java连接mysql数据库 三 实现增删改查操作
public>public static void main(String[] args){//add(uname, uemail, upwd);//update("李诗诗","lishishi@com","666");//show(); del("王小五");
}
//插入操作
public static int add(String uname,String uemail,String upwd) {
int i=0;
String sql="insert into employee (name,email,pwd) values (?,?,?)";
DBConnection db = new DBConnection();
try {
PreparedStatement preStmt = (PreparedStatement) db.conn.prepareStatement(sql);
preStmt.setString(1, uname);
preStmt.setString(2, uemail);
preStmt.setString(3, upwd);
preStmt.executeUpdate();
//Statement statement = (Statement) db.conn.createStatement();
//statement.executeUpdate(sql);
preStmt.close();
db.close();//关闭连接
} catch (Exception e) {
e.printStackTrace();
}
return i;//返回影响的行数，1为执行成功
}
//查找操作
public static void show(){
String sql ="select * from employee";
DBConnection db = new DBConnection();
System.out.println("-----------------");
System.out.println("姓名" +"\t"+ "邮箱" +"\t"+ "日期");
System.out.println("-----------------");
try {
Statement stmt = (Statement) db.conn.createStatement();
ResultSet rs = (ResultSet) stmt.executeQuery(sql);
while(rs.next()){
String uname = rs.getString("name");
String uemail = rs.getString("email");
String uhiredate = rs.getString("hiredate");
//可以将查找到的值写入类，然后返回相应的对象
//这里 先用输出的端口显示一下
System.out.println(uname +"\t"+ uemail +"\t"+ uhiredate);
}
rs.close();
db.close();//关闭连接
} catch (SQLException e) {
e.printStackTrace();
}
}
//更新操作
public static int update(String uname,String uemail,String upwd) {
int i =0;
String sql="update employee set email=?,pwd=? where name=?";
DBConnection db = new DBConnection();
try {
PreparedStatement preStmt = (PreparedStatement) db.conn.prepareStatement(sql);
preStmt.setString(1, uemail);
preStmt.setString(2, upwd);
preStmt.setString(3, uname);
preStmt.executeUpdate();
preStmt.close();
db.close();//关闭连接
} catch (SQLException e) {
e.printStackTrace();
}
return i;//返回影响的行数，1为执行成功
}
//删除操作
public static int del(String uname) {
int i=0;
String sql="delete from employee where name=?";
DBConnection db = new DBConnection();
try {
PreparedStatement preStmt = (PreparedStatement) db.conn.prepareStatement(sql);
preStmt.setString(1, uname);
preStmt.executeUpdate();
preStmt.close();
db.close();//关闭连接
} catch (SQLException e){
e.printStackTrace();
}
return i;//返回影响的行数，1为执行成功
}
}
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