依赖:
<!--lang3工具包,SpringBoot控制依赖版本-->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
</dependency>
org.apache.commons.lang3.StringUtils类提供了String的常用操作,最为常用的判空有如下两种isEmpty(String str)和isBlank(String str)。
用法区别:
1.StringUtils.isEmpty(String str) 判断某字符串是否为空，为空的标准是 str==null 或 str.length()==0
System.out.println(StringUtils.isEmpty(null)); //true
System.out.println(StringUtils.isEmpty("")); //true
System.out.println(StringUtils.isEmpty(" ")); //false
System.out.println(StringUtils.isEmpty("dd")); //false
//StringUtils.isNotEmpty(String str) 等价于 !isEmpty(String str)
2.StringUtils.isBlank(String str) 判断某字符串是否为空或长度为0或由空白符(whitespace) 构成
System.out.println(StringUtils.isBlank(null)); //true
System.out.println(StringUtils.isBlank("")); //true
System.out.println(StringUtils.isBlank(" ")); //true
System.out.println(StringUtils.isBlank("dd")); //false
//StringUtils.isBlank(String str) 等价于 !isBlank(String str)
自己造轮子?
自定义判断方法,实现同样的判断逻辑
/**
* 判断对象是否为null,不允许空白串
*
* @param object 目标对象类型
* @return
*/
public static boolean isNull(Object object){
if (null == object) {
return true;
}
if ((object instanceof String)){
return "".equals(((String)object).trim());
}
return false;
}
/**
* 判断对象是否不为null
*
* @param object
* @return
*/
public static boolean isNotNull(Object object){
return !isNull(object);
}
System.out.println(StringHandler.isNull(null)); //true
System.out.println(StringHandler.isNull("")); //true
System.out.println(StringHandler.isNull(" ")); //true
System.out.println(StringHandler.isNull("dd")); //false
常用的String操作
1.字符串编码转换
/**
* change UTF8 To GB2312
* @param target
* @return
*/
public static final String UTF82GB2312(String target) {
try {
return new String(target.getBytes("UTF-8"), "gb2312");
} catch (Exception localException) {
System.err.println("UTF8 TO GB2312 change error!");
}
return null;
}
/**
* change UTF8 To GBK
* @param target
* @return
*/
public static final String UTF82GBK(String target) {
try {
return new String(target.getBytes("UTF-8"), "GBK");
} catch (Exception localException) {
System.err.println("UTF8 TO GBK change error!");
}
return null;
}
/**
* change UTF8 To ISO8859-1
* @param target
* @return
*/
public static final String UTF82ISO(String target) {
try {
return new String(target.getBytes("UTF-8"), "ISO8859-1");
} catch (Exception localException) {
System.err.println("UTF8 TO ISO8859-1 change error!");
}
return null;
}
/**
* change Windows-1252 To UTF-8
* @param target
* @return
*/
public static final String Windows1252UTF8(String target) {
try {
return new String(target.getBytes("Windows-1252"), "UTF-8");
} catch (Exception localException) {
System.err.println("Windows1252 To UTF8 chage error");
}
return null;
}
2.文本追加高亮
/**
* 给串增加颜色标签
* @param color
* @param target
* @return
*/
public static String withColor(String color, String target) {
return withColor(color, target,true);
}
/**
* 给串增加颜色标签
* @param color
* @param target
* @param paramBoolean
* @return
*/
public static String withColor(String color, String target, boolean paramBoolean) {
if (paramBoolean)
return "<font color='".concat(color).concat("'>").concat(target).concat("</font>");
return target;
}
System.out.println(StringHandler.withColor("red","文本串", true));
<font color='red'>文本串</font>
