mysql数据库：
public boolean insertFrom(Person per){
boolean flag = false;
Connection conn = null;
conn = JdbcCon.jdbcConMysql();
PreparedStatement ps = null;
String sql = "insert into person(name,birthday,sex) values(?,?,?)";
try {
ps = conn.prepareStatement(sql);
ps.setString(1, per.getName());
ps.setDate(2, per.getBirthday());
ps.setInt(3, per.getSex());
int i = ps.executeUpdate();
if(i != 0){
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcCon.closeAll(null, ps, conn);
}
return flag;
}
public boolean updateFrom(int id,int sex,String name){
boolean flag = false;
Connection conn = null;
conn = JdbcCon.jdbcConMysql();
String sql = "update person set sex=?,name=? where id=?";
PreparedStatement ps = null;
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, sex);
ps.setString(2, name);
ps.setInt(3, id);
int i = ps.executeUpdate();
if(i != 0){
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcCon.closeAll(null, ps, conn);
}
return flag;
}
public boolean deleteFrom(int id){
boolean flag = false;
Connection conn = null;
conn = JdbcCon.jdbcConMysql();
PreparedStatement ps = null;
String sql= "delete from person where id=?";
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, id);
int i = ps.executeUpdate();
if(i != 0){
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcCon.closeAll(null, ps, conn);
}
return flag;
}
public Person selectFrom(String name,int id){
Person per = null;
Connection conn = null;
conn = JdbcCon.jdbcConMysql();
String sql = "select * from person where id=? and name=?";
PreparedStatement ps = null;
ResultSet rs = null;
try {
ps = conn.prepareStatement(sql);
ps.setInt(1, id);
ps.setString(2, name);
rs = ps.executeQuery();
while(rs.next()){
per = new Person();
per.setBirthday(rs.getDate("birthday"));
per.setId(rs.getInt("id"));
per.setName(rs.getString("name"));
per.setSex(rs.getInt("sex"));
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
JdbcCon.closeAll(rs, ps, conn);
}
return per;
}
Oracle数据库：
public boolean insertStu(Stu stu){
boolean flag = false;
Connection conn = null;
Statement st = null;
StringBuilder sql = new StringBuilder();
sql.append("insert into stu(id,stu_num,stu_name) values(seq_stu_id.nextval,'");
sql.append(stu.getStu_num());
sql.append("','");
sql.append(stu.getStu_name());
sql.append("')");
conn = DBConn.getConn();
try {
st = conn.createStatement();
int i = st.executeUpdate(sql.toString());
if(i != 0){
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(null, st, conn);
}
return flag;
}
public static void main(String[] args) {
Stu stu = new Stu();
stu.setStu_name("aaabbbbccc");
stu.setStu_num("6543211");
StuDao dao = new StuDao();
System.out.println(dao.insertStu(stu));
}
封装
public class JdbcCon {
private static String jdbcDriver = "";
private static String jdbcUrl = "";
private static String jdbcUser = "";
private static String jdbcpasswd = "";
static {
InputStream is = null;
try {
is = JdbcCon.class.getClassLoader().getResourceAsStream("database.properties");
Properties p = new Properties();
p.load(is);
jdbcDriver = p.getProperty("jdbcDriver");
jdbcUrl = p.getProperty("jdbcUrl");
jdbcUser = p.getProperty("jdbcUser");
jdbcpasswd = p.getProperty("jdbcpasswd");
// System.out.println(p.getProperty("jdbcDriver"));
// System.out.println(p.getProperty("jdbcUrl"));
// System.out.println(p.getProperty("jdbcUser"));
// System.out.println(p.getProperty("jdbcpasswd"));
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
if(is != null){
is.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static Connection jdbcConMysql(){
Connection conn = null;
try {
Class.forName(jdbcDriver);
conn = DriverManager.getConnection(jdbcUrl, jdbcUser, jdbcpasswd);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
public static void closeAll(ResultSet rs,Statement st,Connection conn){
try {
if(rs != null){
rs.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(st != null){
st.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(conn != null){
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
public static void closeAll(ResultSet rs,PreparedStatement ps,Connection conn){
try {
if(rs != null){
rs.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(ps != null){
ps.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
try {
if(conn != null){
conn.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}
properties写在src目录下，JdbcCon.class.getClassLoader().getResourceAsStream()默认在src目录下找properties文件
mysql数据库链接参数：
#以下是mysql数据库的配置信息
#jdbcDriver=com.mysql.jdbc.Driver
#jdbcUrl=jdbc:mysql://localhost:3306/change
#jdbcUser=root
#jdbcPasswd=476645144
oracle数据库链接参数：
#以下是oracle数据库的配置信息
#jdbcDriver=oracle.jdbc.driver.OracleDriver
#jdbcUrl=jdbc:oracle:thin:@localhost:1521:ORCL
#jdbcUser=scott
#jdbcPasswd=tiger
批处理四种方式比较。
public boolean regUser(User user){
boolean flag = false;
Connection conn = null;
PreparedStatement ps = null;
String sql = "insert into user(email,passwd,nickname,sex) values(?,?,?,?)";
conn = DBConn.getConn();
try {
ps = conn.prepareStatement(sql);
ps.setString(1, user.getEmail());
ps.setString(2, user.getPasswd());
ps.setString(3, user.getNickname());
ps.setInt(4, user.getSex());
int i = ps.executeUpdate();
if(i != 0){
flag = true;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(null, ps, conn);
