jdbc基础 (三) 大文本、二进制数据处理

 1 package com.cream.ice.jdbc;
 2 
 3 import java.io.File;
 4 import java.io.FileNotFoundException;
 5 import java.io.FileReader;
 6 import java.io.FileWriter;
 7 import java.io.Reader;
 8 import java.io.Writer;
 9 import java.sql.Connection;
10 import java.sql.PreparedStatement;
11 import java.sql.ResultSet;
12 import java.sql.SQLException;
13 
14 import org.junit.Test;
15 
16 /**
17  * 大文本数据操作
18  * 
19  * 假设数据库中已存在表test: 
20  * create table test(
21  *        id int primary key,
22  *        content longtext
23  * );
24  * 
25  * @author ice
26  *
27  */
28 public class ClobDemo {
29     
30     Connection connection = null;
31     PreparedStatement statement = null;
32     ResultSet resultSet=null;
33     
34     @Test
35     public void add(){
36         try {
37             connection=JdbcUtils.getConnection();
38             statement=connection.prepareStatement("insert into test (id,content) values (?,?)");
39             statement.setInt(1, 1);
40             
41             //大文本要使用流的形式。将d:/test.txt内容添加至该记录的content字段
42             File file = new File("d:/test.txt");
43             Reader reader = new FileReader(file);
44             //不能使用long的参数，因为mysql根本支持不到那么大的数据，所以没有实现
45             statement.setCharacterStream(2, reader, (int)file.length());
46             
47             int i = statement.executeUpdate();
48             if(i>0)
49                 System.out.println("插入成功");
50             
51         } catch (SQLException e) {
52             e.printStackTrace();
53         } catch (FileNotFoundException e) {
54             e.printStackTrace();
55         } finally{
56             JdbcUtils.releaseResources(null, statement, connection);
57         }
58     }
59     
60     @Test
61     public void read(){
62         try {
63             connection = JdbcUtils.getConnection();
64             statement = connection.prepareStatement("select * from test where id=?");
65             statement.setInt(1, 1);
66 
67             //将读取内容保存到E盘上
68             resultSet = statement.executeQuery();
69             while(resultSet.next()){
70                 Reader reader = resultSet.getCharacterStream("content");
71                 Writer writer = new FileWriter("e:/test.txt");
72                 char buffer[] = new char[1024];
73                 int len = -1;
74                 while((len=reader.read(buffer))!=-1){
75                     writer.write(buffer, 0, len);
76                 }
77                 reader.close();
78                 writer.close();
79             }
80         } catch (Exception e) {
81             e.printStackTrace();
82         } finally{
83             JdbcUtils.releaseResources(resultSet, statement, connection);
84         }
85     }
86 }

 1 package com.cream.ice.jdbc;
 2 
 3 import java.io.FileInputStream;
 4 import java.io.FileOutputStream;
 5 import java.io.InputStream;
 6 import java.io.OutputStream;
 7 import java.sql.Connection;
 8 import java.sql.PreparedStatement;
 9 import java.sql.ResultSet;
10 
11 import org.junit.Test;
12 
13 /**
14  * 大二进制数据操作
15  * 
16  * 假设数据库中已存在表test: 
17  * create table test(
18  *        id int primary key,
19  *        content longblob
20  * );
21  * 
22  * @author ice
23  *
24  */
25 public class BlobDemo {
26     Connection connection = null;
27     PreparedStatement statement = null;
28     ResultSet resultSet=null;
29     
30     @Test
31     public void add(){
32         try {
33             connection=JdbcUtils.getConnection();
34             statement=connection.prepareStatement("insert into test (id,content) values (?,?)");
35             statement.setInt(1, 1);
36             
37             InputStream in = new FileInputStream("d:/test.jpg");
38             statement.setBinaryStream(2, in, in.available());
39             
40             int i = statement.executeUpdate();
41             if(i>0)
42                 System.out.println("插入成功");
43             
44         } catch (Exception e) {
45             e.printStackTrace();
46         } finally{
47             JdbcUtils.releaseResources(null, statement, connection);
48         }
49     }
50     
51     @Test
52     public void read(){
53         try {
54             connection = JdbcUtils.getConnection();
55             statement = connection.prepareStatement("select * from test where id=?");
56             statement.setInt(1, 1);
57 
58             //保存到E盘上
59             resultSet = statement.executeQuery();
60             while(resultSet.next()){
61                 InputStream in = resultSet.getBinaryStream("content");
62                 OutputStream out = new FileOutputStream("e:/test.jpg");
63                 byte b[] = new byte[1024];
64                 int len = -1;
65                 while((len=in.read(b))!=-1){
66                     out.write(b, 0, len);
67                 }
68                 out.close();
69                 in.close();
70             }
71         } catch (Exception e) {
72             e.printStackTrace();
73         } finally{
74             JdbcUtils.releaseResources(resultSet, statement, connection);
75         }
76     }
77 }