Spring JDBCTemplate学习

最近学习Spring框架，写这篇文章是对这段时间学习的一个总结也是学习的笔记，这篇笔记主要讲Spring 提供的一个简易持久层操作数据的模板JDBCTemplate的增删改查功能，他跟自己用DBUtils封装的持久层有点类似。

在文章开始前，我们先来看下Spring为几种持久化技术提供的简单操作模板类。

ORM持久化技术	Spring提供的模板类
JDBC	org.springframework.jdbc.core.JdbcTemplate
Hibernate5.0	org.springframework.orm.hibernate5.HibernateTemplate
MyBatis	org.springframework.orm.ibatis.SqlMapClientTemplate 后面已经被Spring移除
JPA	org.springfrmaework.orm.jpa.JpaTemplate

1. 依赖架包导入

Spring 核心包

commons-logging-1.1.3.jar
spring-beans-4.0.6.RELEASE.jar
spring-context-4.0.6.RELEASE.jar
spring-core-4.0.6.RELEASE.jar
spring-expression-4.0.6.RELEASE.jar

JDBC支持包

spring-jdbc-4.0.6.RELEASE.jar
spring-tx-4.0.6.RELEASE.jar

数据库驱动包和连接池架包

mysql-connector-java-5.1.7-bin.jar
c3p0-0.9.1.2.jar

2. 简单操作示例

先简单来，不c3p0连接池，而是用Spring配置内置的连接池DriverManagerDataSource做一个JDBCTemplate的数据库操作，来看看JDBCTemplate的初步用法(前提自己创建好数据库并定义好表)。

/**
 * JDBCTemplate简单操作测试类
 * @author liuchao
 */
public class JDBCDataSourceTest {

    private DriverManagerDataSource dataSource;

    @Before
    public void beforeAction() {
        dataSource = new DriverManagerDataSource();
        dataSource.setDriverClassName("com.mysql.jdbc.Driver");
        dataSource.setUrl("jdbc:mysql://10.22.70.2:3306/database_chao?useUnicode=true&characterEncoding=utf8");
        dataSource.setUsername("xxx");
        dataSource.setPassword("xxx");
    }

    //增
    public void testSimpleInsert() {..

    //删
    public void testSimpleDelete() {..

    //改
    public void testSimpleUpdate() {..

    //聚合查询
    public void testSimpleAggregation() {..

    //查: 执行给定静态SQL的查询，使用RowCallbackHandler以每行为基础读取ResultSet。
    public void testSimpleQuery_RowCallbackHandler() {..
    
    //查: 执行给定静态SQL的查询，通过RowMapper将每一行映射到Java对象。
    public void testSimpleQuery_RowMapper() {..
    
    //查: 在给定静态SQL的情况下执行查询，使用ResultSetExtractor读取ResultSet。
    @Test
    public void testSimpleQuery_ResultSetExtractor() {..

插入 删除 更新 都用 update.. 方法, 其中用 public int update(String sql, Object... args) 方法最为方便。
查询用 query..。

• ① 插入

@Test
public void testSimpleInsert() {

    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "insert into contact (name, age) values (?, ?)";
    int rows = template.update(sql, "测试", 12);
    System.out.println("执行影响行数 " + rows);
}

• ② 删除

@Test
public void testSimpleDelete() {

    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "delete from contact where id<?";
    int rows = template.update(sql, 18);
    System.out.println("执行影响行数 " + rows);
}

• ③ 更新

@Test
public void testSimpleUpdate() {

    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "update contact set name=?, age=? where id=?";
    int rows = template.update(sql, "测试更新", 24, 20);
    System.out.println("执行影响行数 " + rows);
}

• ④ 聚合查询 public <T> T queryForObject(String sql, Class<T> requiredType)

@Test 
public void testSimpleAggregation() {

    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "select count(id) from contact";
    long count = template.queryForObject(sql, Long.class);
    System.out.println("一共有 " + count + " 条记录");
}

