vpruthi/doc-exports
1
0
Fork 0
forked from docs/doc-exports
Code Pull Requests Activity
doc-exports/docs/dws/dev/dws_04_0100.html
Lu, Huayi e6fa411af0 DWS DEV 830.201 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2024-05-16 07:24:04 +00:00

223 lines
25 KiB
HTML
Raw Blame History

<a name="EN-US_TOPIC_0000001233883375"></a><a name="EN-US_TOPIC_0000001233883375"></a>
<h1 class="topictitle1">Example: Importing and Exporting Data Through Local Files</h1>
<div id="body1527239099917"><p id="EN-US_TOPIC_0000001233883375__a79136ca797284d948a4eeae286022381">When the JAVA language is used for secondary development based on <span id="EN-US_TOPIC_0000001233883375__text7947937">GaussDB(DWS)</span>, you can use the CopyManager interface to export data from the database to a local file or import a local file to the database by streaming. The file can be in CSV or TEXT format.</p>
<p id="EN-US_TOPIC_0000001233883375__en-us_topic_0106303462_p537818945212">The sample program is as follows. Load the <span id="EN-US_TOPIC_0000001233883375__text1927746232">GaussDB(DWS)</span> JDBC driver before running it.</p>
<div class="codecoloring" codetype="Java" id="EN-US_TOPIC_0000001233883375__s143da5b6311d42da9f905c046cd3f2c6"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal"> 1</span>
<span class="normal"> 2</span>
<span class="normal"> 3</span>
<span class="normal"> 4</span>
<span class="normal"> 5</span>
<span class="normal"> 6</span>
<span class="normal"> 7</span>
<span class="normal"> 8</span>
<span class="normal"> 9</span>
<span class="normal"> 10</span>
<span class="normal"> 11</span>
<span class="normal"> 12</span>
<span class="normal"> 13</span>
<span class="normal"> 14</span>
<span class="normal"> 15</span>
<span class="normal"> 16</span>
<span class="normal"> 17</span>
<span class="normal"> 18</span>
<span class="normal"> 19</span>
<span class="normal"> 20</span>
<span class="normal"> 21</span>
<span class="normal"> 22</span>
<span class="normal"> 23</span>
<span class="normal"> 24</span>
<span class="normal"> 25</span>
<span class="normal"> 26</span>
<span class="normal"> 27</span>
<span class="normal"> 28</span>
<span class="normal"> 29</span>
<span class="normal"> 30</span>
<span class="normal"> 31</span>
<span class="normal"> 32</span>
<span class="normal"> 33</span>
<span class="normal"> 34</span>
<span class="normal"> 35</span>
<span class="normal"> 36</span>
<span class="normal"> 37</span>
<span class="normal"> 38</span>
<span class="normal"> 39</span>
<span class="normal"> 40</span>
<span class="normal"> 41</span>
<span class="normal"> 42</span>
<span class="normal"> 43</span>
<span class="normal"> 44</span>
<span class="normal"> 45</span>
<span class="normal"> 46</span>
<span class="normal"> 47</span>
<span class="normal"> 48</span>
<span class="normal"> 49</span>
<span class="normal"> 50</span>
<span class="normal"> 51</span>
<span class="normal"> 52</span>
<span class="normal"> 53</span>
<span class="normal"> 54</span>
<span class="normal"> 55</span>
<span class="normal"> 56</span>
<span class="normal"> 57</span>
<span class="normal"> 58</span>
<span class="normal"> 59</span>
<span class="normal"> 60</span>
<span class="normal"> 61</span>
<span class="normal"> 62</span>
<span class="normal"> 63</span>
<span class="normal"> 64</span>
<span class="normal"> 65</span>
<span class="normal"> 66</span>
<span class="normal"> 67</span>
<span class="normal"> 68</span>
<span class="normal"> 69</span>
<span class="normal"> 70</span>
<span class="normal"> 71</span>
<span class="normal"> 72</span>
<span class="normal"> 73</span>
<span class="normal"> 74</span>
<span class="normal"> 75</span>
<span class="normal"> 76</span>
<span class="normal"> 77</span>
<span class="normal"> 78</span>
<span class="normal"> 79</span>
<span class="normal"> 80</span>
<span class="normal"> 81</span>
<span class="normal"> 82</span>
<span class="normal"> 83</span>
<span class="normal"> 84</span>
<span class="normal"> 85</span>
<span class="normal"> 86</span>
<span class="normal"> 87</span>
<span class="normal"> 88</span>
<span class="normal"> 89</span>
<span class="normal"> 90</span>
<span class="normal"> 91</span>
<span class="normal"> 92</span>
<span class="normal"> 93</span>
<span class="normal"> 94</span>
<span class="normal"> 95</span>
<span class="normal"> 96</span>
<span class="normal"> 97</span>
<span class="normal"> 98</span>
<span class="normal"> 99</span>
<span class="normal">100</span>
<span class="normal">101</span>
<span class="normal">102</span>
<span class="normal">103</span>
<span class="normal">104</span></pre></div></td><td class="code"><div><pre><span></span><span class="c1">//gsjdbc4.jar is used as an example.</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.Connection</span><span class="p">;</span><span class="w"> </span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.DriverManager</span><span class="p">;</span><span class="w"> </span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileInputStream</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.FileOutputStream</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.SQLException</span><span class="p">;</span><span class="w"> </span>
<span class="kn">import</span><span class="w"> </span><span class="nn">org.postgresql.copy.CopyManager</span><span class="p">;</span><span class="w"> </span>
<span class="kn">import</span><span class="w"> </span><span class="nn">org.postgresql.core.BaseConnection</span><span class="p">;</span>
<span class="w"> </span>
<span class="kd">public</span><span class="w"> </span><span class="kd">class</span> <span class="nc">Copy</span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span><span class="w"> </span><span class="n">args</span><span class="p">)</span><span class="w"> </span>
<span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">urls</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">String</span><span class="p">(</span><span class="s">&quot;jdbc:postgresql://10.180.155.74:8000/gaussdb&quot;</span><span class="p">);</span><span class="w"> </span><span class="c1">//URL of the database</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">username</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">String</span><span class="p">(</span><span class="s">&quot;jack&quot;</span><span class="p">);</span><span class="w"> </span><span class="c1">//Username</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">password</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">String</span><span class="p">(</span><span class="s">&quot;********&quot;</span><span class="p">);</span><span class="w"> </span><span class="c1">// Password</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">tablename</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">String</span><span class="p">(</span><span class="s">&quot;migration_table&quot;</span><span class="p">);</span><span class="w"> </span><span class="c1">//Define table information.</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">tablename1</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">String</span><span class="p">(</span><span class="s">&quot;migration_table_1&quot;</span><span class="p">);</span><span class="w"> </span><span class="c1">//Define table information.</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">driver</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;org.postgresql.Driver&quot;</span><span class="p">;</span><span class="w"> </span>
