spring学习笔记之---JDBC Template

JDBC  Template（简化持久化操作）

（一）创建项目

（1）Maven配置

<dependencies>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.41</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-tx</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-aop -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-jdbc</artifactId>
        <version>5.1.5.RELEASE</version>
    </dependency>
  <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.1.5.RELEASE</version>
  </dependency>

</dependencies>

（2）spring配置

在resource中创建一个spring.xml文件

spring.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:aop="http://www.springframework.org/schema/aop"

       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/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">

 <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">

     <property name="driverClassName" value="com.mysql.jdbc.Driver"/>

     <property name="url" value="jdbc:mysql://localhost:3306/zml?useUnicode=true&amp;characterEncoding=utf-8"/>

     <property name="username" value="root"/>

     <property name="password" value="root"/>

 </bean>

    <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">

        <property name="dataSource" ref="dataSource" ></property>

    </bean>

</beans>

（二）JDBC  Template基本使用

（三）update和batchupdate

（1）使用方法

（2）实例

public class UserTest {
//创建jdbcTemplate对象，调用方法

    private JdbcTemplate jdbcTemplate;

    {

        ApplicationContext context=new ClassPathXmlApplicationContext("spring.xml");

        jdbcTemplate=(JdbcTemplate)context.getBean("jdbcTemplate");

    }

    //增加

    public void add1(){

        String sql="insert into users values(null,?,?)";

        jdbcTemplate.update(sql,"小木","123");

    }

    //修改

    public void update1(){

        String sql="update users set password=? where username=?";

        jdbcTemplate.update(sql,new Object[]{"123456","张三"});

    }

    //删除

    public void delete1(){

        String sql="delete from users where username=?";

        jdbcTemplate.update(sql,"李四");

    }

    //批量增加,修改，删除

    public void batchUpdate(){

        String[] sql={

                "insert into users values(null,'小花','123')",

                "insert into users values(null,'喵喵','123')",

                "update users set password='123456' where username='小木'",

                "delete from users where username='zhang'"

        };

        jdbcTemplate.batchUpdate(sql);

    }

    //批量增加

    @Test

    public void batchUpdate2(){

        String sql="insert into users values(null,?,?)";

        List<Object[]> list=new ArrayList<Object[]>();

        list.add(new Object[]{"哈哈","123"});

        list.add(new Object[]{"小黑","123"});

        list.add(new Object[]{"沐沐","123"});

        jdbcTemplate.batchUpdate(sql,list);

    }

}

（四）查询

（1）查询简单数据项

（a）使用方法

（b）实例

//查询密码为123的所有用户的用户名

   public void select(){

        String sql="select username from users where password=?";

        List<String> li=jdbcTemplate.queryForList(sql, String.class,"123");

       System.out.println(li);

   }

   //查询用户有几人

    public void selectcount(){

       String sql="select count(*) from users ";

       int list=jdbcTemplate.queryForObject(sql,Integer.class);

       System.out.println(list);

   }

（2）查询复杂对象

（a）使用方法

（b）实例

//查询用户名为喵喵的用户的所有信息

 public void selectname(){

     String sql="select * from users where username=?";

     Map<String ,Object> map=jdbcTemplate.queryForMap(sql, "喵喵");

     System.out.println(map);

 }

 //查询所有用户的所有信息

 public void selectall(){

     String sql="select * from users ";

     List<Map<String ,Object>> map=jdbcTemplate.queryForList(sql);

     System.out.println(map);

 }

 //查询后返回一个实体对象

 public void selectone(){

     String sql="select * from users where username=?";

     Users users=jdbcTemplate.queryForObject(sql,new UserRowMapper(),"小花");

     System.out.println(users);

 }

 //查询所有用户信息,实体封装

 @Test

 public void selectAll(){

     String sql="select * from users ";

     List<Users> us=jdbcTemplate.query(sql,new UserRowMapper());

     System.out.println(us);

 }
//将RowMapper分离，简化代码

 private class UserRowMapper implements RowMapper<Users> {

     @Override

     public Users mapRow(ResultSet resultSet, int i) throws SQLException {

         Users u = new Users();

         u.setId(resultSet.getInt("id"));

         u.setUsername(resultSet.getString("username"));

         u.setPassword(resultSet.getString("password"));

         return u;

     }

 }