Map getParameterMap() {
// 先获得请求方式
String method = request.getMethod();
if (method.equalsIgnoreCase("post")) {
// post请求
try {
// 处理post乱码
request.setCharacterEncoding("utf-8");
return request.getParameterMap();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
} else if (method.equalsIgnoreCase("get")) {
// get请求
Map<String, String[]> parameterMap = request.getParameterMap();
if (!hasEncode) { // 确保get手动编码逻辑只运行一次
for (String parameterName : parameterMap.keySet()) {
String[] values = parameterMap.get(parameterName);
if (values != null) {
for (int i = 0; i < values.length; i++) {
try {
// 处理get乱码
values[i] = new String(values[i].getBytes("ISO-8859-1"), "utf-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
}
}
hasEncode = true;
}
return parameterMap;
}
return super.getParameterMap();
}
@Override
public String getParameter(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
if (values == null) {
return null;
}
return values[0]; // 取回参数的第一个值
}
@Override
public String[] getParameterValues(String name) {
Map<String, String[]> parameterMap = getParameterMap();
String[] values = parameterMap.get(name);
return values;
}
}
