我想从数据库模式中检索所有表名，并且如果可能的话，获取所有以指定前缀开头的表。
我尝试使用 JDBC connection.getMetaData().getTables()，但它根本不起作用。
Connection jdbcConnection = DriverManager.getConnection("", "", "");
DatabaseMetaData m = jdbcConnection.getMetaData();
ResultSet tables = m.getTables(jdbcConnection.getCatalog(), null, "TAB_%", null);
for (int i = 0; i < tables.getMetaData().getColumnCount(); i++) {
System.out.println("table = " + tables.getMetaData().getTableName(i));
}
有人可以帮我吗？
您需要遍历您的 ResultSet 调用next()。
这是来自java2s.com的示例：
DatabaseMetaData md = conn.getMetaData();
ResultSet rs = md.getTables(null, null, "%", null);
while (rs.next()) {
System.out.println(rs.getString(3));
}
第3列是TABLE_NAME（参见文档DatabaseMetaData::getTables）。
public void getDatabaseMetaData()
{
try {
DatabaseMetaData dbmd = conn.getMetaData();
String[] types = {"TABLE"};
ResultSet rs = dbmd.getTables(null, null, "%", types);
while (rs.next()) {
System.out.println(rs.getString("TABLE_NAME"));
}
}
catch (SQLException e) {
e.printStackTrace();
}
}
在您的示例问题中，在 DatabaseMetaData 的 getTables 函数中传递了表名模式。
一些数据库支持大写标识符，一些支持小写标识符。例如 oracle 以大写形式获取表名，而 postgreSQL 以小写形式获取表名。
DatabaseMetaDeta 提供了一种方法来确定数据库如何存储标识符，可以混合大小写，大写，小写参见：http://docs.oracle.com/javase/7/docs/api/java/sql/DatabaseMetaData.html#storesMixedCaseIdentifiers( )
从下面的示例中，您可以获得所有表格和提供表格名称模式的视图，如果您只想要表格然后从 TYPES 数组中删除“VIEW”。
public class DBUtility {
private static final String[] TYPES = {"TABLE", "VIEW"};
public static void getTableMetadata(Connection jdbcConnection, String tableNamePattern, String schema, String catalog, boolean isQuoted) throws HibernateException {
try {
DatabaseMetaData meta = jdbcConnection.getMetaData();
ResultSet rs = null;
try {
if ( (isQuoted && meta.storesMixedCaseQuotedIdentifiers())) {
rs = meta.getTables(catalog, schema, tableNamePattern, TYPES);
} else if ( (isQuoted && meta.storesUpperCaseQuotedIdentifiers())
|| (!isQuoted && meta.storesUpperCaseIdentifiers() )) {
rs = meta.getTables(
StringHelper.toUpperCase(catalog),
StringHelper.toUpperCase(schema),
StringHelper.toUpperCase(tableNamePattern),
TYPES
);
}
else if ( (isQuoted && meta.storesLowerCaseQuotedIdentifiers())
|| (!isQuoted && meta.storesLowerCaseIdentifiers() )) {
rs = meta.getTables(
StringHelper.toLowerCase( catalog ),
StringHelper.toLowerCase(schema),
StringHelper.toLowerCase(tableNamePattern),
TYPES
);
}
else {
rs = meta.getTables(catalog, schema, tableNamePattern, TYPES);
}
while ( rs.next() ) {
String tableName = rs.getString("TABLE_NAME");
System.out.println("table = " + tableName);
}
}
finally {
if (rs!=null) rs.close();
}
}
catch (SQLException sqlException) {
// TODO
sqlException.printStackTrace();
}
}
public static void main(String[] args) {
Connection jdbcConnection;
try {
jdbcConnection = DriverManager.getConnection("", "", "");
getTableMetadata(jdbcConnection, "tbl%", null, null, false);
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
如果您想使用高级 API，它隐藏了数据库模式元数据周围的大量 JDBC 复杂性，请查看这篇文章： http: //www.devx.com/Java/Article/32443/1954
public static ArrayList<String> getTablesList(Connection conn)
throws SQLException {
ArrayList<String> listofTable = new ArrayList<String>();
DatabaseMetaData md = conn.getMetaData();
ResultSet rs = md.getTables(null, null, "%", null);
while (rs.next()) {
if (rs.getString(4).equalsIgnoreCase("TABLE")) {
listofTable.add(rs.getString(3));
}
}
return listofTable;
}
