java oracle clob

create table TEST_CLOB
(
   ID      INTEGER not null,
   NAME    VARCHAR2(20),
  CONTENT CLOB
)
 alter table TEST_CLOB
   add primary key (ID);

create table TEST_CLOB
(
  ID      INTEGER not null,
  NAME    VARCHAR2(20),
  CONTENT CLOB
)
alter table TEST_CLOB
  add primary key (ID);

 

package com.logcd.common;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
 import java.io.Writer;
 import java.net.HttpURLConnection;
 import java.net.URL;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Statement;

 import org.apache.commons.io.FileUtils;

 import oracle.sql.CLOB;

 public class OracleClob {

     public static void main(String[] args) {

         Integer id = saveClobDataUseSQL("测试", getFileContentAsString(
                 "D:/uploadDir/test.txt", true));

         readClobDataUseSQL(id, new File("D:/uploadDir/test2.txt"));
    }

     /**
     * 保存Clob数据
     *
     * @param name
     *            数据名称
     * @param data
     *            字串数据
     */
     @SuppressWarnings("deprecation")
     public static Integer saveClobDataUseSQL(String name, String data) {
        Connection conn = getConnection();
         Integer id = (int) (Math.random() * 100000);

         StringBuilder sqlBuilder = new StringBuilder();
         try {
             conn.setAutoCommit(false);
            Statement stmt = conn.createStatement();

             sqlBuilder.append("insert into TEST_CLOB(ID, NAME, CONTENT) ");
             sqlBuilder.append("values ( " + id);
             sqlBuilder.append(",'" + name + "'");
             sqlBuilder.append(", empty_clob()) ");// 插入一个空对象empty_clob()

            stmt.executeUpdate(sqlBuilder.toString());
             // 锁定数据行进行更新，注意“for update”语句
             String sqlUpd = "select CONTENT from TEST_CLOB where ID = " + id
                     + " for update";
            ResultSet rs = stmt.executeQuery(sqlUpd);
             if (rs.next()) {
                 // 得到java.sql.Clob对象后强制转换为oracle.sql.CLOB
                 CLOB clob = (CLOB) rs.getClob("CONTENT");
                Writer outStream = clob.setCharacterStream(0L);
                 // data是传入的字符串，定义：String data
                 char[] c = data.toCharArray();
                 outStream.write(c, 0, c.length);

                outStream.flush();
                outStream.close();

                conn.commit();
                stmt.close();
            }

         } catch (Exception e) {
             try {
                conn.rollback();
                 id = null;
             } catch (SQLException e1) {
                e1.printStackTrace();
            }
            e.printStackTrace();
         } finally {
             try {
                conn.close();
             } catch (SQLException e) {
                e.printStackTrace();
            }
        }
         return id;
    }

     /**
     * 读出数据并存成文件
     *
     * @param id
     * @param file
     */
     public static void readClobDataUseSQL(Integer id, File file) {
        Connection conn = getConnection();
         try {
            Statement st = conn.createStatement();
             String sql = "select CONTENT from TEST_CLOB where ID = " + id;
            ResultSet rs = st.executeQuery(sql);

             if (rs.next()) {

                 CLOB clob = (CLOB) rs.getClob("CONTENT");

                String result = convertClobToString(clob);
                System.out.println(result);
                 FileUtils.writeStringToFile(file,result, "utf-8");
            }
         } catch (Exception e) {
            e.printStackTrace();
         } finally {
             try {
                conn.close();
             } catch (SQLException e) {
                e.printStackTrace();
            }
        }

    }

     /**
     * 将CLOB转换成字串
     * @param clob
     * @return
     */
     public static String convertClobToString(CLOB clob) {
         String reString = "";
         try {
             Reader is = clob.getCharacterStream();// 得到流
             BufferedReader br = new BufferedReader(is);
            String s = br.readLine();
             StringBuffer sb = new StringBuffer();
             while (s != null) {
                sb.append(s);
                 sb.append("\n");
                s = br.readLine();
            }
            reString = sb.toString().trim();
         } catch(Exception e) {
            e.printStackTrace();
        }
         return reString;
    }

     /**
     * 取得数据库连接
     *
     * @return
     */
     public static Connection getConnection() {
         String driver = "oracle.jdbc.driver.OracleDriver";
         String url = "jdbc:oracle:thin:@195.2.199.5:1521:orcl";
         Connection conn = null;
         try {
            Class.forName(driver);
             conn = DriverManager.getConnection(url, "testdb", "logcd");
         } catch (ClassNotFoundException e) {
            e.printStackTrace();
         } catch (SQLException ex) {
            ex.printStackTrace();
        }
         return conn;
    }

     /**
     * 读取文件内容
     *
     * @param _url
     * @param isLocal
     * @return
     */
     public static String getFileContentAsString(String _url, boolean isLocal) {
         StringBuilder strb = new StringBuilder();
         try {
             InputStreamReader read = null;
            ;
             if (!isLocal) {
                 URL url = new URL(_url);
                HttpURLConnection connection = (HttpURLConnection) url
                        .openConnection();
                 read = new InputStreamReader(connection.getInputStream());
             } else {
                 File file = new File(_url);
                 read = new InputStreamReader(new FileInputStream(file));
            }
             BufferedReader br = new BufferedReader(read);

             char[] cbuf = new char[1024];
             while (br.read(cbuf) != -1) {
                strb.append(cbuf);
            }
         } catch (Exception e) {
            e.printStackTrace();
        }

         return strb.toString();
    }

}