spring操作数据库

1、JdbcTemplate

spring对数据库的操作在jdbc上做了更深层次的封装JdbcTemplate，处理了资源的建立和释放(不需要我们管理连接了),我们只需要提供SQL语句(不需要我们设置参数了)和提取结果(查询时候可以直接返回对应的实体类),使JDBC更加易于使用。它也可以使用spring的注入功能，将数据源注入JdbcTemplate，来实现操作数据库。

2、JdbcTemplate常用方法

• update(更新数据)
• batchUpdate(批量更新数据)
• queryForObject(查询单行数据或者单值数据)

• query(查询多行数据)

  3、Spring中实现jdbcTemplate对数据库操作(采用c3p0连接池)

  1、需要导入的jar包

• spring-jdbc-5.0.6.RELEASE.jar
• spring-tx-5.0.6.RELEASE.jar
• mysql-connector-java-5.0.7.jar

• c3p0-0.9.5.2.jar

  2、springxml配置

    <context:property-placeholder
            location="classpath:jdbc.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>
        </bean>
  
        <!-- 将c3p0数据源注入jdbcTemplate -->
        <bean id="jdbcTemplate"
            class="org.springframework.jdbc.core.JdbcTemplate">
            <property name="dataSource" ref="dataSource"></property>
        </bean>

  3、User实体类

    public class User {
  
        private int id;
        private String username;
        private String password;
  
        public User() {
            super();
        }
  
        public int getId() {
            return id;
        }
  
        public void setId(int id) {
            this.id = id;
        }
  
        public String getUsername() {
            return username;
        }
  
        public void setUsername(String username) {
            this.username = username;
        }
  
        public String getPassword() {
            return password;
        }
  
        public void setPassword(String password) {
            this.password = password;
        }
  
        @Override
        public String toString() {
            return "User [id=" + id + ", username=" + username + ", password=" + password + "]";
        }
  
    }

  4、测试类

    public void testUserServiceImpl() {
            //获取IOC容器
            ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");    
  
            //通过ApplicationContext对象的getBean方法来获取对象实例
            //获取数据连接模板JdbcTemplate
            JdbcTemplate jdbcTemplate = (JdbcTemplate) context.getBean("jdbcTemplate");
  
            //增加
            String sql1 = "insert into user(username,password) values(?,?)";
            System.out.println(jdbcTemplate.update(sql1, "user","user123"));
  
            //修改
            String sql2 = "update user set username = ? where id = 10000";
            System.out.println(jdbcTemplate.update(sql2, "adminadmin"));
  
            //查询基本数据
            String sql3 = "select count(*) from user";
            System.out.println(jdbcTemplate.queryForObject(sql3, Integer.class));
  
            //查询单条记录
            String sql4 = "select * from user where id = 10000";
            RowMapper<User> rowMapper = new BeanPropertyRowMapper<>(User.class);
            User user = jdbcTemplate.queryForObject(sql4, rowMapper);
            System.out.println(user);
  
            //查询多条记录
            String sql5 = "select * from user";
            List<User> list = jdbcTemplate.query(sql5, rowMapper);
            for (User user2 : list) {
                System.out.println(user2);
            }
  
            //批量插入
            String sql6 = "insert into user(username,password) values(?,?)";
            List<Object[]> batchArgs=new ArrayList<Object[]>();
            batchArgs.add(new Object[]{"aaaa","aaa123"});
            batchArgs.add(new Object[]{"bbbb","bbb123"});
            batchArgs.add(new Object[]{"cccc","ccc123"});
            jdbcTemplate.batchUpdate(sql6, batchArgs);
        }