用java写. 查询所有宠物主人信息。使用JDBC查询数据表master中所有宠物主人信息并输出。 2. 插入两条宠物主人信息并提示插入成功。

好的，以下是使用Java JDBC查询数据表master中所有宠物主人信息并输出的代码：

import java.sql.*;

public class QueryMaster {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/petclinic?useSSL=false&serverTimezone=UTC";
        String username = "root";
        String password = "password";
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        try {
            conn = DriverManager.getConnection(url, username, password);
            stmt = conn.createStatement();
            String sql = "SELECT * FROM master";
            rs = stmt.executeQuery(sql);
            while (rs.next()) {
                int id = rs.getInt("id");
                String firstName = rs.getString("first_name");
                String lastName = rs.getString("last_name");
                String address = rs.getString("address");
                String city = rs.getString("city");
                String telephone = rs.getString("telephone");
                System.out.println("ID: " + id + ", First Name: " + firstName + ", Last Name: " + lastName +
                        ", Address: " + address + ", City: " + city + ", Telephone: " + telephone);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

接下来是插入两条宠物主人信息并提示插入成功的代码：

import java.sql.*;

public class InsertMaster {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/petclinic?useSSL=false&serverTimezone=UTC";
        String username = "root";
        String password = "password";
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            conn = DriverManager.getConnection(url, username, password);
            String sql = "INSERT INTO master (first_name, last_name, address, city, telephone) VALUES (?, ?, ?, ?, ?)";
            pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, "John");
            pstmt.setString(2, "Doe");
            pstmt.setString(3, "123 Main St");
            pstmt.setString(4, "Anytown");
            pstmt.setString(5, "555-555-1212");
            int rowsAffected = pstmt.executeUpdate();
            if (rowsAffected == 1) {
                System.out.println("Insert successful.");
            }
            pstmt.setString(1, "Jane");
            pstmt.setString(2, "Doe");
            pstmt.setString(3, "456 Elm St");
            pstmt.setString(4, "Anytown");
            pstmt.setString(5, "555-555-1213");
            rowsAffected = pstmt.executeUpdate();
            if (rowsAffected == 1) {
                System.out.println("Insert successful.");
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            try {
                if (pstmt != null) {
                    pstmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

这两个代码可以分别运行，前者会输出所有宠物主人的信息，后者会插入两条宠物主人信息并提示插入成功。