JDBC 连接数据库实例（MySQL为例）

来源：互联网发布：linux mysql开始连接编辑：程序博客网时间：2024/05/23 19:56

比较常规的利用 JDBC 进行数据库操作的几个例子，写下来以防需要。方法肯定不是最好的，此处只是给出几个基本的代码，具体可以根据需要进行优化或者整合。

并且 jdbc 绝对不止这么一点简单的东西。如果熟悉其中的类和方法，可以达到更好的操作体验。

1.加载驱动

Class.forName("com.mysql.jdbc.Driver");

2.建立连接

String url = "jdbc:mysql://localhost:3306/java?user = root&password = root";
Connection conn = DriverManager.getConnection(url, "root", "root");

3.增删改查

1）查：

public void select() throws SQLException {
try {
Statement stmt = conn.createStatement();
String sql = "SELECT * FROM new_table";
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()) {
System.out.print(rs.getInt(1)+" ");
System.out.print(rs.getString(2)+" ");
System.out.println(rs.getInt(3));
}
} catch (SQLException e) {
System.out.println("__Select Error__");
e.printStackTrace();
}finally {
rs.close();
stmt.close();
}
}

2）删

public void delete(int id) throws SQLException {
try{
Statement stmt = conn.createStatement();
String sql = "DELETE FROM new_table WHERE id =?";
PreparedStatement ps = conn.prepareStatement(sql);
ps.setInt(1,id);
ps.executeUpdate();
} catch (SQLException e) {
System.out.println("__Delete Error__");
e.printStackTrace();
}finally {
ps.close();
stmt.close();
}
}

3)增

public void insert(User user) throws SQLException {
try{
int i = 0;
Statement stmt = conn.createStatement();
sql = "INSERT INTO new_table(id, name, age) value(?,?,?)";
ps = (PreparedStatement)conn.prepareStatement(sql);
ps.setInt(1, user.getId());
ps.setString(2,user.getName());
ps.setInt(3, user.getAge());
i = ps.executeUpdate();
} catch (SQLException e) {
System.out.println("__Insert Error__");
e.printStackTrace();
}finally {
ps.close();
stmt.close();
}
}

4）改

public void update(User user) throws SQLException{
try{
int i= 0;
Statement stmt = conn.createStatement();
String sql = "update new_table set name ='"+user.getName()+"',age = '"+user.getAge()+"' where id = '"+user.getId()+"' ";
PreparedStatement ps = (PreparedStatement)conn.prepareStatement(sql);
i = ps.executeUpdate();
}catch (SQLException e){
System.out.println("__Update Error__");
e.printStackTrace();
}finally {
ps.close();
stmt.close();
}
}

5)带东西的查

public void getById(int id) throws SQLException {
try{
Statement stmt = conn.createStatement();
String sql = "select *from new_table where id = '"+id+"'";
ResultSet rs = stmt.executeQuery(sql);
while (rs.next()){
System.out.print(rs.getInt("id") + " ");
System.out.print(rs.getString("name")+" ");
System.out.println(rs.getInt("age"));
}
}catch (SQLException e){
System.out.println("__Get by Id Error__");
e.printStackTrace();
}finally{
ps.close();
stmt.close();
}
}

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