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java連接數(shù)據(jù)庫增、刪、改、查工具類

數(shù)據(jù)庫操作工具類，因?yàn)楦鲝S家數(shù)據(jù)庫的分頁條件不同，目前支持Mysql、Oracle、Postgresql的分頁查詢
在Postgresql環(huán)境測(cè)試過了，其他數(shù)據(jù)庫未測(cè)試。
sql語句需要使用預(yù)編譯形式的

復(fù)制代碼代碼如下:

package db;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Field;
import java.sql.Connection;
import java.sql.Date;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.sql.Time;
import java.sql.Timestamp;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.naming.NamingException;
import javax.sql.DataSource;

/**
* 數(shù)據(jù)庫查詢工具類
* 使用預(yù)編譯的sql
*
* @author XueLiang
*
*/
public class DBUtil {

private static String driver;

private static DataSource ds = null;

private static String url = "jdbc:postgresql://192.168.56.101/db";
private static String user = "test";
private static String password = "12345678";

static {
  try {
   Class.forName("org.postgresql.Driver");
   //ds = (DataSource)SpringContextUtil.getBean("dataSource");
  } catch (Exception e) {
   e.printStackTrace();
  }
}

/**
* 建立連接
*
* @return con Connection
* @throws Exception
*/
private static Connection getConnection() throws Exception {
  Connection conn = DriverManager.getConnection(url, user, password);
//  Connection conn = ds.getConnection();
  Driver d = DriverManager.getDriver(conn.getMetaData().getURL());
  driver = d.getClass().getName();
  return conn;
}

/**
* 關(guān)閉連接
*
* @param conn
* @param stmt
* @param preStmt
* @param rs
* @throws SQLException
*/
private static void replease(Connection conn, Statement stmt, ResultSet rs) throws SQLException {
  if (rs != null) {
   rs.close();
   rs = null;
  }
  if (stmt != null) {
   stmt.close();
   stmt = null;
  }
  if (conn != null) {
   conn.close();
   conn = null;
  }
}

/**
* 利用正則表達(dá)式,獲得SELECT SQL中的列名
*
* @param sql
* @return
*/
private static List<String> getColumnsFromSelect(String sql) {
  List<String> colNames = new ArrayList<String>();
  // 取出sql中列名部分
  Pattern p = Pattern.compile("(?i)select\\s(.*?)\\sfrom.*");
  Matcher m = p.matcher(sql.trim());
  String[] tempA = null;
  if (m.matches()) {
   tempA = m.group(1).split(",");
  }
  if (tempA == null) {
   return null;
  }
  String p1 = "(\\w+)";
  String p2 = "(?:\\w+\\s(\\w+))";
  String p3 = "(?:\\w+\\sas\\s(\\w+))";
  String p4 = "(?:\\w+\\.(\\w+))";
  String p5 = "(?:\\w+\\.\\w+\\s(\\w+))";
  String p6 = "(?:\\w+\\.\\w+\\sas\\s(\\w+))";
  String p7 = "(?:.+\\s(\\w+))";
  String p8 = "(?:.+\\sas\\s(\\w+))";
  p = Pattern.compile("(?:" + p1 + "||" + p2 + "||" + p3 + "||" + p4
    + "||" + p5 + "||" + p6 + "||" + p7 + "||" + p8 + ")");
  for (String temp : tempA) {
   m = p.matcher(temp.trim());
   if (!m.matches()) {
    continue;
   }
   for (int i = 1; i <= m.groupCount(); i++) {
    if (m.group(i) == null || "".equals(m.group(i))) {
     continue;
    }
    colNames.add(m.group(i));
   }
  }
  return colNames;
}

