package hzvtc.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.ResultSetHandler;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
public class DbHelper {
private String dbms; // 数据库类型
private String dbmsDriver; // 数据库驱动
private String host; // 主机
private String port; // 端口
private String db; // 数据库名
private String user; // 用户名
private String password; // 密码
private Class beanClass = null;
private Connection conn = null;
private final Log logger = LogFactory.getLog(DbHelper.class);
/**
* 根据数据库类型设置驱动程序
* @param dbms 数据库类型，如mysql、postgresql等
*/
private void fillDbmsDriver(String dbms) {
if (dbms.equalsIgnoreCase("postgresql"))
dbmsDriver = "org.postgresql.Driver";
else if (dbms.equalsIgnoreCase("mysql"))
dbmsDriver = "org.gjt.mm.mysql.Driver";
}
/**
* 根据数据库类型设置端口
* @param dbms 数据库类型
*/
private void fillDbmsPort(String dbms) {
if (dbms.equalsIgnoreCase("postgresql"))
port = "5432";
else if (dbms.equalsIgnoreCase("mysql"))
port = "3306";
}
/**
* 设置数据连接时需要的参数
* @param dbms 数据库类型
* @param host 主机
* @param db 数据库名
* @param user 用户名
* @param password 密码
*/
public DbHelper(String dbms, String host, String db, String user,
String password) {
this.dbms = dbms;
fillDbmsDriver(dbms);
this.host = host;
fillDbmsPort(dbms);
this.db = db;
this.user = user;
this.password = password;
}
/**
* 设置数据连接时需要的参数
* @param dbms 数据库类型
* @param host 主机
* @param port 端口
* @param db 数据库名
* @param user 用户
* @param password 密码
*/
public DbHelper(String dbms, String host, String port, String db,
String user, String password) {
this.dbms = dbms;
fillDbmsDriver(dbms);
this.host = host;
this.port = port;
this.db = db;
this.user = user;
this.password = password;
}
/**
* 加载驱动
*/
public void connect() {
if (conn != null) return;
String strConn =
String.format("jdbc:%s://%s:%s/%s", dbms, host, port, db);
DbUtils.loadDriver(dbmsDriver);
try {
conn = DriverManager.getConnection(strConn, user, password);
} catch (SQLException e) {
logger.error("Database connection failed!");
logger.error(e.getMessage());
}
}
/**
* 关闭Connection
*/
public void close() {
try {
DbUtils.close(conn);
conn = null;
} catch (SQLException e) {
logger.error("Database close failed!");
logger.error(e.getMessage());
}
}
/**
* 根据无参sql语句进行查询，并返回一个对象，用于单条记录的查询
* @param sql
* @return Object
*/
public Object query(String sql) {
if (conn == null || beanClass == null)
return null;
QueryRunner run = new QueryRunner();
ResultSetHandler h = new BeanHandler(beanClass);
Object result = null;
try {
result = run.query(conn, sql, h);
} catch (SQLException e) {
logger.info("SQLException in [" + sql + "]");
logger.error(e.getMessage());
}
return result;
}
/**
* 根据有参sql语句进行查询，并返回一个对象，用于单条记录的查询
* @param sql
* @param args
* @return Object
*/
public Object query(String sql, Object... args) {
if (conn == null || beanClass == null)
return null;
QueryRunner run = new QueryRunner();
ResultSetHandler h = new BeanHandler(beanClass);
Object result = null;
try {
result = run.query(conn, sql, args, h);
} catch (SQLException e) {
logger.info("SQLException in [" + sql + "]");
logger.error(e.getMessage());
}
return result;
}
/**
* 根据无参sql语句进行查询，并返回一个数据集，用于多条记录的查询
* @param sql
* @return ArrayList
*/
public ArrayList queryRecords(String sql) {
if (conn == null || beanClass == null)
return null;
QueryRunner run = new QueryRunner();
ResultSetHandler h = new BeanListHandler(beanClass);
ArrayList result = null;
try {
result = (ArrayList) run.query(conn, sql, h);
// obtain the quaried records
} catch (SQLException e) {
logger.info("SQLException in [" + sql + "]");
logger.error(e.getMessage());
}
return result;
}
/**
* 根据有参sql语句进行查询，并返回一个数据集，用于多条记录的查询
* @param sql
* @param args
* @return
*/
public ArrayList queryRecords(String sql, Object... args) {
if (conn == null || beanClass == null)
return null;
QueryRunner run = new QueryRunner();
ResultSetHandler h = new BeanListHandler(beanClass);
ArrayList result = null;
try {
result = (ArrayList) run.query(conn, sql, args, h);
System.out.println(result.size());
// obtain the quaried records
} catch (SQLException e) {
logger.info("SQLException in [" + sql + "]");
logger.error(e.getMessage());
}
return result;
}
/**
* 根据无参sql语句进行数据更新，并返回更新后影响的记录数
* @param sql
* @return int
*/
public int update(String sql) {
if (conn == null)
return 0;
QueryRunner run = new QueryRunner();
int result = 0;
try {
result = run.update(conn, sql);
} catch (SQLException e) {
logger.info("SQLException in [" + sql + "]");
logger.error(e.getMessage());
}
return result;
}
/**
* 根据有参sql语句进行数据更新，并返回更新后影响的记录数
* @param sql
* @param args
* @return int
*/
public int update(String sql, Object... args) {
if (conn == null)
return -1;
QueryRunner run = new QueryRunner();
int result = 0;
try {
result = run.update(conn, sql, args);
} catch (SQLException e) {
logger.info("SQLException in [" + sql + "]");
logger.error(e.getMessage());
}
return result;
}
/**
* 设置存放查询结果的Bean类，每个Bean类对象对应一条查询的结果记录
* @param beanClass，如User.class
*/
public void setBeanClass(Class beanClass) {
this.beanClass = beanClass;
}
/**
* 设置使用外部的Connection对象，如来自数据库连接池的连接
* @param conn Connection对象
*/
public void setConn(Connection conn) {
this.conn = conn;
}
@Override
protected void finalize() throws Throwable {
// TODO Auto-generated method stub
close();
super.finalize();
}
}
DbTest
package hzvtc.util.test;
import hzvtc.util.DbHelper;
import java.util.List;
public class DbTest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
int n = 3;
DbHelper dh = new DbHelper("mysql", "localhost", "test", "root", "123456");
dh.connect();
dh.setBeanClass(User.class);
//u是从数据库查询出来的记录对象
User u = (User) dh.query("SELECT id,name,age,address FROM t_user WHERE id=9");
//u2是从数据库查询出来的记录对象
User u2 = (User) dh.query("SELECT id,name,age,address FROM t_user WHERE id=?", n);
// users和user2存放着从数据库查询出来的记录对象集合
List users = dh.queryRecords("SELECT id,name,age,address FROM t_user");
List users2 = dh.queryRecords("SELECT id,name,age,address FROM t_user WHERE id>?", n);
//修改表记录
dh.update("UPDATE t_user SET name='abc' WHERE id=9");
//根据提供的参数修改表记录
dh.update("UPDATE t_user SET name='abc' WHERE id=?", n);
dh.close();
}
}
