• 【Java/Oracle】怎样在同构的含有Clob字段的表中迁移数据


    有两个表是这样的:

    create table emp430_1(
        id number(12),
        name nvarchar2(20),
        profile clob,
        primary key(id)
    );
    
    create table emp430_2(
        id number(12),
        name nvarchar2(20),
        profile clob,
        primary key(id)
    );

    可以看出,除了表名,两表一模一样。

    如果用Java程序在两表之间迁移数据,可以这样写:

    package com.hy.lab.clob;
    
    import java.io.Reader;
    import java.sql.*;
    import java.util.ArrayList;
    import java.util.List;
    
    public class ClobTransfer {
        //-- 以下为连接Oracle数据库的四大参数
        private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
        private static final String URL = "jdbc:oracle:thin:@127.0.0.1:1521:orcl";
        private static final String USER = "luna";
        private static final String PSWD = "1234";
    
        public static void main(String[] args) throws Exception{
            Connection conn = null;
            Statement stmt = null;
    
            try{
                Class.forName(DRIVER);
                conn = DriverManager.getConnection(URL, USER, PSWD);
    
                String sql="select id,name,profile from emp430_1";
                stmt = conn.createStatement();
                ResultSet rs = stmt.executeQuery(sql);
    
                List<Emp> emps=new ArrayList<>();
                while (rs.next()) {
                    long id=rs.getInt("id");
                    String name=rs.getString("name");
                    String profile=extractTxtFrom(rs.getClob("profile"));
                    emps.add(new Emp(id,name,profile));
                }
    //--------分割线,以上为从1表取数据,以下为往2表塞数据-------------------------
                conn.setAutoCommit(false);
                PreparedStatement pstmt = null;
                String insertSql="insert into emp430_2(id,name,profile) values(?,?,?)";
                pstmt = conn.prepareStatement(insertSql);
    
                for(Emp emp:emps){
                    pstmt.setLong(1,emp.id);
                    pstmt.setString(2,emp.name);
                    Clob clob=conn.createClob();
                    clob.setString(1,emp.profile);
                    pstmt.setClob(3,clob);
    
                    pstmt.addBatch();
                }
    
                pstmt.executeBatch();
                conn.commit();
    
                System.out.println("传输完成");
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    conn.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    
        private static String extractTxtFrom(Clob clob) throws Exception{
            Reader reader=clob.getCharacterStream();
            char[] arr=new char[1024];
            int length=reader.read(arr);
            StringBuilder sb=new StringBuilder();
            while(length!=-1){
                String part=new String(arr,0,length);
                sb.append(part);
                length=reader.read(arr);
            }
            return sb.toString();
        }
    }

    END

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  • 原文地址:https://www.cnblogs.com/heyang78/p/16209475.html
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