Java操作Mysql笔记

                  1
                import java.sql.*;
  2import java.util.jar.JarException;
  3  4publicclass DBManager {
  5// 用户名  6private String user = "";
  7// 密码  8private String password = "";
  9// 主机 10private String host = "";
 11// 数据库名字 12private String database = "";
 13/* 14     * 
 15     * private String
 16     * url="jdbc:mysql://"+host+"/"+"useUnicode=true&characterEncoding=GB2312";
 17*/ 18private String url = "";
 19private Connection con = null;
 20    Statement stmt;
 21/** 22     * 
 23     * 根据主机、数据库名称、数据库用户名、数据库用户密码取得连接。
 24     * 
 25     * @param host
 26     *            String
 27     * 
 28     * @param database
 29     *            String
 30     * 
 31     * @param user
 32     *            String
 33     * 
 34     * @param password
 35     *            String
 36*/ 37public DBManager(String host, String database, String user, String password) {
 38this.host = host;
 39this.database = database;
 40this.user = user;
 41this.password = password;
 42// 显示中文 43this.url = "jdbc:mysql://" + host + "/" + database;
 44try {
 45             Class.forName("com.mysql.jdbc.Driver");
 46         } catch (ClassNotFoundException e) {
 47             System.err.println("class not found:" + e.getMessage());
 48        }
 49try {
 50             con = DriverManager.getConnection(this.url, this.user,
 51this.password);
 52// 连接类型为ResultSet.TYPE_SCROLL_INSENSITIVE,
 53// ResultSet.CONCUR_READ_ONLY 54             stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
 55                    ResultSet.CONCUR_READ_ONLY);
 56         } catch (SQLException a) {
 57             System.err.println("sql exception:" + a.getMessage());
 58        }
 59    }
 60/** 61     * 
 62     * 返回取得的连接
 63*/ 64public Connection getCon() {
 65return con;
 66    }
 67/** 68     * 
 69     * 执行一条简单的查询语句
 70     * 
 71     * 返回取得的结果集
 72*/ 73public ResultSet executeQuery(String sql) {
 74         ResultSet rs = null;
 75try {
 76             rs = stmt.executeQuery(sql);
 77         } catch (SQLException e) {
 78            e.printStackTrace();
 79        }
 80return rs;
 81    }
 82/** 83     * 
 84     * 执行一条简单的更新语句
 85     * 
 86     * 执行成功则返回true
 87*/ 88publicboolean executeUpdate(String sql) {
 89boolean v = false;
 90try {
 91             v = stmt.executeUpdate(sql) > 0 ? true : false;
 92         } catch (SQLException e) {
 93            e.printStackTrace();
 94         } finally {
 95return v;
 96        }
 97    }
 98publicstaticvoid main(String[] args) throws java.lang.NullPointerException{
 99        ResultSet rs;
100         DBManager exe = new DBManager("127.0.0.1", "test", "root", "118118");
101102         rs = exe.executeQuery("SELECT * FROM student");
103104try {
105             ResultSetMetaData meta_data = rs.getMetaData();//列名106for (int i_col = 1; i_col <= meta_data.getColumnCount(); i_col++) {
107                 System.out.print(meta_data.getColumnLabel(i_col) + "   ");
108            }
109            System.out.println();
110while (rs.next()) {
111for (int i_col = 1; i_col <= meta_data.getColumnCount(); i_col++) {
112                     System.out.print(rs.getString(i_col) + "  ");
113                }
114                System.out.println();
115            }
116         } catch (Exception e) {
117118        }
119    }
120 }