StringUtils工具类的使用

来源：中国IT实验室作者：佚名出处：巧巧读书 2008-05-29 进入讨论组

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    一、数组转成字符串：
    1、将数组中的字符转换为一个字符串
    将数组中的字符转换为一个字符串

    @param strToConv 要转换的字符串 ,默认以逗号分隔
    @return 返回一个字符串
    String[3] s={"a","b","c"}
    StringUtil.convString（s)="a,b,c"
    2、 static public String converString(String strToConv)
    @param strToConv 要转换的字符串 ,
    @param conv 分隔符,默认以逗号分隔
    @return 同样返回一个字符串

    String[3] s={"a","b","c"}
    StringUtil.convString（s,"@")="a@b@c"
    static public String converString(String strToConv, String conv)

二、空值检测：
3、

Checks if a String is empty ("") or null.

判断一个字符串是否为空，空格作非空处理。 StringUtils.isEmpty(null) = true StringUtils.isEmpty("") = true StringUtils.isEmpty(" ") = false StringUtils.isEmpty("bob") = false StringUtils.isEmpty(" bob ") = false

NOTE: This method changed in Lang version 2.0.

It no longer trims the String.
That functionality is available in isBlank().

    @param str the String to check, may be null
    @return true if the String is empty or null
    public static boolean isEmpty(String str)

    三、非空处理：
    4、
    Checks if a String is not empty ("") and not null.

判断一个字符串是否非空，空格作非空处理. StringUtils.isNotEmpty(null) = false StringUtils.isNotEmpty("") = false StringUtils.isNotEmpty(" ") = true StringUtils.isNotEmpty("bob") = true StringUtils.isNotEmpty(" bob ") = true

    @param str the String to check, may be null
    @return true if the String is not empty and not null
    public static boolean isNotEmpty(String str)

5、

Checks if a String is not empty (""), not null and not whitespace only.

判断一个字符串是否非空，空格作空处理. StringUtils.isNotBlank(null) = false StringUtils.isNotBlank("") = false StringUtils.isNotBlank(" ") = false StringUtils.isNotBlank("bob") = true StringUtils.isNotBlank(" bob ") = true

    @param str the String to check, may be null
    @return true if the String is
    not empty and not null and not whitespace
    @since 2.0
    public static boolean isNotBlank(String str)

    四、空格处理
    6、
    Removes control characters (char <= 32) from both

ends of this String, handling null by returning
null.

The String is trimmed using {@link String#trim()}.

Trim removes start and end characters <= 32.
To strip whitespace use {@link //strip(String)}.

To trim your choice of characters, use the

{@link //strip(String, String)} methods.

格式化一个字符串中的空格，有非空判断处理； StringUtils.trim(null) = null StringUtils.trim("") = "" StringUtils.trim(" ") = "" StringUtils.trim("abc") = "abc" StringUtils.trim(" abc ") = "abc"

    @param str the String to be trimmed, may be null
    @return the trimmed string, null if null String input
    public static String trim(String str)

7、

Removes control characters (char <= 32) from both

ends of this String returning null if the String is
empty ("") after the trim or if it is null.

The String is trimmed using {@link String#trim()}.

Trim removes start and end characters <= 32.
To strip whitespace use {@link /stripToNull(String)}.

格式化一个字符串中的空格，有非空判断处理，如果为空返回null； StringUtils.trimToNull(null) = null StringUtils.trimToNull("") = null StringUtils.trimToNull(" ") = null StringUtils.trimToNull("abc") = "abc" StringUtils.trimToNull(" abc ") = "abc"

    @param str the String to be trimmed, may be null
    @return the trimmed String,
    null if only chars <= 32, empty or null String input
    @since 2.0
    public static String trimToNull(String str)

8、

Removes control characters (char <= 32) from both

ends of this String returning an empty String ("") if the String
is empty ("") after the trim or if it is null.

The String is trimmed using {@link String#trim()}.

Trim removes start and end characters <= 32.
To strip whitespace use {@link /stripToEmpty(String)}.

格式化一个字符串中的空格，有非空判断处理，如果为空返回""； StringUtils.trimToEmpty(null) = "" StringUtils.trimToEmpty("") = "" StringUtils.trimToEmpty(" ") = "" StringUtils.trimToEmpty("abc") = "abc" StringUtils.trimToEmpty(" abc ") = "abc"

    @param str the String to be trimmed, may be null
    @return the trimmed String, or an empty String if null input
    @since 2.0
    public static String trimToEmpty(String str)

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