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写了一个简单的工具类，获取数据库的表、表中字段、字段类型、字段注释等信息。代码如下：
package com.lnjecit.generator.util;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.sql.*;
import java.util.ArrayList;
import java.util.List;
public class DatabaseUtil {
private final static Logger LOGGER = LoggerFactory.getLogger(DatabaseUtil.class);
private static final String DRIVER = "com.mysql.jdbc.Driver";
private static final String URL = "jdbc:mysql://localhost:3306/javaweb?useUnicode=true&characterEncoding=utf8&serverTimezone=Asia/Shanghai";
private static final String USERNAME = "root";
private static final String PASSWORD = "mysql";
private static final String SQL = "SELECT * FROM ";// 数据库操作
static {
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e) {
LOGGER.error("can not load jdbc driver", e);
}
}
/**
* 获取数据库连接
*
* @return
*/
public static Connection getConnection() {
Connection conn = null;
try {
conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
} catch (SQLException e) {
LOGGER.error("get connection failure", e);
}
return conn;
}
/**
* 关闭数据库连接
* @param conn
*/
public static void closeConnection(Connection conn) {
if(conn != null) {
try {
conn.close();
} catch (SQLException e) {
LOGGER.error("close connection failure", e);
}
}
}
/**
* 获取数据库下的所有表名
*/
public static List getTableNames() {
List tableNames = new ArrayList();
Connection conn = getConnection();
ResultSet rs = null;
try {
//获取数据库的元数据
DatabaseMetaData db = conn.getMetaData();
System.out.println("conn.getCatalog() = " + conn.getCatalog());
//从元数据中获取到所有的表名
rs = db.getTables(conn.getCatalog(), null, null, new String[] { "TABLE" });
while(rs.next()) {
String tableName = (String) rs.getObject("TABLE_NAME");
System.out.println("tableName:" + tableName);
tableNames.add(rs.getString(3));
}
} catch (SQLException e) {
LOGGER.error("getTableNames failure", e);
} finally {
try {
rs.close();
closeConnection(conn);
} catch (SQLException e) {
LOGGER.error("close ResultSet failure", e);
}
}
return tableNames;
}
/**
* 获取表中所有字段名称
* @param tableName 表名
* @return
*/
public static List getColumnNames(String tableName) {
List columnNames = new ArrayList();
//与数据库的连接
Connection conn = getConnection();
PreparedStatement pStemt = null;
String tableSql = SQL + tableName;
try {
pStemt = conn.prepareStatement(tableSql);
//结果集元数据
ResultSetMetaData rsmd = pStemt.getMetaData();
//表列数
int size = rsmd.getColumnCount();
for (int i = 0; i
LOGGER.error("getColumnNames failure", e);
} finally {
if (pStemt != null) {
try {
pStemt.close();
closeConnection(conn);
} catch (SQLException e) {
LOGGER.error("getColumnNames close pstem and connection failure", e);
}
}
}
return columnNames;
}
/**
* 获取表中所有字段类型
* @param tableName
* @return
*/
public static List getColumnTypes(String tableName) {
List columnTypes = new ArrayList();
//与数据库的连接
Connection conn = getConnection();
PreparedStatement pStemt = null;
String tableSql = SQL + tableName;
try {
pStemt = conn.prepareStatement(tableSql);
//结果集元数据
ResultSetMetaData rsmd = pStemt.getMetaData();
//表列数
int size = rsmd.getColumnCount();
for (int i = 0; i
LOGGER.error("getColumnTypes failure", e);
} finally {
if (pStemt != null) {
try {
pStemt.close();
closeConnection(conn);
} catch (SQLException e) {
LOGGER.error("getColumnTypes close pstem and connection failure", e);
}
}
}
return columnTypes;
}
/**
* 获取表中字段的所有注释
* @param tableName
* @return
*/
public static List getColumnComments(String tableName) {
List columnTypes = new ArrayList();
//与数据库的连接
Connection conn = getConnection();
PreparedStatement pStemt = null;
String tableSql = SQL + tableName;
List columnComments = new ArrayList();//列名注释集合
ResultSet rs = null;
try {
pStemt = conn.prepareStatement(tableSql);
rs = pStemt.executeQuery("show full columns from " + tableName);
while (rs.next()) {
columnComments.add(rs.getString("Comment"));
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (rs != null) {
try {
rs.close();
closeConnection(conn);
} catch (SQLException e) {
LOGGER.error("getColumnComments close ResultSet and connection failure", e);
}
}
}
return columnComments;
}
public static void main(String[] args) {
List tableNames = getTableNames();
System.out.println("tableNames:" + tableNames);
for (String tableName : tableNames) {
System.out.println("ColumnNames:" + getColumnNames(tableName));
System.out.println("ColumnTypes:" + getColumnTypes(tableName));
System.out.println("ColumnComments:" + getColumnComments(tableName));
}
}
}
运行代码之前，先将数据库配置进行修改，再运行代码就可以获取数据库表的详细结构了。
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