重构代码

webmagic-extension/src/main/java/us/codecraft/webmagic/utils/MySQLTool.java

 package us.codecraft.webmagic.utils;
 
 import com.alibaba.druid.pool.DruidDataSource;
+import com.google.common.base.Preconditions;
 import org.apache.commons.dbutils.QueryRunner;
+import org.apache.commons.lang3.StringUtils;
 
 import java.sql.SQLException;
 
-
 public class MySQLTool {
 
     private DruidDataSource dataSource;
@@ -14,18 +15,50 @@ public class MySQLTool {
 
     private String insertSql;
 
-    public MySQLTool setInsertSql(String insertSql){
-        this.insertSql = insertSql;
-        return this;
-    }
-
-    public MySQLTool(String url, String userName, String password){
+    private MySQLTool(Builder builder){
         dataSource = new DruidDataSource();
         dataSource.setDriverClassName("com.mysql.jdbc.Driver");
-        dataSource.setUrl(url);
-        dataSource.setUsername(userName);
-        dataSource.setPassword(password);
+        dataSource.setUrl(builder.url);
+        dataSource.setUsername(builder.userName);
+        dataSource.setPassword(builder.password);
         queryRunner = new QueryRunner(dataSource);
+        this.insertSql = builder.insertSql;
+    }
+
+    public static class Builder{
+        private String url;
+        private String userName;
+        private String password;
+        private String insertSql;
+
+        public Builder setUrl(String url) {
+            this.url = url;
+            return this;
+        }
+
+        public Builder setUserName(String userName) {
+            this.userName = userName;
+            return this;
+        }
+
+        public Builder setPassword(String password) {
+            this.password = password;
+            return this;
+        }
+
+        public Builder setInsertSql(String insertSql) {
+            this.insertSql = insertSql;
+            return this;
+        }
+
+        public MySQLTool build(){
+            Preconditions.checkArgument(StringUtils.isNotEmpty(this.url),"数据库连接信息不能为空");
+            Preconditions.checkArgument(StringUtils.isNotEmpty(this.userName),"数据库用户名不能为空");
+            Preconditions.checkArgument(StringUtils.isNotEmpty(this.password),"数据库密码不能为空");
+            Preconditions.checkArgument(StringUtils.isNotEmpty(this.insertSql),"数据库插入语句不能为空");
+
+            return new MySQLTool(this);
+        }
     }
 
     public void insert(Object...params) throws SQLException {