<span class="w"> </span><span class="n">Connection</span><span class="w"> </span><span class="n">conn</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">Class</span><span class="p">.</span><span class="na">forName</span><span class="p">(</span><span class="n">driver</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="n">conn</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">DriverManager</span><span class="p">.</span><span class="na">getConnection</span><span class="p">(</span><span class="n">urls</span><span class="p">,</span><span class="w"> </span><span class="n">username</span><span class="p">,</span><span class="w"> </span><span class="n">password</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">ClassNotFoundException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">(</span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">SQLException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">(</span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="c1">//Export the query result of migration_table to the local file d:/data.txt.</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">copyToFile</span><span class="p">(</span><span class="n">conn</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;d:/data.txt&quot;</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;(SELECT * FROM migration_table)&quot;</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">SQLException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">// TODO Auto-generated catch block</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">// TODO Auto-generated catch block</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="c1">//Import data from the d:/data.txt file to the migration_table_1 table.</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">copyFromFile</span><span class="p">(</span><span class="n">conn</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;d:/data.txt&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">migration_table_1</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">SQLException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">// TODO Auto-generated catch block</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">// TODO Auto-generated catch block</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="c1">//Export the data from the migration_table_1 table to the d:/data1.txt file.</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">copyToFile</span><span class="p">(</span><span class="n">conn</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;d:/data1.txt&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">migration_table_1</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">SQLException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">// TODO Auto-generated catch block</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">// TODO Auto-generated catch block</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">copyFromFile</span><span class="p">(</span><span class="n">Connection</span><span class="w"> </span><span class="n">connection</span><span class="p">,</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">filePath</span><span class="p">,</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">tableName</span><span class="p">)</span><span class="w"> </span>
<span class="w"> </span><span class="kd">throws</span><span class="w"> </span><span class="n">SQLException</span><span class="p">,</span><span class="w"> </span><span class="n">IOException</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="n">FileInputStream</span><span class="w"> </span><span class="n">fileInputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">CopyManager</span><span class="w"> </span><span class="n">copyManager</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">CopyManager</span><span class="p">((</span><span class="n">BaseConnection</span><span class="p">)</span><span class="n">connection</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="n">fileInputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileInputStream</span><span class="p">(</span><span class="n">filePath</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="n">copyManager</span><span class="p">.</span><span class="na">copyIn</span><span class="p">(</span><span class="s">&quot;COPY &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">tableName</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="s">&quot; FROM STDIN&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">fileInputStream</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">finally</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">fileInputStream</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">null</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">fileInputStream</span><span class="p">.</span><span class="na">close</span><span class="p">();</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">copyToFile</span><span class="p">(</span><span class="n">Connection</span><span class="w"> </span><span class="n">connection</span><span class="p">,</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">filePath</span><span class="p">,</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">tableOrQuery</span><span class="p">)</span><span class="w"> </span>
<span class="w"> </span><span class="kd">throws</span><span class="w"> </span><span class="n">SQLException</span><span class="p">,</span><span class="w"> </span><span class="n">IOException</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="n">FileOutputStream</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span><span class="w"> </span>
<span class="w"> </span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">CopyManager</span><span class="w"> </span><span class="n">copyManager</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">CopyManager</span><span class="p">((</span><span class="n">BaseConnection</span><span class="p">)</span><span class="n">connection</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="n">fileOutputStream</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">FileOutputStream</span><span class="p">(</span><span class="n">filePath</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="n">copyManager</span><span class="p">.</span><span class="na">copyOut</span><span class="p">(</span><span class="s">&quot;COPY &quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">tableOrQuery</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="s">&quot; TO STDOUT&quot;</span><span class="p">,</span><span class="w"> </span><span class="n">fileOutputStream</span><span class="p">);</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">finally</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">fileOutputStream</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">null</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">fileOutputStream</span><span class="p">.</span><span class="na">close</span><span class="p">();</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">IOException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span><span class="w"> </span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span>
<span class="p">}</span>
</pre></div></td></tr></table></div>
</div>
</div>
<div>
<div class="familylinks">
<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0088.html">JDBC-Based Development</a></div>
</div>
</div>
View Git Blame Copy Permalink