我的tomcat7实现是接受字符串作为ISO-8859-1;不管HTTP请求的内容类型是什么。当我试图正确解释'é'这样的字符时，下面的解决方案对我有效。

byte[] b1 = szP1.getBytes("ISO-8859-1");
System.out.println(b1.toString());

String szUT8 = new String(b1, "UTF-8");
System.out.println(szUT8);

当试图将字符串解释为US-ASCII时，字节信息没有正确解释。

b1 = szP1.getBytes("US-ASCII");
System.out.println(b1.toString());

将字符串转换为字节[]:

String s = "some text here";
byte[] b = s.getBytes(StandardCharsets.UTF_8);

将字节[]转换为字符串:

byte[] b = {(byte) 99, (byte)97, (byte)116};
String s = new String(b, StandardCharsets.US_ASCII);

当然，您应该使用正确的编码名称。我的示例使用了US-ASCII和UTF-8这两种常用的编码。

//query is your json   

 DefaultHttpClient httpClient = new DefaultHttpClient();
 HttpPost postRequest = new HttpPost("http://my.site/test/v1/product/search?qy=");

 StringEntity input = new StringEntity(query, "UTF-8");
 input.setContentType("application/json");
 postRequest.setEntity(input);   
 HttpResponse response=response = httpClient.execute(postRequest);

为了解码一系列字节到一个正常的字符串消息，我最终得到了它与UTF-8编码工作与以下代码:

/* Convert a list of UTF-8 numbers to a normal String
 * Usefull for decoding a jms message that is delivered as a sequence of bytes instead of plain text
 */
public String convertUtf8NumbersToString(String[] numbers){
    int length = numbers.length;
    byte[] data = new byte[length];

    for(int i = 0; i< length; i++){
        data[i] = Byte.parseByte(numbers[i]);
    }
    return new String(data, Charset.forName("UTF-8"));
}

String original = "hello world";
byte[] utf8Bytes = original.getBytes("UTF-8");

这里有一个解决方案，避免执行Charset查找每次转换:

import java.nio.charset.Charset;

private final Charset UTF8_CHARSET = Charset.forName("UTF-8");

String decodeUTF8(byte[] bytes) {
    return new String(bytes, UTF8_CHARSET);
}

byte[] encodeUTF8(String string) {
    return string.getBytes(UTF8_CHARSET);
}