使用c3p0连接池连接数据库

示例(mvc模式)

1.mysql.properties (连接数据库的)文件：

driver=com.mysql.jdbc.Driver

url=jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=UTC&characterEncoding=utf8&useUnicode=true

user=root

password=root

2.c3p0-config.xml 文件(配置在src根目录下)：

com.mysql.jdbc.Driver

jdbc:mysql:///test

root

root

5

10

com.mysql.jdbc.Driver

jdbc:mysql:///test

root

root

5

10

3.util 类：

public class JDBCUtils {

// 初始化连接池

private static DataSource dataSource;

static {

dataSource=new ComboPooledDataSource();

}

public static DataSource getDataSource() {

return dataSource;

}

/**

* 创建DbUtils常用工具类对象

*/

public static QueryRunner getQuerrRunner() {

return new QueryRunner(dataSource);

}

}

注意：区别

4.dao 层：

/**

* 2. 菜系模块，dao接口设计

*/

public interface StudentTypeDao {

public void save(StudentType studentType);//添加

public void update(StudentType studentType);//更新

public void delete(int id);//删除

public StudentType findById(int id);//根据主键查询

public ListgetAll();//查询全部

public ListgetAllForName(String sName);//根据名称查询

}

5.dao 的实现：

/**

* 2. 学生系模块dao实现

*/

public class StudentTypeDaoimpl implements StudentTypeDao{

@Override

public void save(StudentType studentType) {//增加

//SQL语句

String sql="insert into student_list(id,sName,sex,major,nianji) values(?,?,?,?,?)";

try {//抛异常

//把得到的值放入一个数组

Object params[]= {studentType.getId(),studentType.getsName(),

studentType.getSex(),studentType.getMajor(),studentType.getNianji()};

//调用util类的getQuerrRunner()方法

JDBCUtils.getQuerrRunner().update(sql,params);

} catch (Exception e) {

throw new RuntimeException(e);

}

}

@Override

public void update(StudentType studentType) {//更新

String sql="update student_list set sName=?,major=?,nianji=? where id=?";

try {

Object params[]={studentType.getsName(),

studentType.getMajor(),studentType.getNianji(),studentType.getId()};

JDBCUtils.getQuerrRunner().update(sql,params);

} catch (Exception e) {

throw new RuntimeException(e);

}

}

@Override

public void delete(int id) {

String sql="delete from student_list where id=?";

try {

JDBCUtils.getQuerrRunner().update(sql, id);

} catch (Exception e) {

throw new RuntimeException(e);

}

}

@Override

public StudentType findById(int id) {

String sql="select * from student_list where id=?";

try {

return JDBCUtils.getQuerrRunner().query(sql, new BeanHandler(StudentType.class), id);

} catch (Exception e) {

throw new RuntimeException(e);

}

}

@Override

public ListgetAll() {

String sql="select * from student_list";

try {

Listlist = JDBCUtils.getQuerrRunner().query(sql, new BeanListHandler(StudentType.class));

return list;

} catch (Exception e) {

throw new RuntimeException(e);

}

}

@Override

public ListgetAllForName(String sName) {

String sql="select * from student_list where sName like ?";

try {

return JDBCUtils.getQuerrRunner().query(sql, new BeanListHandler(StudentType.class), "%"+sName+"%");

} catch (Exception e) {;

throw new RuntimeException(e);

}

}

}

用到的jar包：

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