JDBCUtils工具包
JDBCUtils工具包
-
- 前言
- 实例
前言
现在基本上很少再会让我们自己去写一些JDBC进行数据的写入查询了。但总有特别的时候你会发现，自己写一个JDBCUtils工具包真香。想怎么用怎么用，以下实例代码来源于师兄前辈的分享，以及博主后期使用后的总结，又 增添了一些。仅供参考。如与网上同行前辈的代码有相似之处，请联系博主备注出处。感谢前行者们对于编程事业的分享和付出！每一个可爱的人都值得尊敬！实例
package cc;
import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class JDBCUtils {
//数据库更新，
/* xumz
* conn 数据库连接
* sql
* obj 任意个参数
* */
public static int update(Connection conn,String sql,Object...obj) {
PreparedStatement ps = null;
int res;
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < obj.length; i++) {
ps.setObject(i+1, obj[i]);
}
res=ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
res=-1;
} finally {
closeAll(conn, null, ps, null);
}
return res;
}
//传入参数变为List数组，这种情况有时候比上面的那个uodate更加好用，因为参数变成动态的了，在程序执行前谁都不知道到底有多少个参数
public static int updateList(Connection conn,String sql,List datalist) {
PreparedStatement ps = null;
int res;
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < datalist.size(); i++) {
ps.setObject(i+1, datalist.get(i));
}
res=ps.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
res=-1;
} finally {
closeAll(conn, null, ps, null);
}
return res;
}
/**
* 简单查询语句
* 返回一个字符串
* @param conn
* @param sql
* @param obj
* @return
*/
public static String queryForString(Connection conn,String sql,Object...obj){
PreparedStatement ps = null;
ResultSet rs = null;
String res =null;
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < obj.length; i++) {
ps.setObject(i+1, obj[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
if(rs.next()){
res= rs.getString(rsmd.getColumnLabel(1));
}
} catch (Exception e) {
e.printStackTrace();
res=null;
} finally {
closeAll(conn, null, ps, rs);
}
return res;
}
/*
* 简单查询语句
* 返回int值
* */
public static Integer queryForInt(Connection conn,String sql,Object...obj){
PreparedStatement ps = null;
ResultSet rs = null;
Integer res =-1;
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < obj.length; i++) {
ps.setObject(i+1, obj[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
if(rs.next()){
res= rs.getInt(rsmd.getColumnLabel(1));
}
} catch (Exception e) {
e.printStackTrace();
res=-1;
} finally {
closeAll(conn, null, ps, rs);
}
return res;
}
/*
* */
public static Integer queryForIntList(Connection conn,String sql,List datalist){
PreparedStatement ps = null;
ResultSet rs = null;
Integer res =-1;
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < datalist.size(); i++) {
ps.setObject(i+1, datalist.get(i));
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
if(rs.next()){
res= rs.getInt(rsmd.getColumnLabel(1));
}
} catch (Exception e) {
e.printStackTrace();
res=-1;
} finally {
closeAll(conn, null, ps, rs);
}
return res;
}
public static List<Map<String,Object>> queryForList(Connection conn,String sql,Object...obj){
PreparedStatement ps = null;
ResultSet rs = null;
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < obj.length; i++) {
ps.setObject(i+1, obj[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Map<String,Object> map = null;
while(rs.next()){
map = new HashMap<String, Object>();
for (int i = 0; i < columnCount; i++) {
String colunmName = rsmd.getColumnLabel(i+1);
Object columnValue = rs.getObject(colunmName);
map.put(colunmName, columnValue);
}
list.add(map);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
closeAll(conn, null, ps, rs);
}
return list;
}
//重载
public static List<Map<String,Object>> queryForList_list(Connection conn, String sql, List datalist){
PreparedStatement ps = null;
ResultSet rs = null;
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < datalist.size(); i++) {
ps.setObject(i+1, datalist.get(i));
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Map<String,Object> map = null;
while(rs.next()){
map = new HashMap<String, Object>();
for (int i = 0; i < columnCount; i++) {
String colunmName = rsmd.getColumnLabel(i+1);
Object columnValue = rs.getObject(colunmName);
map.put(colunmName, columnValue);
}
list.add(map);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
closeAll(conn, null, ps, rs);
}
return list;
}
/*当形参为Object[]数组时，调用该方法必须为一个数组
当形参为Object...objects时，调用就相当灵活了，可以不带参数，可以带一个参数或者多个参数，也可以带数组作为参数*/
public static List<Map<String,Object>> queryForListForKeyLower(Connection conn,String sql,Object...obj){
PreparedStatement ps = null;
ResultSet rs = null;
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
try {
ps = conn.prepareStatement(sql);
for (int i = 0; i < obj.length; i++) {
ps.setObject(i+1, obj[i]);
}
rs = ps.executeQuery();
ResultSetMetaData rsmd = rs.getMetaData();
int columnCount = rsmd.getColumnCount();
Map<String,Object> map = null;
while(rs.next()){
map = new HashMap<String, Object>();
for (int i = 0; i < columnCount; i++) {
String colunmName = rsmd.getColumnLabel(i+1);
Object columnValue = rs.getObject(colunmName);
map.put(colunmName.toLowerCase(), columnValue);
}
list.add(map);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
closeAll(conn, null, ps, rs);
}
return list;
}
//数据库连接方法
public static Connection openConnection(){
Connection con = null;
try{
Class.forName("oracle.jdbc.driver.OracleDriver");
con = DriverManager.getConnection(
"url",
"username",
"password"
);
}catch(SQLException e){
e.printStackTrace();
}catch(ClassNotFoundException e){
e.printStackTrace();
}
return con;
}
//数据库关闭方法
public static void closeAll(Connection con,Statement st,PreparedStatement ps,ResultSet rs) {
try {
if (rs != null) {
rs.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if (st != null) {
st.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if (ps != null) {
ps.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if (con != null) {
con.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
/* 调用方法如：
Connection conn = JDBCUtils.openConnection();
String sql_read = "select * from testa ";
List> list = JDBCUtils.queryForList(conn, sql_read);
*/
}
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