在较新版本的 MySQL 连接器中，如果未通过目录，则还会列出默认表
DatabaseMetaData dbMeta = con.getMetaData();
//con.getCatalog() returns database name
ResultSet rs = dbMeta.getTables(con.getCatalog(), "", null, new String[]{"TABLE"});
ArrayList<String> tables = new ArrayList<String>();
while(rs.next()){
String tableName = rs.getString("TABLE_NAME");
tables.add(tableName);
}
return tables;
DatabaseMetaData md = conn.getMetaData();
String[] types = {"TABLE"};
ResultSet rs = md.getTables("Your_DB_Name", null, "%", types);
while (rs.next()) {
System.out.println(rs.getString("TABLE_NAME"));
}
@Transactional
@RequestMapping(value = { "/getDatabaseTables" }, method = RequestMethod.GET)
public @ResponseBody String getDatabaseTables() throws Exception{
Connection con = ((SessionImpl) sessionFactory.getCurrentSession()).connection();
DatabaseMetaData md = con.getMetaData();
ResultSet rs = md.getTables(null, null, "%", null);
HashMap<String,List<String>> databaseTables = new HashMap<String,List<String>>();
List<String> tables = new ArrayList<String>();
String db = "";
while (rs.next()) {
tables.add(rs.getString(3));
db = rs.getString(1);
}
List<String> database = new ArrayList<String>();
database.add(db);
databaseTables.put("database", database);
Collections.reverse(tables);
databaseTables.put("tables", tables);
return new ObjectMapper().writeValueAsString(databaseTables);
}
@Transactional
@RequestMapping(value = { "/getTableDetails" }, method = RequestMethod.GET)
public @ResponseBody String getTableDetails(@RequestParam(value="tablename")String tablename) throws Exception{
System.out.println("...tablename......"+tablename);
Connection con = ((SessionImpl) sessionFactory.getCurrentSession()).connection();
Statement st = con.createStatement();
String sql = "select * from "+tablename;
ResultSet rs = st.executeQuery(sql);
ResultSetMetaData metaData = rs.getMetaData();
int rowCount = metaData.getColumnCount();
List<HashMap<String,String>> databaseColumns = new ArrayList<HashMap<String,String>>();
HashMap<String,String> columnDetails = new HashMap<String,String>();
for (int i = 0; i < rowCount; i++) {
columnDetails = new HashMap<String,String>();
Method method = com.mysql.jdbc.ResultSetMetaData.class.getDeclaredMethod("getField", int.class);
method.setAccessible(true);
com.mysql.jdbc.Field field = (com.mysql.jdbc.Field) method.invoke(metaData, i+1);
columnDetails.put("columnName", field.getName());//metaData.getColumnName(i + 1));
columnDetails.put("columnType", metaData.getColumnTypeName(i + 1));
columnDetails.put("columnSize", field.getLength()+"");//metaData.getColumnDisplaySize(i + 1)+"");
columnDetails.put("columnColl", field.getCollation());
columnDetails.put("columnNull", ((metaData.isNullable(i + 1)==0)?"NO":"YES"));
if (field.isPrimaryKey()) {
columnDetails.put("columnKEY", "PRI");
} else if(field.isMultipleKey()) {
columnDetails.put("columnKEY", "MUL");
} else if(field.isUniqueKey()) {
columnDetails.put("columnKEY", "UNI");
} else {
columnDetails.put("columnKEY", "");
}
columnDetails.put("columnAINC", (field.isAutoIncrement()?"AUTO_INC":""));
databaseColumns.add(columnDetails);
}
HashMap<String,List<HashMap<String,String>>> tableColumns = new HashMap<String,List<HashMap<String,String>>>();
Collections.reverse(databaseColumns);
tableColumns.put("columns", databaseColumns);
return new ObjectMapper().writeValueAsString(tableColumns);
}