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：获取数据库连接

1：导入mysql的驱动jar包，mysql-connector-java-5.1.8-bin.jar

2：写代码连接数据库，如下32313133353236313431303231363533e58685e5aeb931333363373736：

1 /**

2 *

3 */

4 package com.hlcui.file;

5

6 import java.sql.Connection;

7 import java.sql.DriverManager;

8 import java.sql.SQLException;

9

10 /**

11 * @author Administrator

12 *

13 */

14 public class DBUtil {

15 // 定义数据库连接参数

16 public static final String DRIVER_CLASS_NAME = "com.mysql.jdbc.Driver";

17 public static final String URL = "jdbc:mysql://localhost:3306/test";

18 public static final String USERNAME = "root";

19 public static final String PASSWORD = "root";

20

21 // 注册数据库驱动

22 static {

23 try {

24 Class.forName(DRIVER_CLASS_NAME);

25 } catch (ClassNotFoundException e) {

26 System.out.println("注册失败！");

27 e.printStackTrace();

28 }

29 }

30

31 // 获取连接

32 public static Connection getConn() throws SQLException {

33 return DriverManager.getConnection(URL, USERNAME, PASSWORD);

34 }

35

36 // 关闭连接

37 public static void closeConn(Connection conn) {

38 if (null != conn) {

39 try {

40 conn.close();

41 } catch (SQLException e) {

42 System.out.println("关闭连接失败！");

43 e.printStackTrace();

44 }

45 }

46 }

47 //测试

48 public static void main(String[] args) throws SQLException {

49 System.out.println(DBUtil.getConn());

50 }

51

52 }

三：封装读取图片的流

1 /**

2 *

3 */

4 package com.hlcui.file;

5

6 import java.io.File;

7 import java.io.FileInputStream;

8 import java.io.FileOutputStream;

9 import java.io.IOException;

10 import java.io.InputStream;

11

12 /**

13 * @author Administrator

14 *

15 */

16 public class ImageUtil {

17

18 // 读取本地图片获取输入流

19 public static FileInputStream readImage(String path) throws IOException {

20 return new FileInputStream(new File(path));

21 }

22

23 // 读取表中图片获取输出流

24 public static void readBin2Image(InputStream in, String targetPath) {

25 File file = new File(targetPath);

26 String path = targetPath.substring(0, targetPath.lastIndexOf("/"));

27 if (!file.exists()) {

28 new File(path).mkdir();

29 }

30 FileOutputStream fos = null;

31 try {

32 fos = new FileOutputStream(file);

33 int len = 0;

34 byte[] buf = new byte[1024];

35 while ((len = in.read(buf)) != -1) {

36 fos.write(buf, 0, len);

37 }

38 fos.flush();

39 } catch (Exception e) {

40 e.printStackTrace();

41 } finally {

42 if (null != fos) {

43 try {

44 fos.close();

45 } catch (IOException e) {

46 e.printStackTrace();

47 }

48 }

49 }

50 }

51 }

四：实现图片(本地、数据库互相传输)

1 /**

2 *

3 */

4 package com.hlcui.file;

5

6 import java.io.FileInputStream;

7 import java.io.InputStream;

8 import java.sql.Connection;

9 import java.sql.PreparedStatement;

10 import java.sql.ResultSet;

11 import java.sql.SQLException;

12

13 /**

14 * @author Administrator 测试写入数据库以及从数据库中读取

15 */

16 public class ImageDemo {

17

18 // 将图片插入数据库

19 public static void readImage2DB() {

20 String path = "D:/1.png";

21 Connection conn = null;

22 PreparedStatement ps = null;

23 FileInputStream in = null;

24 try {

25 in = ImageUtil.readImage(path);

26 conn = DBUtil.getConn();

27 String sql = "insert into photo (id,name,photo)values(?,?,?)";

28 ps = conn.prepareStatement(sql);

29 ps.setInt(1, 1);

30 ps.setString(2, "Tom");

31 ps.setBinaryStream(3, in, in.available());

32 int count = ps.executeUpdate();

33 if (count > 0) {

34 System.out.println("插入成功！");

35 } else {

36 System.out.println("插入失败！");

37 }

38 } catch (Exception e) {

39 e.printStackTrace();

40 } finally {

41 DBUtil.closeConn(conn);

42 if (null != ps) {

43 try {

44 ps.close();

45 } catch (SQLException e) {

46 e.printStackTrace();

47 }

48 }

49 }

50

51 }

52

53 // 读取数据库中图片

54 public static void readDB2Image() {

55 String targetPath = "D:/image/1.png";

56 Connection conn = null;

57 PreparedStatement ps = null;

58 ResultSet rs = null;

59 try {

60 conn = DBUtil.getConn();

61 String sql = "select * from photo where id =?";

62 ps = conn.prepareStatement(sql);

63 ps.setInt(1, 1);

64 rs = ps.executeQuery();

65 while (rs.next()) {

66 InputStream in = rs.getBinaryStream("photo");

67 ImageUtil.readBin2Image(in, targetPath);

68 }

69 } catch (Exception e) {

70 e.printStackTrace();

71 } finally {

72 DBUtil.closeConn(conn);

73 if (rs != null) {

74 try {

75 rs.close();

76 } catch (SQLException e) {

77 e.printStackTrace();

78 }

79 }

80 if (ps != null) {

81 try {

82 ps.close();

83 } catch (SQLException e) {

84 e.printStackTrace();

85 }

86 }

87

88 }

89 }

90 //测试

91 public static void main(String[] args) {

92 //readImage2DB();

93 readDB2Image();

94 }

95 }

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