【原】JDBC工具类（DButil）

package lesson11;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class DBUtil {
private Connection conn = null;
private Statement st = null;
private PreparedStatement ps = null;
private ResultSet rs = null;
private String url = "jdbc:mysql://localhost:3306/filmcenter_db";
private String username = "root";
private String psw = "root";

//1.加载驱动
static{
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (ClassNotFoundException e) {
System.out.println("加载驱动失败！！");
e.printStackTrace();
}
}
//2.获取连接
public Connection getConn(){
try {
conn = DriverManager.getConnection(url,username,psw);
} catch (SQLException e) {
System.out.println("获取连接失败！！");
e.printStackTrace();
}
return conn;
}
//3.提供更新方法
public int update(String sql, Object[] objs){
conn = getConn();
try {
ps = conn.prepareStatement(sql);
for(int i = 0 ; i < objs.length ; i ++){
ps.setObject(i + 1, objs[i]);
}
return ps.executeUpdate();
} catch (SQLException e) {
System.out.println("更新失败！！");
e.printStackTrace();
return -1;
}finally{
release();
}
}
//4.提供查询方法
public List<Map<String,Object>> query(String sql, Object[] objs){
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
try {
ps = getConn().prepareStatement(sql);
for(int i = 0 ; i < objs.length ; i ++){
ps.setObject(i + 1, objs[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
while(rs.next()){
Map<String,Object> map = new HashMap<String,Object>();
for(int i = 0 ; i < rsmd.getColumnCount() ; i ++){
String key = rsmd.getColumnName(i + 1);
Object value = rs.getObject(key);
map.put(key, value);
}
list.add(map);
}
return list;
} catch (SQLException e) {
System.out.println("查询操作失败！");
e.printStackTrace();
return list;
}finally{
release();
}
}
//5.批量更新
public void batch(String[] sqls){
try {
conn = getConn();
conn.setAutoCommit(false);
st = conn.createStatement();
for(int i = 0; i < sqls.length ; i ++){
st.addBatch(sqls[i]);
}
st.executeBatch();
} catch (SQLException e) {
e.printStackTrace();
try {
conn.rollback();
} catch (SQLException e1) {
e1.printStackTrace();
}
}finally{
try {
conn.commit();
} catch (SQLException e) {
e.printStackTrace();
}
release();
}
}
//释放资源
public void release(){
if(rs != null){
try {
rs.close();
} catch (SQLException e) {
System.out.println("关闭结果集对象出现异常！");
e.printStackTrace();
}
}
if(ps != null){
try {
ps.close();
} catch (SQLException e) {
System.out.println("关闭预处理语句对象出现异常！");
e.printStackTrace();
}
}
if(st != null){
try {
st.close();
} catch (SQLException e) {
System.out.println("关闭语句对象出现异常！");
e.printStackTrace();
}
}
if(conn != null){
try {
conn.close();
} catch (SQLException e) {
System.out.println("关闭连接对象出现异常！");
e.printStackTrace();
}
}
}

}