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import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
/**
* 数据库表转换成javaBean对象小工具(已用了很长时间),
* 1 bean属性按原始数据库字段经过去掉下划线,并大写处理首字母等等.
* 2 生成的bean带了数据库的字段说明.
* 3 各位自己可以修改此工具用到项目中去.
*/
public class MyEntityUtils {
private String tablename = "";
private String[] colnames;
private String[] colTypes;
private int[] colSizes; // 列名大小
private int[] colScale; // 列名小数精度
private boolean importUtil = false;
private boolean importSql = false;
private boolean importMath = false;
/**
* @param args
* 各位按自己的
*/
public void tableToEntity(String tName) {
tablename = tName;
//数据连Connection获取,自己想办法就行.
Connection conn = null;
String strsql = "SELECT * FROM " + tablename;//+" WHERE ROWNUM=1" 读一行记录;
try {
System.out.println(strsql);
PreparedStatement pstmt = conn.prepareStatement(strsql);
pstmt.executeQuery();
ResultSetMetaData rsmd = pstmt.getMetaData();
int size = rsmd.getColumnCount(); // 共有多少列
colnames = new String[size];
colTypes = new String[size];
colSizes = new int[size];
colScale = new int[size];
for (int i = 0; i < rsmd.getColumnCount(); i++) {
rsmd.getCatalogName(i + 1);
colnames[i] = rsmd.getColumnName(i + 1).toLowerCase();
colTypes[i] = rsmd.getColumnTypeName(i + 1).toLowerCase();
colScale[i] = rsmd.getScale(i + 1);
System.out.println(rsmd.getCatalogName(i+1));
if ("datetime".equals(colTypes[i])) {
importUtil = true;
}
if ("image".equals(colTypes[i]) || "text".equals(colTypes[i])) {
importSql = true;
}
if(colScale[i]>0){
importMath = true;
}
colSizes[i] = rsmd.getPrecision(i + 1);
}
String content = parse(colnames, colTypes, colSizes);
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 {
if(conn!=null) conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
/**
* 解析处理(生成实体类主体代码)
*/
private String parse(String[] colNames, String[] colTypes, int[] colSizes) {
StringBuffer sb = new StringBuffer();
sb.append("\r\nimport java.io.Serializable;\r\n");
if (importUtil) {
sb.append("import java.util.Date;\r\n");
}
if (importSql) {
sb.append("import java.sql.*;\r\n\r\n");
}
if(importMath){
sb.append("import java.math.*;\r\n\r\n");
}
//表注释
processColnames(sb);
sb.append("public class " + initcap(tablename) + " implements Serializable {\r\n");
processAllAttrs(sb);
processAllMethod(sb);
sb.append("}\r\n");
System.out.println(sb.toString());
return sb.toString();
}
/**
* 处理列名,把空格下划线‘_‘去掉,同时把下划线后的首字母大写
* 要是整个列在3个字符及以内,则去掉‘_‘后,不把"_"后首字母大写.
* 同时把数据库列名,列类型写到注释中以便查看,
* @param sb
*/
private void processColnames(StringBuffer sb) {
sb.append("\r\n/** " + tablename + "\r\n");
String colsiz="";
String colsca="";
for (int i = 0; i < colnames.length; i++) {
colsiz = colSizes[i]<=0? "" : (colScale[i]<=0? "("+colSizes[i]+")" : "("+colSizes[i]+","+colScale[i]+")");
sb.append("\t" + colnames[i].toUpperCase() +" "+colTypes[i].toUpperCase()+ colsiz+"\r\n");
char[] ch = colnames[i].toCharArray();
char c =‘a‘;
if(ch.length>3){
for(int j=0;j <ch.length; j++){
c = ch[j];
if(c == ‘_‘){
if (ch[j+1]>= ‘a‘ && ch[j+1] <= ‘z‘) {
ch[j+1]=(char) (ch[j+1]-32);
}
}
}
}
String str = new String(ch);
colnames[i] = str.replaceAll("_", "");
}
sb.append("*/\r\n");
}
/**
* 生成所有的方法
*
* @param sb
*/
private void processAllMethod(StringBuffer sb) {
for (int i = 0; i < colnames.length; i++) {
sb.append("\tpublic void set" + initcap(colnames[i]) + "("
+ oracleSqlType2JavaType(colTypes[i],colScale[i],colSizes[i]) + " " + colnames[i]
+ "){\r\n");
sb.append("\t\tthis." + colnames[i] + "=" + colnames[i] + ";\r\n");
sb.append("\t}\r\n");
sb.append("\tpublic " + oracleSqlType2JavaType(colTypes[i],colScale[i],colSizes[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) {
sb.append("\tprivate static final long serialVersionUID = 1L;\r\n");
for (int i = 0; i < colnames.length; i++) {
sb.append("\tprivate " + oracleSqlType2JavaType(colTypes[i],colScale[i],colSizes[i]) + " "
+ colnames[i] + ";\r\n");
}
sb.append("\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);
}
/**
* Oracle
* @param sqlType
* @param scale
* @return
*/
private String oracleSqlType2JavaType(String sqlType, int scale,int size) {
if (sqlType.equals("integer")) {
return "Integer";
} else if (sqlType.equals("long")) {
return "Long";
} else if (sqlType.equals("float")
|| sqlType.equals("float precision")
|| sqlType.equals("double")
|| sqlType.equals("double precision")
) {
return "BigDecimal";
}else if (sqlType.equals("number")
||sqlType.equals("decimal")
|| sqlType.equals("numeric")
|| sqlType.equals("real")) {
return scale==0? (size<10? "Integer" : "Long") : "BigDecimal";
}else if (sqlType.equals("varchar")
|| sqlType.equals("varchar2")
|| sqlType.equals("char")
|| sqlType.equals("nvarchar")
|| sqlType.equals("nchar")) {
return "String";
} else if (sqlType.equals("datetime")
|| sqlType.equals("date")
|| sqlType.equals("timestamp")) {
return "Date";
}
return null;
}
/**
* @param args
*/
public static void main(String[] args) {
MyEntityUtils t = new MyEntityUtils();
t.tableToEntity("TABLE");
}
}
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原文地址：http://www.cnblogs.com/zzw1787044/p/4206802.html