/**
* 利用正則表達(dá)式,獲得INSERT SQL中的列名
*
* @param sql
* @return
*/
private static List<String> getColumnsFromInsert(String sql) {
  List<String> colNames = new ArrayList<String>();
  // 取出sql中列名部分
  Pattern p = Pattern.compile("(?i)insert\\s+into.*\\((.*)\\)\\s+values.*");
  Matcher m = p.matcher(sql.trim());
  String[] tempA = null;
  if (m.matches()) {
   tempA = m.group(1).split(",");
  }
  if (tempA == null) {
   return null;
  }
  String p1 = "(\\w+)";
  String p2 = "(?:\\w+\\s(\\w+))";
  String p3 = "(?:\\w+\\sas\\s(\\w+))";
  String p4 = "(?:\\w+\\.(\\w+))";
  String p5 = "(?:\\w+\\.\\w+\\s(\\w+))";
  String p6 = "(?:\\w+\\.\\w+\\sas\\s(\\w+))";
  String p7 = "(?:.+\\s(\\w+))";
  String p8 = "(?:.+\\sas\\s(\\w+))";
  p = Pattern.compile("(?:" + p1 + "||" + p2 + "||" + p3 + "||" + p4
    + "||" + p5 + "||" + p6 + "||" + p7 + "||" + p8 + ")");
  for (String temp : tempA) {
   m = p.matcher(temp.trim());
   if (!m.matches()) {
    continue;
   }
   for (int i = 1; i <= m.groupCount(); i++) {
    if (m.group(i) == null || "".equals(m.group(i))) {
     continue;
    }
    colNames.add(m.group(i));
   }
  }
  return colNames;
}

/**
* 利用正則表達(dá)式,獲得UPDATE SQL中的列名, 包括WHERE字句的
*
* @param sql
* @return
*/
private static List<String> getColumnsFromUpdate(String sql) {
  List<String> colNames = new ArrayList<String>();
  // 取出sql中列名部分
  Pattern p = Pattern.compile("(?i)update(?:.*)set(.*)(?:from.*)*where(.*(and)*.*)");
  Matcher m = p.matcher(sql.trim());
  String[] tempA = null;
  if (m.matches()) {
   tempA = m.group(1).split(",");
   if(m.groupCount() > 1){
    String[] tmp = m.group(2).split("and");
    String[] fina = new String[tempA.length + tmp.length];
    System.arraycopy(tempA, 0, fina, 0, tempA.length);
    System.arraycopy(tmp, 0, fina, tempA.length, tmp.length);
    tempA = fina;
   }
  }
  if (tempA == null) {
   return null;
  }
  String p1 = "(?i)(\\w+)(?:\\s*\\=\\s*.*)";
  String p2 = "(?i)(?:\\w+\\.)(\\w+)(?:\\s*\\=\\s*.*)";
  p = Pattern.compile(p1 + "||" + p2);
  for (String temp : tempA) {
   m = p.matcher(temp.trim());
   if (!m.matches()) {
    continue;
   }
   for (int i = 1; i <= m.groupCount(); i++) {
    if (m.group(i) == null || "".equals(m.group(i))) {
     continue;
    }
    colNames.add(m.group(i));
   }
  }
  return colNames;
}

/**
* 為sql添加統(tǒng)計(jì)代碼
*
* @param sql
* @return
*/
private static String addCountSQL(String sql) {
  StringBuffer sb = new StringBuffer();
  sb.append(" select count(*) as dataCount from (");
  sb.append(sql);
  sb.append(") as a");
  return sb.toString();
}

/**
* 為sql添加分頁代碼
*
* @param sql
* @param start
* @param limit
* @return
*/
private static String addPagingSQL(String sql, int start, int limit) {
  StringBuffer sb = new StringBuffer();
  if ("com.microsoft.jdbc.sqlserver.SQLServerDviver".equals(driver)) {//SQLServer 0.7 2000

  } else if ("com.microsoft.sqlserver.jdbc.SQLServerDriver".equals(driver)) {//SQLServer 2005 2008

  } else if ("com.mysql.jdbc.Driver".equals(driver)) {//MySQL
   sb.append(sql);
   sb.append(" LIMIT ");
   sb.append(start);
   sb.append(",");
   sb.append(limit);
  } else if ("oracle.jdbc.driver.OracleDriver".equals(driver)) {//Oracle8/8i/9i/10g數(shù)據(jù)庫（thin模式）
   List<String> list = getColumnsFromSelect(sql);
   sb.append("select ");
   for (String str : list)
    sb.append(str).append(", ");
   sb.deleteCharAt(sb.lastIndexOf(","));
   sb.append(" from (").append(sql).append(") as a");
   sb.append(" where rownum between ").append(start == 0 ? 1 : start).append(" and ").append(limit);
  } else if ("com.ibm.db2.jdbc.app.DB2Driver".equals(driver)) {//DB2

