JdbcTemplate

Spring 框架對(duì) JDBC 進(jìn)行封裝鳞仙，使用 JdbcTemplate 方便實(shí)現(xiàn)對(duì)數(shù)據(jù)庫(kù)操作

配置如下

1.新建一個(gè)maven工程
2.一個(gè)User實(shí)體類、字段為userNo笔时、userName棍好、userSex、userAge,get 允耿、set方法
3.一個(gè)測(cè)試類
4.一個(gè)User表,字段 userName借笙、userSex、userAge较锡、userNo
5.ApplicationContext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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd">

<!--    數(shù)據(jù)源-->
    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>
        <property name="url" value="jdbc:mysql://192.168.x.x:3306/school?characterEncoding=utf8&amp;useSSL=false"/>
        <property name="username" value="root"/>
        <property name="password" value="xxR)xx97aod_oJxx!"/>
    </bean>

<!--    引用數(shù)據(jù)源-->
    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
        <property name="dataSource" ref="dataSource"></property>
    </bean>
</beans>

實(shí)操代碼

新增數(shù)據(jù)：?代表具體占位符业稼，updata后的參數(shù)是sql里面的值，根據(jù)順序排列

BeanFactory factory = new ClassPathXmlApplicationContext("ApplicationContext.xml");
        JdbcTemplate jdbcTemplate = (JdbcTemplate) factory.getBean("jdbcTemplate");

        String sql = "INSERT INTO `school`.`User`(`userNo`, `userName`, `userAge`, `userSex`) VALUES (?, ?, ?, ?);";
        int count = jdbcTemplate.update(sql,2005,"兩三",211,"男");
        System.out.println(count);//表示被修改的數(shù)據(jù)的條數(shù)蚂蕴，因?yàn)樾略鲆粭l結(jié)果為0

刪除數(shù)據(jù)：

        String sqldelete = "delete from `school`.`User` where userNo = ?";
        int countdelete = jdbcTemplate.update(sqldelete,2004);
        System.out.println(countdelete);//同新增低散，如果刪除的id不存在則條數(shù)為0

更新數(shù)據(jù)：

        String sqlUpdate = "update `school`.`User` set userName=?,userSex=?,userAge=? where userNo=?;";
        int countUpdate = jdbcTemplate.update(sqlUpdate,"八兩","女",21,2005);
        System.out.println(countUpdate);

查詢數(shù)據(jù)：

queryForObject()只能查詢一列

       String sqlselectOne = "select userName from `school`.`User` where userNo = ?";
        String userName = jdbcTemplate.queryForObject(sqlselectOne,String.class,2005);
        System.out.println(userName);

queryForObject()可以查詢所有列，但是需要給個(gè)策略（什么值賦值到什么字段）

       //查所有字段
        String sqlselect = "select * from `school`.`User` where userNo = ?";
        //new RowMapper<User>()實(shí)現(xiàn)這個(gè)接口中的方法骡楼，給一個(gè)策略
        User user =jdbcTemplate.queryForObject(sqlselect, new RowMapper<User>() {
            @Override
            public User mapRow(ResultSet rs, int rowNum) throws SQLException {
                User user = new User();
                user.setUserNo(rs.getInt("userNo"));
                user.setUserAge(rs.getInt("userAge"));
                user.setUserName(rs.getString("userName"));
                user.setUserSex(rs.getString("userSex"));
                return user;
            }
        }, 2005);
        System.out.println(user);

queryForList()查詢多行數(shù)據(jù)

        String sqls = "select * from `school`.`User`";
        //queryForList方法存入map中熔号，不需要給策略
        List<Map<String, Object>> list = jdbcTemplate.queryForList(sqls);
        System.out.println(list);

query()查詢多行數(shù)據(jù)

public class Celue implements RowMapper {
    @Override
    public User mapRow(ResultSet rs, int rowNum) throws SQLException {
        User user = new User();
        user.setUserNo(rs.getInt("userNo"));
        user.setUserAge(rs.getInt("userAge"));
        user.setUserName(rs.getString("userName"));
        user.setUserSex(rs.getString("userSex"));
        return user;
    }
}

        String sqls = "select * from `school`.`User`";
        //query存入實(shí)體類對(duì)象，需要給策略（什么值存入什么字段中）
        List<User> list1 = jdbcTemplate.query(sqls,new Celue());
        System.out.println(list1);