jdbc萬能操作模塊

本文介紹通過Spring的動態配置，實現在不同的pojo類和數據庫表間切換，表結構如下：

1. spring配置文件如下：

<?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: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-2.0.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd"> <!-- 配置一個數據源 --> <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/xwh" /> <property name="username" value="root" /> <property name="password" value="root" /> </bean> <!-- 配置一個SimpleJdbcTemplate模板 --> <bean id="simpleJdbcTemplate" class="org.springframework.jdbc.core.simple.SimpleJdbcTemplate"> <constructor-arg ref="datasource"/> </bean> <!-- 在這裏修改表名和實體名，就能對相應的表和實體進行增、刪、改、查操作 --> <bean id="myDao" class="com.page.impl.MyDao"> <property name="INSERTSQL" value="insert into student values(?,?,?)"/> <property name="QUERYTSQL" value="SELECT * FROM student"/> <property name="jdbcTemplate" ref="simpleJdbcTemplate" /> <property name="tableName" value="student"/> <property name="entityObject" ref="student"/> </bean> <bean id="student" class="com.page.impl.Student"> <property name="id" value="2"/> <property name="name" value="b"/> <property name="score" value="92.0"></property> </bean> <bean id="teacher" class="com.page.impl.Teacher"> <property name="id" value="2"/> <property name="name" value="b"/> </bean> </beans>

2.新建DAO類（精髓所在）

package com.page.impl; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.sql.ResultSet; import java.sql.SQLException; import java.util.List; import org.apache.commons.beanutils.BeanUtils; import org.springframework.jdbc.core.simple.ParameterizedRowMapper; import org.springframework.jdbc.core.simple.SimpleJdbcTemplate; public class MyDao { String INSERTSQL;// 查 String QUERYTSQL;// 增 , 刪 ,改 SimpleJdbcTemplate jdbcTemplate; String tableName;// 需要操作的數據庫表名 Object entityObject;// 需要操作的實體對象名 /* * Spring注入 */ public void setINSERTSQL(String insertsql) { INSERTSQL = insertsql; } /* * Spring注入 */ public void setQUERYTSQL(String querytsql) { QUERYTSQL = querytsql; } /* * Spring注入 */ public void setJdbcTemplate(SimpleJdbcTemplate jdbcTemplate) { this.jdbcTemplate = jdbcTemplate; } /* * Spring注入 */ public void setTableName(String tableName) { this.tableName = tableName; } /* * Spring注入 */ public void setEntityObject(Object entityObject) { this.entityObject = entityObject; } public String getTableName() { return tableName; } public Object getEntityObject() { return entityObject; } public String getQUERYTSQL() { return QUERYTSQL; } public String getINSERTSQL() { return INSERTSQL; } public SimpleJdbcTemplate getJdbcTemplate() { return jdbcTemplate; } public void initData() { System.out.println("開始初始化測試數據"); Field[] fields = entityObject.getClass().getDeclaredFields(); Object[] objs = new Object[fields.length]; for (int i = 0; i < objs.length; i++) { try { objs[i] = BeanUtils.getProperty(entityObject, fields[i].getName()); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } } System.out.println(INSERTSQL); this.getJdbcTemplate().update(INSERTSQL, objs); System.out.println("測試數據初始化成功"); } public List<Object> queryData() { System.out.println("開始查詢數據表"); List<Object> listObject = this.jdbcTemplate.query(QUERYTSQL, new ParameterizedRowMapper<Object>() { public Object mapRow(ResultSet rs, int rowNum) throws SQLException { Field[] fields = entityObject.getClass().getDeclaredFields(); Object obj = new Object(); ; try { obj = entityObject.getClass().newInstance(); } catch (InstantiationException e1) { e1.printStackTrace(); } catch (IllegalAccessException e1) { e1.printStackTrace(); } for (int i = 0; i < fields.length; i++) { try { Object temp = getData(fields[i].getType().getName(), rs, i + 1); BeanUtils.copyProperty(obj, fields[i].getName(), temp); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } return obj; } }); System.out.println("完成數據表查詢"); return listObject.size() > 0 ? listObject : null; } public Object getData(String fldType, ResultSet rs, int i) throws Exception { if ("int".equals(fldType)) { return rs.getInt(i); } else if ("java.lang.String".equals(fldType)) { return rs.getString(i); } else if ("float".equals(fldType)) { return rs.getFloat(i); } else if ("double".equals(fldType)) { return rs.getDouble(i); } else if ("long".equals(fldType)) { return rs.getLong(i); } else { return null; } } }

3.新建spring容器類

package com.page.impl.spring; import org.springframework.beans.factory.BeanFactory; import org.springframework.context.support.ClassPathXmlApplicationContext; public class SpringContainer { static BeanFactory factory; public static void init() { factory = new ClassPathXmlApplicationContext("spring*.xml"); } public static Object getBean(String beanName) { if(null == factory) { init(); } return factory.getBean(beanName); } }

3.新建測試類

package com.page.impl; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.util.List; import org.apache.commons.beanutils.BeanUtils; import com.page.impl.spring.SpringContainer; public class Test extends SpringContainer { public static void main(String[] args) { MyDao myDao = (MyDao)getBean("myDao"); myDao.initData(); List<Object> list = myDao.queryData(); show(list); } public static void show(List<Object> list) { for(Object obj : list) { Field[] fields = obj.getClass().getDeclaredFields(); for(int i = 0; i < fields.length; i++) { try { System.out.print(fields[i].getName() + " = " + BeanUtils.getProperty(obj, fields[i].getName()) + ";"); } catch (IllegalAccessException e) { e.printStackTrace(); } catch (InvocationTargetException e) { e.printStackTrace(); } catch (NoSuchMethodException e) { e.printStackTrace(); } } System.out.println(); } System.out.println(); } }