  } else if ("com.sybase.jdbc.SybDriver".equals(driver)) {//Sybase

  } else if ("com.informix.jdbc.IfxDriver".equals(driver)) {//Informix

  } else if ("org.postgresql.Driver".equals(driver)) {//PostgreSQL
   sb.append(sql);
   sb.append(" LIMIT ");
   sb.append(limit);
   sb.append(" OFFSET ");
   sb.append(start);
  }
  return sb.toString();
}
/**
* 將RusultSet對(duì)象實(shí)例化T對(duì)象
*
* @param <T>
* @param t
* @param rs
* @param sql
* @return t
* @throws Exception
*/
private static <T> T instance(Class<T> t, ResultSet rs, String sql) throws Exception{
  List<String> columns = getColumnsFromSelect(sql);
  T obj = t.newInstance();
  for (String col : columns) {
   try{
    Field f = t.getDeclaredField(col);
    f.setAccessible(true);
    Object v = getValue(col, f.getType().getName(), rs);
    f.set(obj, v);
   }catch(NoSuchFieldException e){
    Field[] fields = t.getDeclaredFields();
    for (Field f : fields) {
     Column column = f.getAnnotation(Column.class);
     if(column != null && column.name().equals(col)){
      f.setAccessible(true);
      Object v = getValue(col, f.getType().getName(), rs);
      f.set(obj, v);
     }
    }
   }
  }

  return obj;
}

private static Object getValue(String columnName, String type, ResultSet rs) throws SQLException{
  Object obj = null;
//  System.out.println("name="+f.getName()+", type="+f.getType().getName() );
  if("java.lang.Integer".equals(type) || "int".equals(type)) {
   obj = rs.getInt(columnName);
  }else if("java.lang.Long".equals(type) || "long".equals(type)) {
   obj = rs.getLong(columnName);
  }else if("java.lang.Short".equals(type)||"short".equals(type)) {
   obj = rs.getShort(columnName);
  }else if("java.lang.Float".equals(type)||"float".equals(type)) {
   obj = rs.getFloat(columnName);
  }else if("java.lang.Double".equals(type)||"double".equals(type)) {
   obj = rs.getDouble(columnName);
  }else if("java.lang.Byte".equals(type)||"byte".equals(type)) {
   obj = rs.getByte(columnName);
  }else if("java.lang.Boolean".equals(type)||"boolean".equals(type)) {
   obj = rs.getBoolean(columnName);
  }else if("java.lang.String".equals(type)) {
   obj = rs.getString(columnName);
  }else {
   obj = rs.getObject(columnName);
  }
//  System.out.println("name="+f.getName() +", type="+f.getType().getName()+", value="+(obj == null ? "NULL" : obj.getClass())+",{"+columnName+":"+obj+"}");
  return obj;
}
/**
* 將param中的參數(shù)添加到pstate
*
* @param pstate
* @param columns
* @throws SQLException
*/
private static <T> void setParameters(PreparedStatement pstate, Object... params) throws Exception {
  if (params != null && params.length > 0) {
   for (int i = 0; i < params.length; i++) {
    Object value = params[i];
    int j = i + 1;
    if (value == null)
     pstate.setString(j, "");
    if (value instanceof String)
     pstate.setString(j, (String) value);
    else if (value instanceof Boolean)
     pstate.setBoolean(j, (Boolean) value);
    else if (value instanceof Date)
     pstate.setDate(j, (Date) value);
    else if (value instanceof Double)
     pstate.setDouble(j, (Double) value);
    else if (value instanceof Float)
     pstate.setFloat(j, (Float) value);
    else if (value instanceof Integer)
     pstate.setInt(j, (Integer) value);
    else if (value instanceof Long)
     pstate.setLong(j, (Long) value);
    else if (value instanceof Short)
     pstate.setShort(j, (Short) value);
    else if (value instanceof Time)
     pstate.setTime(j, (Time) value);
    else if (value instanceof Timestamp)
     pstate.setTimestamp(j, (Timestamp) value);
    else
     pstate.setObject(j, value);
   }
  }