}
return flag;
}
public boolean insertUsersByCom(List<User> list){
boolean flag = true;
Connection conn = null;
Statement st = null;
conn = DBConn.getConn();
try {
st = conn.createStatement();
for (User user : list) {
StringBuilder sql = new StringBuilder();
sql.append("insert into user(email,passwd,sex,nickname) values('");
sql.append(user.getEmail());
sql.append("','");
sql.append(user.getPasswd());
sql.append("',");
sql.append(user.getSex());
sql.append(",'");
sql.append(user.getNickname());
sql.append("')");
System.out.println(sql.toString());
int i = st.executeUpdate(sql.toString());
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(null, st, conn);
}
return flag;
}
public boolean insertUsersByPre(List<User> list){
boolean flag = true;
Connection conn = null;
PreparedStatement ps = null;
String sql = "insert into user(email,passwd,nickname,sex) values(?,?,?,?)";
conn = DBConn.getConn();
try {
ps = conn.prepareStatement(sql);
for (User user : list) {
ps.setString(1, user.getEmail());
ps.setString(2, user.getPasswd());
ps.setString(3, user.getNickname());
ps.setInt(4, user.getSex());
int i = ps.executeUpdate();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(null, ps, conn);
}
return flag;
}
public boolean insertUsersByStandard(List<User> list){
boolean flag = true;
Connection conn = null;
PreparedStatement ps = null;
String sql = "insert into user(email,passwd,nickname,sex) values(?,?,?,?)";
conn = DBConn.getConn();
try {
ps = conn.prepareStatement(sql);
for (User user : list) {
ps.setString(1, user.getEmail());
ps.setString(2, user.getPasswd());
ps.setString(3, user.getNickname());
ps.setInt(4, user.getSex());
//真正的批处理 在这里并不执行 而是将当前的这条命令 加入到批处理的队列中
ps.addBatch();
}
ps.executeBatch();//执行批处理命令
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(null, ps, conn);
}
return flag;
}
public static void main(String[] args) {
List<User> list = new ArrayList<User>();
for (int i = 0; i < 10; i++) {
User user = new User();
user.setEmail("xiaowang" + i + "@126.com");
user.setNickname("wang" + i);
user.setPasswd("8787878");
user.setSex(0);
list.add(user);
}
// UserDao dao = new UserDao();
//第一种 调用regUser(User user)插入10条记录 获取连接和statement各10次 sql语句编译和执行各10次 关闭10次
// for (User user : list) {
// dao.regUser(user);
// }
//第二种 调用insertUsersByCom(List<User> list) 获取连接和statement各一次 sql语句编译和执行各10次 关闭一次
// dao.insertUsersByCom(list);
//第三种 调用insertUsersByPre(List<User> list) 获取连接和statement各一次 sql语句编译一次 执行10次 关闭一次
// dao.insertUsersByPre(list);
//第四种 调用insertUsersByStandard(List<User> list) 获取连接和statment sql语句编译执行 关闭都仅有一次
UserDao.getInstance().insertUsersByStandard(list);
}
数据库的事务，把conn的自动提交模式改为手动提交，当两条sql语句都成功完成时才提交，否则都回滚。
public boolean transferMoney(String from,String to,double money){
boolean flag = false;
String sql1 = "update bank set money=money-? where bankcard=?";
String sql2 = "update bank set money=money+? where bankcard=?";
Connection conn = null;
PreparedStatement ps = null;-
conn = DBConn.getConn();
try {
conn.setAutoCommit(false);//将自动提交模式改为手动提交(autoCommit - 为 true 表示启用自动提交模式；为 false 表示禁用自动提交模式)
ps = conn.prepareStatement(sql1);
ps.setDouble(1, money);
ps.setString(2, from);
int i1 = ps.executeUpdate();
ps = conn.prepareStatement(sql2);
ps.setDouble(1, money);
ps.setString(2, to);
int i2 = ps.executeUpdate();
if(i1 != 0 && i2 != 0){
flag = true;
conn.commit();//手动提交
}else{
conn.rollback();//回滚
}
} catch (SQLException e) {
e.printStackTrace();
try {
conn.rollback();//发生一场也回滚
} catch (SQLException e1) {
e1.printStackTrace();
}
} finally {
DBConn.closeAll(null, ps, conn);
}
return flag;
}
单例模式 只能new一次，节省资源省开销，通常在dao包中使用
private NewsDao(){
}
private static NewsDao dao = null;
public static NewsDao getInstance(){
if(dao == null){
dao = new NewsDao();
}
return dao;
}
/**
* @param value:指的是用户输入的邮箱或者是昵称的信息
* @param type :指的是该次验证的字段是哪个字段 如果0代表验证的邮箱 1代表验证的昵称
* @return
* @function:验证用户输入的email或者是昵称是否被占用
*/
public static boolean isOnly(String value,int type){
boolean flag = true;
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
StringBuilder sql = new StringBuilder();
sql.append("select id from user where ");
sql.append(type==0?" email=? ":" nickname=?");
System.out.println(sql.toString());
conn = DBConn.getConn();
try {
ps = conn.prepareStatement(sql.toString());
ps.setString(1, value);
rs = ps.executeQuery();
while (rs.next()) {
flag = false;
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(rs, ps, conn);
}
return flag;
}
/**
* @return
* @function:分页查询最新注册用户的信息
*/
public List<User> getUsersByPag(int startRow,int size){
List<User> list = new ArrayList<User>();
Connection conn = null;
PreparedStatement ps = null;
ResultSet rs = null;
String sql = "select * from user order by id desc limit ?,?";
User user = null;
conn = DBConn.getConn();
try {
ps = conn.prepareStatement(sql);
rs = ps.executeQuery();
while (rs.next()) {
user = new User();
user.setEmail(rs.getString("email"));
user.setAddtime(rs.getDate("addtime"));
user.setId(rs.getInt("id"));
user.setNickname(rs.getString("nickname"));
user.setPasswd(rs.getString("passwd"));
user.setSex(rs.getInt("sex"));
list.add(user);
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
DBConn.closeAll(rs, ps, conn);
}
return list;
}