Spring使用jdbcTemplate

JdbcTemplate简介

1. 为了使JDBC更加易于使用，Spring在JDBC API上定义了一个抽象层，以此建立一个JDBC存取框架
2. 作为Spring JDBC框架的核心，JDBC模板的设计目的是为不同类型的JDBC操作提供模板方法，每个模板方法都能控制整个过程，并允许覆盖过程中的特定任务。通过这种方式，可以在尽可能保留灵活性的情况下，将数据库存取的工作量降到最低。

代码示例：

首先是数据库的配置。数据库中包含employee和department两张表。

1.jdbc.properties文件

jdbc.user=scott
jdbc.password=tiger
jdbc.driverClass=oracle.jdbc.driver.OracleDriver
jdbc.jdbcUrl=jdbc:oracle:thin:@localhost:1521:orcl

jdbc.initialPoolSize=5
jdbc.maxPoolSize=10

 

2. spring的配置文件

  <?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: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-4.1.xsd">
       <context:component-scan base-package="com.yl.spring.jdbc"></context:component-scan>
 
      <!-- 导入属性文件 -->
      <context:property-placeholder location="classpath:db.properties"/>
      <!-- 配置c3p0数据源 -->
      <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
         <property name="user" value="${jdbc.user}"></property>
         <property name="password" value="${jdbc.password}"></property>
         <property name="driverClass" value="${jdbc.driverClass}"></property>
         <property name="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
         
         <property name="initialPoolSize" value="${jdbc.initialPoolSize}"></property>
        <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
      </bean>
 
       <!-- 配置Spring的JdbcTemplate -->
      <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
          <property name="dataSource" ref="dataSource"></property>
      </bean>
 </beans>

 package com.yl.spring.jdbc;
 
 public class Employee {
     private Integer id;
     private String lastName;
     private String email;
     
     private Department department;
  
     public Integer getId() {
         return id;
     }
 
    public void setId(Integer id) {
         this.id = id;
     }
 
     public String getLastName() {
         return lastName;
     }
 
     public void setLastName(String lastName) {
         this.lastName = lastName;
     }

     public String getEmail() {
         return email;
     }
 
     public void setEmail(String email) {
         this.email = email;
     }
 
     public Department getDepartment() {
         return department;
     }
 
     public void setDepartment(Department department) {
         this.department = department;
     }

     @Override
     public String toString() {
         return "Employee [id=" + id + ", lastName=" + lastName + ", email="
                 + email + ", department=" + department + "]";
     }
     
     
 }

package com.yl.spring.jdbc;
 public class Department {
       private Integer id;
       private String name;
       public Integer getId() {
           return id;
       }
       public void setId(Integer id) {
           this.id = id;
       }
       public String getName() {
           return name;
       }
       public void setName(String name) {
           this.name = name;
       }
       @Override
       public String toString() {
           return "Department [id=" + id + ", name=" + name + "]";
       }      
       
   }

 package com.yl.spring.jdbc;
  import Java.sql.SQLException;
 import Java.util.ArrayList;
 import Java.util.List;
 
 import Javax.sql.DataSource;
 
 import org.junit.Test;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;
 import org.springframework.jdbc.core.BeanPropertyRowMapper;
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
 
 public class JDBCTest {
     
     private ApplicationContext ctx = null;
     private JdbcTemplate jdbcTemplate;
     private EmployeeDao employeeDao;
     
     {
         ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
         jdbcTemplate = (JdbcTemplate)ctx.getBean("jdbcTemplate");
         employeeDao = ctx.getBean(EmployeeDao.class);
     }
     
     @Test
     public void testEmployeeDao() {
         System.out.println(employeeDao.get(1));
     }
     
     /**
      * 获取单个列的值，或做统计查询
      */
     @Test
     public void testQueryForObject2() {
         String sql = "SELECT count(id) FROM employee";
         long count = jdbcTemplate.queryForObject(sql, Long.class);
         System.out.println(count);
     }
     
     /**
      * 查到实体类的集合
      */
     @Test
     public void testQueryForList() {
         String sql = "SELECT id, last_name, email FROM employee WHERE id > ?";
         RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<Employee>(Employee.class);
         List<Employee> employees = jdbcTemplate.query(sql, rowMapper, 5);
         System.out.println(employees);
     }
     
     /**
      * 从数据库中获取一条记录，实际得到对应的一个对象
      * 1.RowMapper指定如何映射结果集的行，常用的实现类为BeanPropertyRowMapper
      * 2.使用SQL中列的别名完成列名和类的属性名的映射。例如last_name和lastName
      * 3.不支持级联属性。JdbcTemplate到底是一个JDBC工具，不是ORM框架。
      */
     @Test
     public void TestForQueryObject() {
         String sql = "SELECT id, last_name, email FROM employee WHERE id = ?";
         RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<Employee>(Employee.class);
         
         Employee employee = jdbcTemplate.queryForObject(sql, rowMapper, 1);
         System.out.println(employee);
     }
     
     /**
      * 批量执行更新：批量的INSERT, UPDATE, DELETE
      * 最后一个参数是Object[]的list类型：因为修改一条记录需要一个Object的数组，那么多条就是需要多个Object的数组
      */
     @Test
     public void testBatchUpdate() {
         String sql = "INSERT INTO employee(id, last_name, email, dept_id) VALUES(?, ?, ?, ?)";
         List<Object[]> batchArgs = new ArrayList<Object[]>();
         batchArgs.add(new Object[]{6, "AA", "[email protected]", 1});
         batchArgs.add(new Object[]{7, "BB", "[email protected]", 2});
         batchArgs.add(new Object[]{8, "CC", "[email protected]", 3});
         batchArgs.add(new Object[]{9, "DD", "[email protected]", 3});
         batchArgs.add(new Object[]{10, "EE", "[email protected]", 2});
         jdbcTemplate.batchUpdate(sql, batchArgs);
     }
     
     /**
      * 执行INSERT, UPDATE, DELETE
      */
     @Test
     public void testUpdate() {
         String sql = "UPDATE employee SET last_name=? WHERE id=?";
         jdbcTemplate.update(sql, "Jack", 5);
     }
     
     @Test
     public void test() throws SQLException {
         DataSource dataSource = (DataSource)ctx.getBean("dataSource");
         System.out.println(dataSource.getConnection());
     }
 
 }