}
/**
* 將param中的參數(shù)添加到pstate
*
* @param pstate
* @param columns
* @param t
* @throws SQLException
*/
private static <T> void setParameters(PreparedStatement pstate, List<String> columns, T t) throws Exception {
  if (columns != null && columns.size() > 0) {
   for (int i = 0; i < columns.size(); i++) {
    String attr = columns.get(i);
    Object value = null;
    Class<?> c = t.getClass();
    try{
     Field f = c.getDeclaredField(attr);
     value = f.get(t);
    } catch (NoSuchFieldException e){
     Field[] fields = c.getDeclaredFields();
     for (Field f : fields) {
      Column column = f.getAnnotation(Column.class);
      if(column != null && column.name().equals(attr))
       value = f.get(t);
     }
    }
    int j = i + 1;
    if (value == null)
     pstate.setString(j, "");
    if (value instanceof String)
     pstate.setString(j, (String) value);
    else if (value instanceof Boolean)
     pstate.setBoolean(j, (Boolean) value);
    else if (value instanceof Date)
     pstate.setDate(j, (Date) value);
    else if (value instanceof Double)
     pstate.setDouble(j, (Double) value);
    else if (value instanceof Float)
     pstate.setFloat(j, (Float) value);
    else if (value instanceof Integer)
     pstate.setInt(j, (Integer) value);
    else if (value instanceof Long)
     pstate.setLong(j, (Long) value);
    else if (value instanceof Short)
     pstate.setShort(j, (Short) value);
    else if (value instanceof Time)
     pstate.setTime(j, (Time) value);
    else if (value instanceof Timestamp)
     pstate.setTimestamp(j, (Timestamp) value);
    else
     pstate.setObject(j, value);
   }
  }

}

/**
* 執(zhí)行insert操作
*
* @param sql 預(yù)編譯的sql語句
* @param t sql中的參數(shù)
* @return 執(zhí)行行數(shù)
* @throws Exception
*/
public static <T> int insert(String sql, T t) throws Exception {
  Connection conn = null;
  PreparedStatement pstate = null;
  int updateCount = 0;
  try {
   conn = getConnection();
   List<String> columns = getColumnsFromInsert(sql);
   pstate = conn.prepareStatement(sql);
   setParameters(pstate, columns, t);
   updateCount = pstate.executeUpdate();
  } finally {
   replease(conn, pstate, null);
  }
  return updateCount;
}
/**
* 執(zhí)行insert操作
*
* @param sql 預(yù)編譯的sql語句
* @param param 參數(shù)
* @return 執(zhí)行行數(shù)
* @throws Exception
*/
public static <T> int insert(String sql, Object... param) throws Exception {
  Connection conn = null;
  PreparedStatement pstate = null;
  int updateCount = 0;
  try {
   conn = getConnection();
   pstate = conn.prepareStatement(sql);
   setParameters(pstate, param);
   updateCount = pstate.executeUpdate();
  } finally {
   replease(conn, pstate, null);
  }
  return updateCount;
}
/**
* 執(zhí)行update操作
*
* @param sql 預(yù)編譯的sql語句
* @param t sql中的參數(shù)
* @return 執(zhí)行行數(shù)
* @throws Exception
*/
public static <T> int update(String sql, T t) throws Exception {
  Connection conn = null;
  PreparedStatement pstate = null;
  int updateCount = 0;
  try {
   conn = getConnection();
   List<String> columns = getColumnsFromUpdate(sql);
   pstate = conn.prepareStatement(sql);
   setParameters(pstate, columns, t);
   updateCount = pstate.executeUpdate();
  } finally {
   replease(conn, pstate, null);
  }
  return updateCount;
}
/**
* 執(zhí)行update操作
*
* @param sql
* @param param 參數(shù)
* @return 執(zhí)行行數(shù)
* @throws Exception
*/
public static <T> int update(String sql, Object... param) throws Exception {
  Connection conn = null;
  PreparedStatement pstate = null;
  int updateCount = 0;
  try {
   conn = getConnection();
   pstate = conn.prepareStatement(sql);
   setParameters(pstate, param);
   updateCount = pstate.executeUpdate();
  } finally {
   replease(conn, pstate, null);
  }
  return updateCount;
}
/**
* 查詢復(fù)數(shù)的對(duì)象
*
* @param t 查詢結(jié)果封裝的對(duì)象類型
* @param sql 預(yù)編譯的sql
* @param param 查詢條件
* @return List<T>
* @throws Exception
*/
public static <T> List<T> queryPlural(Class<T> t, String sql, Object... param) throws Exception {
  Connection conn = null;
  PreparedStatement stmt = null;
  ResultSet rs = null;
  List<T> list = new ArrayList<T>();
  try {
   conn = getConnection();
   stmt = conn.prepareStatement(sql);
   setParameters(stmt, param);
   rs = stmt.executeQuery();
   while (rs.next()) {
    list.add(instance(t, rs, sql));
   }
  } finally {
   replease(conn, stmt, rs);
  }
  return list;
}