• ⑤ 查询：执行给定静态SQL的查询，使用RowCallbackHandler以每行为基础读取ResultSet，以下面两种方法查询最为方便。
  public void query(String sql, RowCallbackHandler rch)
public void query(String sql, RowCallbackHandler rch, Object... args)

@Test
public void testSimpleQuery_RowCallbackHandler() {

    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "select * from contact";
    
    ArrayList<Contact> list = new ArrayList<Contact>();
    
    template.query(sql, new RowCallbackHandler() {
        
        @Override
        public void processRow(ResultSet rs) throws SQLException {
            Contact contact = new Contact();
            contact.setId(rs.getInt("id"));
            contact.setName(rs.getString("name"));
            contact.setAge(rs.getInt("age"));
            list.add(contact);
        }
    });
    
    for (Contact contact : list) { System.out.println(contact.toString()); }
}

• ⑥ 查询：执行给定静态SQL的查询，通过RowMapper将每一行映射到Java对象。以下面两种方法查询最为方便。

public <T> List<T> query(String sql, RowMapper<T> rowMapper)
public <T> List<T> query(String sql, RowMapper<T> rowMapper, Object... args)

@Test
public void testSimpleQuery_RowMapper() {
    
    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "select * from contact";
    
    List<Contact> list = template.query(sql, new RowMapper<Contact>() {

        @Override
        public Contact mapRow(ResultSet rs, int rowNum) throws SQLException {
            Contact contact = new Contact();
            contact.setId(rs.getInt("id"));
            contact.setName(rs.getString("name"));
            contact.setAge(rs.getInt("age"));
            return contact;
        }
    });
    
    for (Contact contact : list) { System.out.println(contact.toString()); }
}

• ⑦ 查询：在给定静态SQL的情况下执行查询，使用ResultSetExtractor读取ResultSet。以下面两种方法查询最为方便。

public <T> T query(final String sql, final ResultSetExtractor<T> rse)
public <T> T query(String sql, ResultSetExtractor<T> rse, Object... args)

@Test
public void testSimpleQuery_ResultSetExtractor() {

    JdbcTemplate template = new JdbcTemplate(dataSource);

    String sql = "select * from contact";

    List<Contact> list = template.query(sql, new ResultSetExtractor<List<Contact>>() {

        @Override
        public List<Contact> extractData(ResultSet rs) throws SQLException, DataAccessException {
            
            ArrayList<Contact> tempList = new ArrayList<Contact>();
            while (rs.next()) {
                Contact contact = new Contact();
                contact.setId(rs.getInt("id"));
                contact.setName(rs.getString("name"));
                contact.setAge(rs.getInt("age"));
                tempList.add(contact);
            }
            return tempList;
        }
    });
    
    for (Contact contact : list) { System.out.println(contact.toString()); }
}

由上面的小测试我们基本了解到该如何下手，接下来进行正式的操作，连接池配置到Spring的XML文件中，对象都用ioc set方式注入。

3. JDBCTemplate规范操作和配置

首先来看下Spring XML 文件的配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx" 
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd 
        http://www.springframework.org/schema/aop 
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd">
        
        
        <!-- 1. 连接池配置 -->
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            <property name="driverClass" value="com.mysql.jdbc.Driver"></property>
            <property name="jdbcUrl">
                <value><![CDATA[jdbc:mysql://10.22.70.2:3306/database_chao?useUnicode=true&characterEncoding=utf8]]></value>
            </property>
            <property name="user" value="xxx"></property>
            <property name="password" value="xxx"></property>
            <property name="initialPoolSize" value="1"></property>
            <property name="minPoolSize" value="1"></property>
            <property name="maxPoolSize" value="2"></property>
        </bean>
        
        
        <!-- 2. JDBCTemplate -->
        <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"></property>
        </bean
        
        
        <!-- 3. 项目里面自己创建类的bean定义部分 -->
        <bean id="contactDaoImpl" class="com.g_JdbcTemplate.dao.impl.ContactDaoImpl">
            <property name="template" ref="jdbcTemplate"></property>
        </bean>
        
