JDBC使用工具类
连接池使用DBCP，代码如下：
工具类JDBCUtils.java
import org.apache.commons.dbcp.BasicDataSource;
import org.apache.commons.dbcp.BasicDataSourceFactory;
import java.sql.SQLException;
import java.sql.Connection;
import java.util.Properties;
public class ConnectionSource {
private static BasicDataSource dataSource = null;
private final static String connUrl1 = "jdbc:mysql://localhost:3306/directory?useUnicode=true&characterEncoding=UTF-8";
private final static String connUrl2 = "";
private static String connUrl = "";
private static boolean connBool = false;
private final static String userName = "root";
private final static String password = "root";
public static void init(String connUrl) {
if (dataSource != null) {
try {
dataSource.close();
} catch (Exception e) {
e.printStackTrace();
}
dataSource = null;
}
try {
Properties p = new Properties();
p.setProperty("driverClassName", "com.mysql.jdbc.Driver");
p.setProperty("url", connUrl);
p.setProperty("username", userName);
p.setProperty("password", password);
// 初始化连接
p.setProperty("initialSize", "20");
// 最大连接数量
p.setProperty("maxActive", "200");
// 最大空闲连接
p.setProperty("maxIdle", "20");
// maxWait的时间不要设得太长
p.setProperty("maxWait", "1000");
// 是否自动回收超时连接
p.setProperty("removeAbandoned", "true");
// 超时时间(以秒数为单位)
p.setProperty("removeAbandonedTimeout", "120");
p.setProperty("testOnBorrow", "true");
// 是否在自动回收超时连接的时候打印连接的超时错误
p.setProperty("logAbandoned", "true");
dataSource = (BasicDataSource) BasicDataSourceFactory.createDataSource(p);
} catch (Exception e) {
e.printStackTrace();
}
}
public static synchronized Connection getConn() throws SQLException {
if (dataSource == null) {
init(connUrl);
}
Connection conn = null;
if (dataSource != null) {
conn = dataSource.getConnection();
}
return conn;
}
public static synchronized Connection getConnection() {
if (!connBool) {
connUrl = connUrl1;
} else {
connUrl = connUrl2;
}
Connection conn = null;
try {
conn = getConn();
} catch (SQLException e) {
}
if (conn == null) {
connBool = true;
dataSource = null;
connUrl = connUrl2;
try {
conn = getConn();
} catch (SQLException e) {
e.printStackTrace();
}
}
return conn;
}
public static void main(String[] args) {
ConnectionSource.getConnection();
}
}
工具类JDBCUtils.java
import java.sql.Clob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
/**
* 数据库操作工具类
*
* @author ZZJ
*/
public class JDBCUtils {
/**
* 执行查询
*
* @param sql
* @param pams like aa,bb,cc
* @return
*/
public static List<Map<String, Object>> getObjects(String sql, String pams) {
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>(0);
Connection conn = null;
String[] ps = pams.split(",");
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
conn = ConnectionSource.getConnection();
pstmt = conn.prepareStatement(sql);
rs = pstmt.executeQuery();
while (rs.next()) {
Map<String, Object> map = new LinkedHashMap<String, Object>(0);
for (int i = 0; i < ps.length; i++) {
if (rs.getObject(ps[i]) instanceof Clob) {
map.put(ps[i], rs.getString(ps[i]));
} else {
map.put(ps[i], rs.getObject(ps[i]));
}
}
list.add(map);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
rs.close();
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return list;
}
/**
* 查询数量
*
* @param sql like select count(id) as c from table
* @return
*/
public static int getCount(String sql) {
List<Map<String, Object>> list = getObjects(sql, "c");
if (list.size() > 0) {
Map<String, Object> m = list.get(0);
return ((Long) m.get("c")).intValue();
}
return 0;
}
/**
* 查询数量
*
* @param table
* @return
*/
public static int getCountByTable(String table) {
String sql = "select count(id) as c from " + table;
List<Map<String, Object>> list = getObjects(sql, "c");
if (list.size() > 0) {
Map<String, Object> m = list.get(0);
return ((Long) m.get("c")).intValue();
}
return 0;
}
/**
*
* @param table
* @param id
* @return
*/
public synchronized static boolean excuteDelete(String table, Integer id) {
String sql = "delete from " + table + " where id=" + id;
Connection conn = null;
PreparedStatement pstmt = null;
try {
conn = ConnectionSource.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.execute();
} catch (Exception e) {
e.printStackTrace();
return false;
} finally {
try {
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return true;
}
/**
* 执行更新语句
*
* @param sql
* @return
*/
public synchronized static boolean excuteUpdate(String sql) {
Connection conn = null;
PreparedStatement pstmt = null;
try {
conn = ConnectionSource.getConnection();
pstmt = conn.prepareStatement(sql);
pstmt.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
return false;
} finally {
try {
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return true;
}
/**
* 执行更新语句
*
* @param table 表名
* @param map 数据对
* @param id 数据ID
* @return
*/
public synchronized static boolean excuteUpdate(String table, Map<String, Object> map, Integer id) {
Set<Map.Entry<String, Object>> sets = map.entrySet();
String fields = "";
Iterator<Map.Entry<String, Object>> iterator = sets.iterator();
while (iterator.hasNext()) {
Map.Entry<String, Object> entry = iterator.next();
fields += entry.getKey() + "=?,";
}
if (fields.endsWith(",")) {
fields = fields.substring(0, fields.length() - 1);
}
String sql = "update " + table + " set " + fields + " where id=" + id;
PreparedStatement pstmt = null;
Connection conn = null;
try {
conn = ConnectionSource.getConnection();
pstmt = conn.prepareStatement(sql);
iterator = sets.iterator();
int index = 1;
while (iterator.hasNext()) {
Map.Entry<String, Object> entry = iterator.next();
pstmt.setObject(index, entry.getValue());
index++;
}
pstmt.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return true;
}
/**
* 执行插入数据操作，返回该条的数据的ID
*
* @param table
* @param seq
* @param map
* @return
* @throws SQLException
*/
public static int excuteInsert(String table, Map<String, Object> map) throws SQLException {
Set<Map.Entry<String, Object>> sets = map.entrySet();
String fields = "";
String values = "";
Iterator<Map.Entry<String, Object>> iterator = sets.iterator();
while (iterator.hasNext()) {
Map.Entry<String, Object> entry = iterator.next();
fields += entry.getKey() + ",";
values += "?,";
}
if (fields.endsWith(",")) {
fields = fields.substring(0, fields.length() - 1);
values = values.substring(0, values.length() - 1);
}
StringBuffer sb = new StringBuffer(0);
sb.append("insert into " + table + "(");
sb.append(fields + ")");
sb.append(" values(");
sb.append(values);
sb.append(")");
int id = 0;
PreparedStatement pstmt = null;
ResultSet rs = null;
Connection conn = null;
try {
conn = ConnectionSource.getConnection();
pstmt = conn.prepareStatement(sb.toString(), new String[] { "id" });
iterator = sets.iterator();
int index = 1;
while (iterator.hasNext()) {
Map.Entry<String, Object> entry = iterator.next();
pstmt.setObject(index, entry.getValue());
index++;
}
pstmt.execute();
rs = pstmt.getGeneratedKeys();
while (rs.next()) {
id = rs.getInt(1);
}
} catch (Exception e) {
e.printStackTrace();
if (null != conn) {
conn.rollback();
}
} finally {
try {
rs.close();
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return id;
}
}