Spring对JdbcTemplate简单操作

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/hundan_520520/article/details/81705955

注：参考尚硅谷spring4教程

导入spring4所需的jar和数据库连接jar

db.properties

jdbc.user=root
jdbc.password=root
jdbc.driverClass=com.mysql.jdbc.Driver
jdbc.jdbcUrl=jdbc:mysql://127.0.0.1:3306/atguigu?useSSL=false&useUnicode=true&characterEncoding=utf-8

jdbc.initPoolSize=5
jdbc.maxPoolSize=10

applicationContext.xml

<?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"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd">

    <context:component-scan base-package="com.zhihua.spring"></context:component-scan>

    <!-- 导入资源文件 -->
    <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="jdbcUrl" value="${jdbc.jdbcUrl}"></property>
        <property name="driverClass" value="${jdbc.driverClass}"></property>

        <property name="initialPoolSize" value="${jdbc.initPoolSize}"></property>
        <property name="maxPoolSize" value="${jdbc.maxPoolSize}"></property>
    </bean>

    <!-- 配置 Spirng 的 JdbcTemplate -->
    <bean id="jdbcTemplate" 
        class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>

    <!-- 配置 NamedParameterJdbcTemplate, 该对象可以使用具名参数, 其没有无参数的构造器, 所以必须为其构造器指定参数 -->
    <bean id="namedParameterJdbcTemplate"
        class="org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate">
        <constructor-arg ref="dataSource"></constructor-arg>    
    </bean>

</beans>

模拟两个实体类
Employee.java

package com.zhihua.spring;

public class Employee {

    private Integer id;
    private String lastName;
    private String email;

    private Integer deptId;

    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 Integer getDeptId() {
        return deptId;
    }

    public void setDeptId(Integer deptId) {
        this.deptId = deptId;
    }

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

}

Department.java

package com.zhihua.spring;

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 + "]";
    }
}

直接注入jdbcTemplate和继承JdbcDaoSupport
EmployeeDao.java

package com.zhihua.spring;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.stereotype.Repository;

@Repository
public class EmployeeDao {

    @Autowired
    private JdbcTemplate jdbcTemplate;

    public Employee get(Integer id) {
        String sql = "SELECT id, last_name lastName, email FROM employees WHERE id = ?";
        RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
        Employee employee = jdbcTemplate.queryForObject(sql, rowMapper,id);
        return employee;
    }
}

DepartmentDao.java

package com.zhihua.spring;

import javax.sql.DataSource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.support.JdbcDaoSupport;
import org.springframework.stereotype.Repository;

/**
 * 不推荐使用 JdbcDaoSupport, 而推荐直接使用 JdbcTempate 作为 Dao 类的成员变量
 * @author caizh
 *
 */
@Repository
public class DepartmentDao extends JdbcDaoSupport{

    /**
     * 要再手动注入dataSource，或者jdbcTemplate
     * @param dataSource
     */
    @Autowired
    public void setDataSource2(DataSource dataSource){
        setDataSource(dataSource);
    }

    public Department get(Integer id){
        String sql = "SELECT id, dept_name name FROM departments WHERE id = ?";
        RowMapper<Department> rowMapper = new BeanPropertyRowMapper<>(Department.class);
        Department department = new Department();
        try {
            department = getJdbcTemplate().queryForObject(sql, rowMapper, id);
        } catch (Exception e) {
            return null;
        }               
        return department;
    }
}

测试类

package com.zhihua.spring;

import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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;
import org.springframework.jdbc.core.namedparam.BeanPropertySqlParameterSource;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;

public class JDBCTest {

    private ApplicationContext ctx = null;
    private JdbcTemplate jdbcTemplate;
    private EmployeeDao employeeDao;
    private DepartmentDao departmentDao;
    // 可以有具名参数的jdbctemplate
    private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

    {
        ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        jdbcTemplate = (JdbcTemplate) ctx.getBean("jdbcTemplate");
        employeeDao = (EmployeeDao) ctx.getBean("employeeDao");
        departmentDao = (DepartmentDao) ctx.getBean("departmentDao");
        namedParameterJdbcTemplate = (NamedParameterJdbcTemplate) ctx.getBean("namedParameterJdbcTemplate");
    }

    /**
     * 1.测试数据库连接
     * @throws SQLException
     */
    @Test
    public void testDataSource() throws SQLException {
        DataSource dataSource = ctx.getBean(DataSource.class);
        System.out.println(dataSource.getConnection());
    }

