小程序---根据数据库反向生成java文件

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

/**
* @author weiwei.Wang
* @date 2016年7月14日
* @todo TODO 根据DB name获取数据库中的table，从而生成java文件
*
*/
public class CreateBean {

private String[] colnames; // 列名数组

private String[] colTypes; // 列名类型数组

private int[] colSizes; // 列名大小数组

private boolean f_util = false; // 是否需要导入包java.util.*

private boolean f_sql = false; // 是否需要导入包java.sql.*

private String url = "jdbc:mysql://127.0.0.1:3306/enrichmind";
private String user = "root";
private String pwd = "";

/**
* 获取数据库连接
*
* @return
*/
public Connection getConnection() {
Connection conn = null;
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(url, user, pwd);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}

/**
* 根据数据库名生成bean java文件
*
* @param path
* @throws Exception
*/
public void createBeanMethod(String DBName, String javaFileSavePath)
throws Exception {

// myDB为数据库名
List<String> tableList = getTableNameByDBname(DBName);
for (int j = 0; j < tableList.size(); j++) {
Connection conn = getConnection(); // 得到数据库连接
String tableName = tableList.get(j);
String strsql = "select * from " + tableName;
PreparedStatement pstmt = null;
ResultSetMetaData rsmd = null;
try {
pstmt = conn.prepareStatement(strsql);
rsmd = pstmt.getMetaData();
int size = rsmd.getColumnCount(); // 共有多少列
colnames = new String[size];
colTypes = new String[size];
colSizes = new int[size];
for (int i = 0; i < rsmd.getColumnCount(); i++) {
colnames[i] = rsmd.getColumnName(i + 1);
colTypes[i] = rsmd.getColumnTypeName(i + 1);
if (colTypes[i].equalsIgnoreCase("datetime")) {
f_util = true;
}
if (colTypes[i].equalsIgnoreCase("image")
|| colTypes[i].equalsIgnoreCase("text")) {
f_sql = true;
}
colSizes[i] = rsmd.getColumnDisplaySize(i + 1);
}
String content = parse(colnames, colTypes, colSizes,
javaFileSavePath, tableName);

try {
FileWriter fw = new FileWriter(initcap(tableName) + ".java");
PrintWriter pw = new PrintWriter(fw);
pw.println(content);
pw.flush();
pw.close();
} catch (IOException e) {
e.printStackTrace();
}
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}

}

/**
* 根据数据库名获取所有table
*
* @param DBname
* @return
*/
public List<String> getTableNameByDBname(String DBname) {
List<String> list = new ArrayList<String>();
try {
Connection conn = getConnection();
DatabaseMetaData dmd = (DatabaseMetaData) conn.getMetaData();
ResultSet rs = dmd.getTables(null, null, "%", null);
while (rs.next()) {
// System.err.println("======"+ rs.getString("TABLE_NAME"));
list.add(rs.getString("TABLE_NAME"));
}
} catch (SQLException e) {
e.printStackTrace();
}
return list;
}

/**
* 解析处理(生成实体类主体代码)
*
* @throws Exception
*/
private String parse(String[] colNames, String[] colTypes, int[] colSizes,
String path, String tableName) throws Exception {
StringBuffer sb = new StringBuffer();

sb.append("import lombok.Data;\r\n");
if (f_util) {
sb.append("\r\n");
sb.append("import java.util.Date;\r\n");
}
if (f_sql) {
sb.append("\r\n");
sb.append("import java.sql.*;\r\n\r\n\r\n");
}
sb.append("@Data\r\n");
sb.append("public class " + initcap(tableName)
+ " extends AbstractEntity" + " {\r\n");
processAllAttrs(sb);
// processAllMethod(sb);
sb.append("}\r\n");

// 将string流写入文件
FileOperation.writeTxtFile(sb.toString(), new File(path
+ initcap(tableName) + ".java"));
System.out.println(sb.toString());
return sb.toString();

}

/**
* 生成所有的方法
*
* @param sb
*/
@SuppressWarnings("unused")
private void processAllMethod(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
sb.append("\tpublic void set" + initcap(colnames[i]) + "("
+ sqlType2JavaType(colTypes[i]) + " " + colnames[i]
+ "){\r\n");
sb.append("\t\tthis." + colnames[i] + "=" + colnames[i] + ";\r\n");
sb.append("\t}\r\n");

sb.append("\tpublic " + sqlType2JavaType(colTypes[i]) + " get"
+ initcap(colnames[i]) + "(){\r\n");
sb.append("\t\treturn " + colnames[i] + ";\r\n");
sb.append("\t}\r\n");
}
}

/**
* 解析输出属性
*
* @return
*/
private void processAllAttrs(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
sb.append("\r\n");
sb.append("\t@Column(name = \"" + colnames[i] + "\")\r\n");
sb.append("\tprivate " + sqlType2JavaType(colTypes[i]) + " "
+ colnames[i] + ";\r\n");
}
}

/**
* 把输入字符串的首字母改成大写
*
* @param str
* @return
*/
private String initcap(String str) {
char[] ch = str.toCharArray();
if (ch[0] >= 'a' && ch[0] <= 'z') {
ch[0] = (char) (ch[0] - 32);
}
return new String(ch);
}

/**
* 将所有数据库中的字段类型转换为java中类型
*
* @param sqlType
* @return
*/
private String sqlType2JavaType(String sqlType) {
if (sqlType.equalsIgnoreCase("bit")) {
return "bool";
} else if (sqlType.equalsIgnoreCase("tinyint")) {
return "byte";
} else if (sqlType.equalsIgnoreCase("smallint")) {
return "short";
} else if (sqlType.equalsIgnoreCase("int")) {
return "int";
} else if (sqlType.equalsIgnoreCase("bigint")) {
return "long";
} else if (sqlType.equalsIgnoreCase("float")) {
return "float";
} else if (sqlType.equalsIgnoreCase("decimal")
|| sqlType.equalsIgnoreCase("numeric")
|| sqlType.equalsIgnoreCase("real")) {
return "double";
} else if (sqlType.equalsIgnoreCase("money")
|| sqlType.equalsIgnoreCase("smallmoney")) {
return "double";
} else if (sqlType.equalsIgnoreCase("varchar")
|| sqlType.equalsIgnoreCase("char")
|| sqlType.equalsIgnoreCase("nvarchar")
|| sqlType.equalsIgnoreCase("nchar")) {
return "String";
} else if (sqlType.equalsIgnoreCase("datetime")) {
return "Date";
}

else if (sqlType.equalsIgnoreCase("image")) {
return "Blob";
} else if (sqlType.equalsIgnoreCase("text")) {
return "Clob";
}
return null;
}

public static void main(String[] args) throws Exception {
CreateBean createBean = new CreateBean();
String javaFileSavePath = "D:\\wer\\"; //
String DBname = "enrichmind";
createBean.createBeanMethod(DBname, javaFileSavePath);

}
}