Spring Data_学习记录_03

布满荆棘的人生 2022-02-25 00:30 199阅读 0赞

### 1. Using Jdbc Template ###

*  org.zcs.springjdbc - JdbcDemo.java

package org.zcs.springjdbc;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    import org.zcs.springjdbc.dao.JdbcDaoImpl;
    import org.zcs.springjdbc.model.Circle;
    
    public class JdbcDemo { 
    	public static void main(String[] args) { 
    		ApplicationContext ctx = new ClassPathXmlApplicationContext("spring.xml");
    		JdbcDaoImpl dao = ctx.getBean("jdbcDaoImpl", JdbcDaoImpl.class);
    		//Circle circle = dao.getCircle(1);
    		//System.out.println(circle.getName());
    		System.out.println(dao.getCircleCount());
    	}
    }

*  org.zcs.springjdbc.dao-JdbcDaoImpl.java

package org.zcs.springjdbc.dao;
    
    import java.sql.Connection;
    import java.sql.DriverManager;
    import java.sql.PreparedStatement;
    import java.sql.ResultSet;
    import java.sql.SQLException;
    
    import javax.sql.DataSource;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.jdbc.core.JdbcTemplate;
    import org.springframework.stereotype.Component;
    import org.zcs.springjdbc.model.Circle;
    
    import com.mysql.jdbc.Statement;
    @Component
    public class JdbcDaoImpl { 	
    
    	private DataSource dataSource;
    	private JdbcTemplate jdbcTemplate = new JdbcTemplate();
    	
    	
    	public Circle getCircle(int circleId) { 
    	
    			
    	        try { 
     
    	        Connection con = (Connection) dataSource.getConnection(); //连接数据库
     
    	        String sql = "Select * from springdata where id = ?";//对表的操作语句
    	        PreparedStatement ps = con.prepareStatement(sql);
    	        ps.setInt(1, circleId);
    	        Circle circle = null;
    	        ResultSet rs = ps.executeQuery();
    	        if(rs.next()) { 
    	        	circle = new Circle(circleId, rs.getString("name"));
    	        }
    	       
    	        rs.close();
    	        
    	        ps.close();
    	        con.close();
    	        return circle;
    	        
    	        }catch (Exception e) { 
    	        	throw new RuntimeException(e);
    	        } 
    	}
    
    	 
    	public int getCircleCount() { 
    		String sql = "SELECT COUNT(*) FROM springdata";
    		jdbcTemplate.setDataSource(getDataSource());
    		return jdbcTemplate.queryForObject(sql, Integer.class);
    	}
    	public DataSource getDataSource() { 
    		return dataSource;
    	}
    
    	@Autowired
    	public void setDataSource(DataSource dataSource) { 
    		this.dataSource = dataSource;
    	}
    
    
    	public JdbcTemplate getJdbcTemplate() { 
    		return jdbcTemplate;
    	}
    
    
    	public void setJdbcTemplate(JdbcTemplate jdbcTemplate) { 
    		this.jdbcTemplate = jdbcTemplate;
    	}
    }

*  org.zcs.springjdbc.model-Circle.java

package org.zcs.springjdbc.model;
    
    public class Circle { 
    	public int id;
    	public String name;
    	public int getId() { 
    		return id;
    	}
    	public void setId(int id) { 
    		this.id = id;
    	}
    	public String getName() { 
    		return name;
    	}
    	public void setName(String name) { 
    		this.name = name;
    	}
    	public Circle(int circleId, String name) { 
    		setId(circleId);
    		setName(name);
    }
    }

*  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:p="http://www.springframework.org/schema/p" 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">
    
     	<context:annotation-config></context:annotation-config>
    
     	<context:component-scan base-package="org.zcs.springjdbc"></context:component-scan>
    
        
    	<bean id = "dataSource" class = "org.springframework.jdbc.datasource.DriverManagerDataSource">
    			<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
    			<property name="url" value="jdbc:mysql://172.21.3.210:3306/data1?useSSL=false"></property>
    			<property name="username" value="MHadoop"></property>
    			<property name="password" value="12345678"></property>
    	</bean>
    </beans>

### 2.学习记录 ###

*  本次学习了spring jdbc的 Template 的使用方法
 *  遇到一个过期的问题`jdbcTemplate.queryForInt(sql)`;改成这个就可以了`jdbcTemplate.queryForObject(sql, Integer.class);`