    /**
     * 执行 INSERT, UPDATE, DELETE
     */
    @Test
    public void testUpdate(){
        String sql = "UPDATE employees SET last_name = ? WHERE id = ?";
        jdbcTemplate.update(sql, "Jack", 5);
    }

    /**
     * 执行批量更新: 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, 那么多条不就需要多个 Object 的数组吗
     */
    @Test
    public void testBatchUpdate() {
        String sql = "INSERT INTO employees(last_name, email, dept_id) VALUES(?,?,?)";
        List<Object[]> batchArgs = new ArrayList<>();
        batchArgs.add(new Object[]{"AA", "[email protected]", 1});
        batchArgs.add(new Object[]{"BB", "[email protected]", 2});
        batchArgs.add(new Object[]{"CC", "[email protected]", 3});
        batchArgs.add(new Object[]{"DD", "[email protected]", 3});
        batchArgs.add(new Object[]{"EE", "[email protected]", 2});

        jdbcTemplate.batchUpdate(sql,batchArgs);
    }

    /**
     * 从数据库中获取一条记录, 实际得到对应的一个对象
     * 注意不是调用 queryForObject(String sql, Class<Employee> requiredType, Object... args) 方法!
     * 而需要调用 queryForObject(String sql, RowMapper<Employee> rowMapper, Object... args)
     * 1. 其中的 RowMapper 指定如何去映射结果集的行, 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 lastName
     * 3. 不支持级联属性. JdbcTemplate 到底是一个 JDBC 的小工具, 而不是 ORM 框架
     */
    @Test
    public void testQueryForObject() {
        String sql = "SELECT id, last_name lastName, email FROM employees WHERE id = ?";
        RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
        Employee employee = jdbcTemplate.queryForObject(sql, rowMapper,1);
        System.out.println(employee.toString());
    }

    /**
     * 查到实体类的集合
     */
    @Test
    public void testQueryForList() {
        String sql = "SELECT id, last_name lastName, email FROM employees WHERE id = ? and last_name=?";
        List<Map<String,Object>> employees = jdbcTemplate.queryForList(sql, new Object[] {1,"AA"});
        System.out.println(employees);
    }

    /**
     * 查到实体类的集合
     * 注意调用的不是 queryForList 方法
     */
    @Test
    public void testQuery() {
        String sql = "SELECT id, last_name lastName, email FROM employees WHERE id > ?";
        RowMapper<Employee> rowMapper = new BeanPropertyRowMapper<>(Employee.class);
        List<Employee> employees = jdbcTemplate.query(sql, rowMapper,1);
        System.out.println(employees);
    }

    /**
     * 获取单个列的值, 或做统计查询
     * 使用 queryForObject(String sql, Class<Long> requiredType) 
     */
    @Test
    public void testQueryForObject2() {
        String sql = "SELECT count(id) FROM employees";
//      long count = jdbcTemplate.queryForLong(sql);
        long count = jdbcTemplate.queryForObject(sql, Long.class);
        System.out.println(count);
    }

    @Test
    public void testEmployeeDao(){
        System.out.println(employeeDao.get(1));
    }

    @Test
    public void testDepartmentDao(){
        System.out.println(departmentDao.get(1));
    }

    /**
     * 可以为参数起名字. 
     * 1. 好处: 若有多个参数, 则不用再去对应位置, 直接对应参数名, 便于维护
     * 2. 缺点: 较为麻烦. 
     */
    @Test
    public void testNamedParameterJdbcTemplate(){
        String sql = "INSERT INTO employees(last_name, email, dept_id) VALUES(:ln,:email,:deptid)";

        Map<String, Object> paramMap = new HashMap<>();
        paramMap.put("ln", "FF");
        paramMap.put("email", "[email protected]");
        paramMap.put("deptid", 2);

        namedParameterJdbcTemplate.update(sql, paramMap);
    }

    /**
     * 使用具名参数时, 可以使用 update(String sql, SqlParameterSource paramSource) 方法进行更新操作
     * 1. SQL 语句中的参数名和类的属性一致!
     * 2. 使用 SqlParameterSource 的 BeanPropertySqlParameterSource 实现类作为参数. 
     */
    @Test
    public void testNamedParameterJdbcTemplate2(){
        String sql = "INSERT INTO employees(last_name, email, dept_id) "
                + "VALUES(:lastName,:email,:deptId)";

        Employee employee = new Employee();
        employee.setLastName("XYZ");
        employee.setEmail("[email protected]");
        employee.setDeptId(3);

        SqlParameterSource paramSource = new BeanPropertySqlParameterSource(employee);
        namedParameterJdbcTemplate.update(sql, paramSource);
    }
}