/**
* 分頁查詢復(fù)數(shù)的對(duì)象
*
* @param t 查詢結(jié)果封裝的對(duì)象類型
* @param start 開始頁
* @param limit 頁大小
* @param sql 預(yù)編譯的sql語句
* @param param 查詢參數(shù)
* @throws Exception
*/
public static <T> List<T> queryPluralForPagging(Class<T> t, int start, int limit, String sql, Object... param) throws Exception {
  Connection conn = null;
  PreparedStatement stmt = null;
  ResultSet rs = null;
  List<T> list = new ArrayList<T>();
  try {
   conn = getConnection();
   //添加分頁代碼
   sql = addPagingSQL(sql, start, limit);
   stmt = conn.prepareStatement(sql);
   setParameters(stmt, param);
   rs = stmt.executeQuery();
   while (rs.next()) {
    list.add(instance(t, rs, sql));
   }
  } finally {
   replease(conn, stmt, rs);
  }
  return list;
}

/**
* 查詢單個(gè)的對(duì)象
*
* @param t 查詢結(jié)果對(duì)象
* @param sql 預(yù)編譯的sql
* @param param 查詢參數(shù)
* @return T
* @throws Exception
*/
public static <T> T querySingular(Class<T> t, String sql, Object... param) throws Exception {
  T obj = null;
  ResultSet rs = null;
  Connection conn = null;
  PreparedStatement pstate = null;
  try {
   conn = getConnection();
   pstate = conn.prepareStatement(sql);
   setParameters(pstate, param);
   rs = pstate.executeQuery();
   if (rs.next()) {
    obj = instance(t, rs, sql);
   }
  } finally {
   replease(conn, pstate, rs);
  }
  return obj;
}

/**
* 查詢數(shù)據(jù)量
*
* @param param 查詢參數(shù)
* @param sql
* @return
* @throws SQLException
* @throws NamingException
*/
public static int queryDataCount(String sql, Object... param)
   throws Exception {
  int dataCount = 0;
  Connection conn = null;
  PreparedStatement pstate = null;
  ResultSet rs = null;
  try {
   conn = getConnection();
   sql = addCountSQL(sql);
   pstate = conn.prepareStatement(sql);
   setParameters(pstate, param);
   rs = pstate.executeQuery();
   if (rs.next()) {
    dataCount = rs.getInt("dataCount");
   }
  } finally {
   replease(conn, pstate, rs);
  }
  return dataCount;
}

/**
* 屬性字段的注釋，用于標(biāo)記該屬性對(duì)應(yīng)的數(shù)據(jù)庫字段
* 例如：
* @Column(name="user_name");
* String userName;
* 表示userName這個(gè)屬性對(duì)應(yīng)的數(shù)據(jù)庫字段是user_name
*
* 如果屬性和數(shù)據(jù)庫字段完全一致，則不必標(biāo)注
* @author xueliang
*/
@Target({ ElementType.FIELD })
@Retention(RetentionPolicy.RUNTIME)
public @interface Column{
String name() default "";
}

}