        <bean id="contactService" class="com.g_JdbcTemplate.service.ContactService">
            <property name="contactDao" ref="contactDaoImpl"></property>
        </bean>
        
</beans>

接口省略，直接上实现类里面的增删改查代码

public class ContactDaoImpl implements ContactDao {
    
    private JdbcTemplate template;
    public void setTemplate(JdbcTemplate template) {
        this.template = template;
    }
    
    //增
    @Override
    public int insertContact(Contact contact) throws Exception {
        String sql = "insert into contact (name, age) values (?, ?)";
        int rows = template.update(sql, contact.getName(), contact.getAge());
        return rows;
    }

    //删
    @Override
    public int deleteContactById(int id) throws Exception {
        String sql = "delete from contact where id=?";
        int rows = template.update(sql, id);
        return rows;
    }

    //改
    @Override
    public int updateContact(Contact contact) throws Exception {
        String sql = "update contact set name=?, age=? where id=?";
        int rows = template.update(sql, contact.getName(), contact.getAge(), contact.getId());
        return rows;
    }

    //根据id查询
    @Override
    public Contact queryContactById(int id) throws Exception {
        
        String sql = "select * from contact where id=?";
        
        List<Contact> list = template.query(sql, new RowMapper<Contact>() {

            @Override
            public Contact mapRow(ResultSet rs, int rowNum) throws SQLException {
                Contact contact = new Contact();
                contact.setId(rs.getInt("id"));
                contact.setName(rs.getString("name"));
                contact.setAge(rs.getInt("age"));
                return contact;
            }
        }, id);
        
        return (list != null && list.size() > 0) ? list.get(0) : null;      
    }
    
    //查询全部
    @Override
    public List<Contact> queryAllContact() throws Exception {
        
        String sql = "select * from contact";
        
        List<Contact> list = template.query(sql, new RowMapper<Contact>() {

            @Override
            public Contact mapRow(ResultSet rs, int rowNum) throws SQLException {
                Contact contact = new Contact();
                contact.setId(rs.getInt("id"));
                contact.setName(rs.getString("name"));
                contact.setAge(rs.getInt("age"));
                return contact;
            }
        });
        
        return list;
    }
}

业务层代码，持久层出现异常接着往上抛，后面涉及到事务管理，异常回滚要用到。

public class ContactService {
    
    private ContactDao contactDao;
    public void setContactDao(ContactDao contactDao) {
        this.contactDao = contactDao;
    }
    
    public int insertContact(Contact contact) throws Exception {
        if (contact == null) { return 0; }
        return contactDao.insertContact(contact);
    }

    public int deleteContactById(int id) throws Exception {
        return contactDao.deleteContactById(id);
    }

    public int updateContact(Contact contact) throws Exception {
        if (contact == null) { return 0; }
        return contactDao.updateContact(contact);
    }

    public Contact queryContactById(int id) throws Exception {
        return contactDao.queryContactById(id);
    }

    public List<Contact> queryAllContact() throws Exception {
        return contactDao.queryAllContact();
    }
}

测试类

/**
 * 测试类
 * @author liuchao
 */
public class ContactTest {
    
    private ClassPathXmlApplicationContext context;
    
    @Before
    public void beforeAction() {
        context = new ClassPathXmlApplicationContext("com/g_JdbcTemplate/bean.xml");
    }
    
    @Test
    public void testInsertContact() {
        
        ContactService service = (ContactService) context.getBean("contactService");
        
        Contact contact = new Contact();
        contact.setName("Test");
        contact.setAge(13);
        
        int rows = 0;
        try {
            rows = service.insertContact(contact);
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        System.out.println("插入影响行数 " + rows);
    }

    @Test
    public void testDeleteContactById() {..

    @Test
    public void testUpdateContact() {..

    @Test
    public void testQueryContactById() {..

    @Test
    public void testQueryAllContact() {..

4. JDBCTemplate事务管理配置

请参考 Spring中持久层事务配置