JDBC操作Mysql数据库
JDBC(Java Database Connectivity)
今天简单地操作数据库使用起JDBC竟有些生疏,所以特写一篇博文记录JDBC的基本操作
1.JDBC连接Mysql数据库
先导入Mysql的驱动jar包 之后就可以开始连接了
//把JDBC连接封装在这个方法中
private static Connection getConn() {
//驱动程序类
public static final String DRIVER = "com.mysql.jdbc.Driver";
//连接数据库的地址 需要单独记住 数据库名后面是用于消除警告的
public static final String URL = "jdbc:mysql://localhost:3306/数据库名?useUnicode=true&characterEncoding=utf-8&useSSL=false";
//连接数据库的用户名
public static final String USER = "root";
//连接数据库的密码
public static final String PASS = "";
Connection conn = null;
try {
Class.forName(driver); //classLoader,加载对应驱动
conn = (Connection) DriverManager.getConnection(url, username, password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
2.插入数据操作
private static int insert(Student student) {
Connection conn = getConn();
int i = 0;
String sql = "insert into students (Name,Sex,Age) values(?,?,?)";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement) conn.prepareStatement(sql);
pstmt.setString(1, student.getName());
pstmt.setString(2, student.getSex());
pstmt.setString(3, student.getAge());
i = pstmt.executeUpdate();
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
return i;
}
3.删除数据操作
private static int delete(String name) {
Connection conn = getConn();
int i = 0;
String sql = "delete from students where Name='" + name + "'";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement) conn.prepareStatement(sql);
i = pstmt.executeUpdate();
System.out.println("resutl: " + i);
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
return i;
}
4.修改数据操作
private static int delete(String name) {
Connection conn = getConn();
int i = 0;
String sql = "delete from students where Name='" + name + "'";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement) conn.prepareStatement(sql);
i = pstmt.executeUpdate();
System.out.println("resutl: " + i);
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
return i;
}
5.查询数据操作
private static Integer getAll() {
Connection conn = getConn();
String sql = "select * from students";
PreparedStatement pstmt;
try {
pstmt = (PreparedStatement)conn.prepareStatement(sql);
ResultSet rs = pstmt.executeQuery();
int col = rs.getMetaData().getColumnCount();
System.out.println("============================");
while (rs.next()) {
for (int i = 1; i <= col; i++) {
System.out.print(rs.getString(i) + "\t");
if ((i == 2) && (rs.getString(i).length() < 8)) {
System.out.print("\t");
}
}
System.out.println("");
}
System.out.println("============================");
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}