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;
 
     }
 
 }